Merge pull request #4 from xdrm-io/test/coverage

improve test coverage to 80% for every package

.drone.yml

@@ -1,11 +0,0 @@
----
-kind: pipeline
-type: docker
-name: default
-
-steps:
-- name: test
-  image: golang:1.13
-  commands:
-  - go get ./...
-  - go test -v -race -cover -coverprofile ./coverage.out ./...

.github/workflows/go.yml

@@ -0,0 +1,27 @@
+name: Go
+
+on:
+  push:
+    branches:
+      - '**'
+  pull_request:
+    branches:
+      - '**'
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: 1.16
+
+    - name: Build
+      run: go build -v ./...
+
+    - name: Test
+      run: go test -race -v ./... -cover

README.md

@@ -1,215 +1,339 @@
-# | aicra |
+<p align="center">
+  <a href="https://github.com/xdrm-io/aicra">
+    <img src="https://github.com/xdrm-io/aicra/raw/0.4.0/readme.assets/logo.png" alt="aicra logo" width="200" height="200">
+  </a>
+</p>
+
+<h3 align="center">aicra</h3>
+
+<p align="center">
+  Fast, intuitive, and powerful configuration-driven engine for faster and easier <em>REST</em> development.
+</p>
 
-[![Go version](https://img.shields.io/badge/go_version-1.10.3-blue.svg)](https://golang.org/doc/go1.10)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
-[![Go Report Card](https://goreportcard.com/badge/git.xdrm.io/go/aicra)](https://goreportcard.com/report/git.xdrm.io/go/aicra)
-[![Go doc](https://godoc.org/git.xdrm.io/go/aicra?status.svg)](https://godoc.org/git.xdrm.io/go/aicra)
-[![Build Status](https://drone.xdrm.io/api/badges/go/aicra/status.svg)](https://drone.xdrm.io/go/aicra)
+[![Go version](https://img.shields.io/badge/go_version-1.16-blue.svg)](https://golang.org/doc/go1.16)
+[![Go doc](https://pkg.go.dev/badge/github.com/xdrm-io/aicra)](https://pkg.go.dev/github.com/xdrm-io/aicra)
+[![Go Report Card](https://goreportcard.com/badge/github.com/xdrm-io/aicra)](https://goreportcard.com/report/github.com/xdrm-io/aicra)
+[![Build status](https://github.com/xdrm-io/aicra/actions/workflows/go.yml/badge.svg)](https://github.com/xdrm-io/aicra/actions/workflows/go.yml)
 
+## Presentation
 
-**Aicra** is a *configuration-driven* **web framework** written in Go that allows you to create a fully featured REST API.
+`aicra` is a lightweight and idiomatic configuration-driven engine for building REST services. It's especially good at helping you write large APIs that remain maintainable as your project grows.
 
-The whole management is done for you from a configuration file describing your API, you're left with implementing :
-- handlers
-- optionnally middle-wares (_e.g. authentication, csrf_)
-- and optionnally your custom type checkers to check input parameters
+The focus of the project is to allow you to build a fully-featured REST API in an elegant, comfortable and inexpensive way. This is achieved by using a single configuration file to drive the server. This one file describes your entire API: methods, uris, input data, expected output, permissions, etc.
 
+Repetitive tasks are automatically processed by `aicra` based on your configuration, you're left with implementing your handlers (_usually business logic_).
 
-The aicra server fulfills the `net/http` [Server interface](https://golang.org/pkg/net/http/#Server).
-
-
-
-> A example project is available [here](https://git.xdrm.io/go/tiny-url-ex)
-
-
-### Table of contents
+## Table of contents
 
 <!-- toc -->
 
-- [I/ Installation](#i-installation)
-- [II/ Development](#ii-development)
-	* [1) Main executable](#1-main-executable)
-	* [2) API Configuration](#2-api-configuration)
-			- [Definition](#definition)
-		+ [Input Arguments](#input-arguments)
-			- [1. Input types](#1-input-types)
-			- [2. Global Format](#2-global-format)
-- [III/ Change Log](#iii-change-log)
+- [Installation](#installation)
+- [What's automated](#whats-automated)
+- [Getting started](#getting-started)
+- [Configuration file](#configuration-file)
+  * [Services](#services)
+  * [Input and output parameters](#input-and-output-parameters)
+  * [Example](#example)
+- [Writing your code](#writing-your-code)
+- [Changelog](#changelog)
 
 <!-- tocstop -->
 
-### I/ Installation
-
-You need a recent machine with `go` [installed](https://golang.org/doc/install). This package has not been tested under the version **1.10**.
+## Installation
 
+To install the aicra package, you need to install Go and set your Go workspace first.
+> not tested under Go 1.14
 
+1. you can use the below Go command to install aicra.
 ```bash
-go get -u git.xdrm.io/go/aicra/cmd/aicra
+$ go get -u github.com/xdrm-io/aicra
+```
+2. Import it in your code:
+```go
+import "github.com/xdrm-io/aicra"
 ```
 
-The library should now be available as `git.xdrm.io/go/aicra` in your imports.
+## What's automated
 
+As the configuration file is here to make your life easier, let's take a quick look at what you do not have to do ; or in other words, what does `aicra` automates.
 
-### II/ Development
+Http requests are only accepted when they have the permissions you have defined. If unauthorized, the request is rejected with an error response.
 
+Request data is automatically extracted and validated before it reaches your code. If a request has missing or invalid data an automatic error response is sent.
 
-#### 1) Main executable
+When launching the server, it ensures everything is ok and won't start until fixed. You will get errors for:
+- handler signature does not match the configuration
+- a configuration service has no handler
+- a handler does not match any service
 
-Your main executable will declare and run the aicra server, it might look quite like the code below.
+The same applies if your configuration is invalid:
+- unknown HTTP method
+- invalid uri
+- uri collision between 2 services
+- missing fields
+- unknown data type
+- input name collision
+
+## Getting started
+
+Here is the minimal code to launch your aicra server assuming your configuration file is `api.json`.
 
 ```go
 package main
 
 import (
-		"log"
-		"net/http"
+    "log"
+    "net/http"
+    "os"
 
-		"git.xdrm.io/go/aicra"
-		"git.xdrm.io/go/aicra/datatype"
-		"git.xdrm.io/go/aicra/datatype/builtin"
+    "github.com/xdrm-io/aicra"
+    "github.com/xdrm-io/aicra/api"
+    "github.com/xdrm-io/aicra/validator/builtin"
 )
 
 func main() {
+    builder := &aicra.Builder{}
 
-	// 1. select your datatypes (builtin, custom)
-	var dtypes []datatype.T
-	dtypes = append(dtypes, builtin.AnyDataType{})
-	dtypes = append(dtypes, builtin.BoolDataType{})
-	dtypes = append(dtypes, builtin.UintDataType{})
-	dtypes = append(dtypes, builtin.StringDataType{})
+    // add custom type validators
+    builder.Validate(validator.BoolDataType{})
+    builder.Validate(validator.UintDataType{})
+    builder.Validate(validator.StringDataType{})
 
-	// 2. create the server from the configuration file
-	server, err := aicra.New("path/to/your/api/definition.json", dtypes...)
-	if err != nil {
-		log.Fatalf("cannot built aicra server: %s\n", err)
-	}
+    // load your configuration
+    config, err := os.Open("api.json")
+    if err != nil {
+        log.Fatalf("cannot open config: %s", err)
+    }
+    err = builder.Setup(config)
+    config.Close() // free config file
+    if err != nil {
+        log.Fatalf("invalid config: %s", err)
+    }
 
-	// 3. bind your implementations
-	server.HandleFunc(http.MethodGet, "/path", func(req api.Request, res *api.Response){
-		// ... process stuff ...
-		res.SetError(api.ErrorSuccess());
-	})
+    // add http middlewares (logger)
+    builder.With(func(next http.Handler) http.Handler{ /* ... */ })
 
-	// 4. extract to http server
-	httpServer, err := server.ToHTTPServer()
-	if err != nil {
-		log.Fatalf("cannot get to http server: %s", err)
-	}
+    // add contextual middlewares (authentication)
+    builder.WithContext(func(next http.Handler) http.Handler{ /* ... */ })
 
-	// 4. launch server
-	log.Fatal( http.ListenAndServe("localhost:8080", server) )
+    // bind handlers
+    err = builder.Bind(http.MethodGet, "/user/{id}", getUserById)
+    if err != nil {
+        log.Fatalf("cannog bind GET /user/{id}: %s", err)
+    }
+
+    // build your services
+    handler, err := builder.Build()
+    if err != nil {
+        log.Fatalf("cannot build handler: %s", err)
+    }
+    http.ListenAndServe("localhost:8080", handler)
 }
 ```
 
+If you want to use HTTPS, you can configure your own `http.Server`.
+```go
+func main() {
+    server := &http.Server{
+        Addr:      "localhost:8080",
+		TLSConfig: tls.Config{},
+        // ...
+		Handler:   AICRAHandler,
+	}
+    server.ListenAndServe()
+}
+```
 
+## Configuration file
 
-#### 2) API Configuration
+First of all, the configuration uses `json`.
 
-The whole project behavior is described inside a json file (_e.g. usually api.json_). For a better understanding of the format, take a look at this working [template](https://git.xdrm.io/go/tiny-url-ex/src/master/api.json). This file defines :
-
-- routes and their methods
-- every input for each method (called *argument*)
-- every output for each method
-- scope permissions (list of permissions needed by clients)
-- input policy :
-	- type of argument (_i.e. for data types_)
-	- required/optional
-	- variable renaming
-
-
-
-###### Definition
-
-The root of the json file must be an array containing your requests definitions.
-
-For each, you will have to create fields described in the table above.
-
-| field path | description                                                  | example                                                      |
-| ---------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
-| `info`     | A short human-readable description of what the method does   | `create a new user`                                          |
-| `scope`    | A 2-dimensional array of permissions. The first dimension can be translated to a **or** operator, the second dimension as a **and**. It allows you to combine permissions in complex ways. | `[["A", "B"], ["C", "D"]]` can be translated to : this method needs users to have permissions (A **and** B) **or** (C **and** D) |
-| `in`       | The list of arguments that the clients will have to provide. See [here](#input-arguments) for details. |                                                              |
-| `out`      | The list of output data that will be returned by your controllers. It has the same syntax as the `in` field but is only use for readability purpose and documentation. |                                                              |
-
-
-##### Input Arguments
-
-###### 1. Input types
-
-Input arguments defines what data from the HTTP request the method needs. Aicra is able to extract 3 types of data :
-
-- **URI** - Curly Braces enclosed strings inside the request path. For instance, if your controller is bound to the `/user/{id}` URI, you can set the input argument `{id}` matching this uri part.
-- **Query** - data formatted at the end of the URL following the standard [HTTP Query](https://tools.ietf.org/html/rfc3986#section-3.4) syntax.
-- **URL encoded** - data send inside the body of the request but following the [HTTP Query](https://tools.ietf.org/html/rfc3986#section-3.4) syntax.
-- **Multipart** - data send inside the body of the request with a dedicated [format](https://tools.ietf.org/html/rfc2388#section-3). This format is not very lightweight but allows you to receive data as well as files.
-- **JSON** - data send inside the body as a json object ; each key being a variable name, each value its content. Note that the HTTP header '**Content-Type**' must be set to `application/json` for the API to use it.
-
-
-
-###### 2. Global Format
-
-The `in` field in each method contains as list of arguments where the key is the argument name, and the value defines how to manage the variable.
-
-> Variable names from **URI** or **Query** must be named accordingly :
+> Quick note if you thought: "I hate JSON, I would have preferred yaml, or even xml !"
 >
-> - the **URI** variable `{id}` from your request route must be named `{id}`.
-> - the variable `somevar` in the **Query** has to be names `GET@somevar`.
+> I've had a hard time deciding and testing different formats including yaml and xml.
+> But as it describes our entire api and is crucial for our server to keep working over updates; xml would have been too verbose with growth and yaml on the other side would have been too difficult to read. Json sits in the right spot for this.
 
-**Example**
+Let's take a quick look at the configuration format !
 
-In this example we want 3 arguments :
+> if you don't like boring explanations and prefer a working example, see [here](https://git.xdrm.io/go/articles-api/src/master/api.json)
 
-- the 1^st^ one is send at the end of the URI and is a number compliant with the `int` type checker. It is renamed `article_id`, this new name will be sent to the handler.
-- the 2^nd^ one is send in the query (_e.g. [http://host/uri?get-var=value](http://host/uri?get-var=value)_). It must be a valid `string` or not given at all (the `?` at the beginning of the type tells that the argument is **optional**) ; it will be named `title`.
-- the 3^rd^ can be send with a **JSON** body, in **multipart** or **URL encoded** it makes no difference and only give clients a choice over the technology to use. If not renamed, the variable will be given to the handler with the name `content`.
+### Services
 
+To begin with, the configuration file defines a list of services. Each one is defined by:
+- `method` an HTTP method
+- `path` an uri pattern (can contain variables)
+- `info` a short description of what it does
+- `scope` a list of the required permissions
+- `in` a list of input arguments
+- `out` a list of output arguments
 ```json
 [
-	{
-		"method": "PUT",
-		"path": "/article/{id}",
-		"scope": [["author"]],
-		"info": "updates an article",
-		"in": {
-			"{id}":      { "info": "article id",          "type": "int",     "name": "article_id" },
-			"GET@title": { "info": "new article title",   "type": "?string", "name": "title"      },
-			"content":   { "info": "new article content", "type": "string"                        }
-		},
-		"out": {
-			"id":      { "info": "updated article id",      "type": "uint"   },
-			"title":   { "info": "updated article title",   "type": "string" },
-			"content": { "info": "updated article content", "type": "string" }
-		}
-	}
+    {
+        "method": "GET",
+        "path": "/article",
+        "scope": [["author", "reader"], ["admin"]],
+        "info": "returns all available articles",
+        "in": {},
+        "out": {}
+    }
 ]
 ```
 
+The `scope` is a 2-dimensional list of permissions. The first list means **or**, the second means **and**, it allows for complex permission combinations. The example above can be translated to: this method requires users to have permissions (author **and** reader) **or** (admin)
+
+### Input and output parameters
+
+Input and output parameters share the same format, featuring:
+- `info` a short description of what it is
+- `type` its data type (_c.f. validation_)
+- `?` whether it is mandatory or optional
+- `name` a custom name for easy access in code
+```json
+[
+    {
+        "method": "PUT",
+        "path": "/article/{id}",
+        "scope": [["author"]],
+        "info": "updates an article",
+        "in": {
+            "{id}":      { "info": "...", "type": "int",     "name": "id"    },
+            "GET@title": { "info": "...", "type": "?string", "name": "title" },
+            "content":   { "info": "...", "type": "string"                   }
+        },
+        "out": {
+            "title":   { "info": "updated article title",   "type": "string" },
+            "content": { "info": "updated article content", "type": "string" }
+        }
+    }
+]
+```
+
+If a parameter is optional you just have to prefix its type with a question mark, by default all parameters are mandatory.
+
+The format of the key of input arguments defines where it comes from:
+1. `{param}` is an URI parameter that is extracted from the `"path"`
+2. `GET@param` is an URL parameter that is extracted from the [HTTP Query](https://tools.ietf.org/html/rfc3986#section-3.4) syntax.
+3. `param` is a body parameter that can be extracted from 3 formats independently:
+    - _url encoded_: data send in the body following the [HTTP Query](https://tools.ietf.org/html/rfc3986#section-3.4) syntax.
+    - _multipart_: data send in the body with a dedicated [format](https://tools.ietf.org/html/rfc2388#section-3). This format can be quite heavy but allows to transmit data as well as files.
+    - _JSON_: data sent in the body as a json object ; The _Content-Type_ header must be `application/json` for it to work.
+
+### Example
+```json
+[
+    {
+        "method": "PUT",
+        "path": "/article/{id}",
+        "scope": [["author"]],
+        "info": "updates an article",
+        "in": {
+            "{id}":      { "info": "...", "type": "int",     "name": "id"    },
+            "GET@title": { "info": "...", "type": "?string", "name": "title" },
+            "content":   { "info": "...", "type": "string"                   }
+        },
+        "out": {
+            "id":      { "info": "updated article id",      "type": "uint"   },
+            "title":   { "info": "updated article title",   "type": "string" },
+            "content": { "info": "updated article content", "type": "string" }
+        }
+    }
+]
+```
+
+1. `{id}` is extracted from the end of the URI and is a number compliant with the `int` type checker. It is renamed `ID`, this new name will be sent to the handler.
+2. `GET@title` is extracted from the query (_e.g. [http://host/uri?get-var=value](http://host/uri?get-var=value)_). It must be a valid `string` or not given at all (the `?` at the beginning of the type tells that the argument is **optional**) ; it will be named `title`.
+3. `content` can be extracted from json, multipart or url-encoded data; it makes no difference and only give clients a choice over the technology to use. If not renamed, the variable will be given to the handler with its original name `content`.
 
 
-### III/ Change Log
+
+## Writing your code
+
+Besides your main package where you launch your server, you will need to create handlers matching services from the configuration.
+
+The code below implements a simple handler.
+```go
+// "in": {
+//  "Input1": { "info": "...", "type": "int"     },
+//  "Input2": { "info": "...", "type": "?string" }
+// },
+type req struct{
+    Input1 int
+    Input2 *string // optional are pointers
+}
+// "out": {
+//  "Output1": { "info": "...", "type": "string" },
+//  "Output2": { "info": "...", "type": "bool"   }
+// }
+type res struct{
+    Output1 string
+    Output2 bool
+}
+
+func myHandler(ctx context.Context, r req) (*res, api.Err) {
+    err := doSomething()
+    if err != nil {
+        return nil, api.ErrFailure
+    }
+    return &res{"out1", true}, api.ErrSuccess
+}
+```
+
+If your handler signature does not match the configuration exactly, the server will print out the error and won't start.
+
+The `api.Err` type automatically maps to HTTP status codes and error descriptions that will be sent to the client as json; clients have to manage the same format for every response.
+```json
+{
+    "error": {
+        "code": 0,
+        "reason": "all right"
+    }
+}
+```
+
+## Changelog
 
 - [x] human-readable json configuration
-- [x] nested routes (*i.e. `/user/:id:` and `/user/post/:id:`*)
-- [x] nested URL arguments (*i.e. `/user/:id:` and `/user/:id:/post/​:id:​`*)
+- [x] nested routes (*i.e. `/user/{id}` and `/user/post/{id}`*)
+- [x] nested URL arguments (*i.e. `/user/{id}` and `/user/{uid}/post/​{id}`*)
 - [x] useful http methods: GET, POST, PUT, DELETE
-- [x] manage URL, query and body arguments:
-	- [x] multipart/form-data (variables and file uploads)
-	- [x] application/x-www-form-urlencoded
-	- [x] application/json
+    - [ ] add support for PATCH method
+    - [ ] add support for OPTIONS method
+        - [ ] it might be interesting to generate the list of allowed methods from the configuration
+        - [ ] add CORS support
+- [x] manage request data extraction:
+    - [x] URL slash-separated strings
+    - [x] HTTP Query named parameters
+        - [x] manage array format
+    - [x] body parameters
+        - [x] multipart/form-data (variables and file uploads)
+        - [x] application/x-www-form-urlencoded
+        - [x] application/json
 - [x] required vs. optional parameters with a default value
 - [x] parameter renaming
-- [x] generic type check (*i.e. implement custom types alongside built-in ones*)
-- [ ] built-in types
-	- [x] `any` - wildcard matching all values
-	- [x] `int` - see go types
-	- [x] `uint` - see go types
-	- [x] `float` - see go types
-	- [x] `string` - any text
-	- [x] `string(min, max)` - any string with a length between `min` and `max`
-	- [ ] `[a]` - array containing **only** elements matching `a` type
-	- [ ] `[a:b]` - map containing **only** keys of type `a` and values of type `b` (*a or b can be ommited*)
-- [x] generic controllers implementation (shared objects)
+- [x] generic type check (*i.e. you can add custom types alongside built-in ones*)
+- [x] built-in types
+    - [x] `any` - matches any value
+    - [x] `int` - see go types
+    - [x] `uint` - see go types
+    - [x] `float` - see go types
+    - [x] `string` - any text
+    - [x] `string(len)` - any string with a length of exactly `len` characters
+    - [x] `string(min, max)` - any string with a length between `min` and `max`
+    - [ ] `[]a` - array containing **only** elements matching `a` type
+    - [ ] `a[b]` - map containing **only** keys of type `a` and values of type `b` (*a or b can be ommited*)
+- [x] generic handler implementation
 - [x] response interface
-- [x] log bound resources when building the aicra server
-- [x] fail on check for unimplemented resources at server boot.
-- [x] fail on check for unavailable types in api.json at server boot.
+- [x] generic errors that automatically formats into response
+    - [x] builtin errors
+    - [x] possibility to add custom errors
+- [x] check for missing handlers when building the handler
+- [x] check handlers not matching a route in the configuration at server boot
+- [x] specific configuration format errors qt server boot
+- [x] statically typed handlers - avoids having to check every input and its type (_which is used by context.Context for instance_)
+    - [x] using reflection to use structs as input and output arguments to match the configuration
+        - [x] check for input and output arguments structs at server boot
+- [x] check for unavailable types in configuration at server boot
+- [x] recover panics from handlers
+- [ ] improve tests and coverage
+

api/auth.go

@@ -0,0 +1,62 @@
+package api
+
+// Auth can be used by http middleware to
+// 1) consult required roles in @Auth.Required
+// 2) update active roles in @Auth.Active
+type Auth struct {
+	// required roles for this request
+	// - the first dimension of the array reads as a OR
+	// - the second dimension reads as a AND
+	//
+	// Example:
+	// [ [A, B], [C, D] ] reads: roles (A and B) or (C and D) are required
+	//
+	// Warning: must not be mutated
+	Required [][]string
+
+	// active roles to be updated by authentication
+	// procedures (e.g. jwt)
+	Active []string
+}
+
+// Granted returns whether the authorization is granted
+// i.e. Auth.Active fulfills Auth.Required
+func (a *Auth) Granted() bool {
+	var nothingRequired = true
+
+	// first dimension: OR ; at least one is valid
+	for _, required := range a.Required {
+		// empty list
+		if len(required) < 1 {
+			continue
+		}
+
+		nothingRequired = false
+
+		// second dimension: AND ; all required must be fulfilled
+		if a.fulfills(required) {
+			return true
+		}
+	}
+
+	return nothingRequired
+}
+
+// returns whether Auth.Active fulfills (contains) all @required roles
+func (a *Auth) fulfills(required []string) bool {
+	for _, requiredRole := range required {
+		var found = false
+		for _, activeRole := range a.Active {
+			if activeRole == requiredRole {
+				found = true
+				break
+			}
+		}
+		// missing role -> fail
+		if !found {
+			return false
+		}
+	}
+	// all @required are fulfilled
+	return true
+}

api/auth_test.go

@@ -0,0 +1,114 @@
+package api
+
+import (
+	"testing"
+)
+
+func TestCombination(t *testing.T) {
+	tcases := []struct {
+		Name     string
+		Required [][]string
+		Active   []string
+		Granted  bool
+	}{
+		{
+			Name:     "no requirement none given",
+			Required: [][]string{},
+			Active:   []string{},
+			Granted:  true,
+		},
+		{
+			Name:     "empty requirements none given",
+			Required: [][]string{{}},
+			Active:   []string{},
+			Granted:  true,
+		},
+		{
+			Name:     "no requirement 1 given",
+			Required: [][]string{},
+			Active:   []string{"a"},
+			Granted:  true,
+		},
+		{
+			Name:     "no requirement some given",
+			Required: [][]string{},
+			Active:   []string{"a", "b"},
+			Granted:  true,
+		},
+
+		{
+			Name:     "1 required none given",
+			Required: [][]string{{"a"}},
+			Active:   []string{},
+			Granted:  false,
+		},
+		{
+			Name:     "1 required fulfilled",
+			Required: [][]string{{"a"}},
+			Active:   []string{"a"},
+			Granted:  true,
+		},
+		{
+			Name:     "1 required mismatch",
+			Required: [][]string{{"a"}},
+			Active:   []string{"b"},
+			Granted:  false,
+		},
+		{
+			Name:     "2 required none gien",
+			Required: [][]string{{"a", "b"}},
+			Active:   []string{},
+			Granted:  false,
+		},
+		{
+			Name:     "2 required other given",
+			Required: [][]string{{"a", "b"}},
+			Active:   []string{"c"},
+			Granted:  false,
+		},
+		{
+			Name:     "2 required one given",
+			Required: [][]string{{"a", "b"}},
+			Active:   []string{"a"},
+			Granted:  false,
+		},
+		{
+			Name:     "2 required fulfilled",
+			Required: [][]string{{"a", "b"}},
+			Active:   []string{"a", "b"},
+			Granted:  true,
+		},
+		{
+			Name:     "2 or 2 required first fulfilled",
+			Required: [][]string{{"a", "b"}, {"c", "d"}},
+			Active:   []string{"a", "b"},
+			Granted:  true,
+		},
+		{
+			Name:     "2 or 2 required second fulfilled",
+			Required: [][]string{{"a", "b"}, {"c", "d"}},
+			Active:   []string{"c", "d"},
+			Granted:  true,
+		},
+	}
+
+	for _, tcase := range tcases {
+		t.Run(tcase.Name, func(t *testing.T) {
+
+			auth := Auth{
+				Required: tcase.Required,
+				Active:   tcase.Active,
+			}
+
+			// all right
+			if tcase.Granted == auth.Granted() {
+				return
+			}
+
+			if tcase.Granted && !auth.Granted() {
+				t.Fatalf("expected granted authorization")
+			}
+			t.Fatalf("unexpected granted authorization")
+		})
+	}
+}

api/context.go

@@ -0,0 +1,44 @@
+package api
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/xdrm-io/aicra/internal/ctx"
+)
+
+// GetRequest extracts the current request from a context.Context
+func GetRequest(c context.Context) *http.Request {
+	var (
+		raw      = c.Value(ctx.Request)
+		cast, ok = raw.(*http.Request)
+	)
+	if !ok {
+		return nil
+	}
+	return cast
+}
+
+// GetResponseWriter extracts the response writer from a context.Context
+func GetResponseWriter(c context.Context) http.ResponseWriter {
+	var (
+		raw      = c.Value(ctx.Response)
+		cast, ok = raw.(http.ResponseWriter)
+	)
+	if !ok {
+		return nil
+	}
+	return cast
+}
+
+// GetAuth returns the api.Auth associated with this request from a context.Context
+func GetAuth(c context.Context) *Auth {
+	var (
+		raw      = c.Value(ctx.Auth)
+		cast, ok = raw.(*Auth)
+	)
+	if !ok {
+		return nil
+	}
+	return cast
+}

api/context_test.go

@@ -0,0 +1,79 @@
+package api_test
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/xdrm-io/aicra/api"
+	"github.com/xdrm-io/aicra/internal/ctx"
+)
+
+func TestContextGetRequest(t *testing.T) {
+	req, err := http.NewRequest(http.MethodGet, "/random", nil)
+	if err != nil {
+		t.Fatalf("cannot create http request: %s", err)
+	}
+
+	// store in bare context
+	c := context.Background()
+	c = context.WithValue(c, ctx.Request, req)
+
+	// fetch from context
+	fetched := api.GetRequest(c)
+	if fetched != req {
+		t.Fatalf("fetched http request %v ; expected %v", fetched, req)
+	}
+}
+func TestContextGetNilRequest(t *testing.T) {
+	// fetch from bare context
+	fetched := api.GetRequest(context.Background())
+	if fetched != nil {
+		t.Fatalf("fetched http request %v from empty context; expected nil", fetched)
+	}
+}
+
+func TestContextGetResponseWriter(t *testing.T) {
+	res := httptest.NewRecorder()
+
+	// store in bare context
+	c := context.Background()
+	c = context.WithValue(c, ctx.Response, res)
+
+	// fetch from context
+	fetched := api.GetResponseWriter(c)
+	if fetched != res {
+		t.Fatalf("fetched http response writer %v ; expected %v", fetched, res)
+	}
+}
+
+func TestContextGetNilResponseWriter(t *testing.T) {
+	// fetch from bare context
+	fetched := api.GetResponseWriter(context.Background())
+	if fetched != nil {
+		t.Fatalf("fetched http response writer %v from empty context; expected nil", fetched)
+	}
+}
+
+func TestContextGetAuth(t *testing.T) {
+	auth := &api.Auth{}
+
+	// store in bare context
+	c := context.Background()
+	c = context.WithValue(c, ctx.Auth, auth)
+
+	// fetch from context
+	fetched := api.GetAuth(c)
+	if fetched != auth {
+		t.Fatalf("fetched api auth %v ; expected %v", fetched, auth)
+	}
+}
+
+func TestContextGetNilAuth(t *testing.T) {
+	// fetch from bare context
+	fetched := api.GetAuth(context.Background())
+	if fetched != nil {
+		t.Fatalf("fetched api auth %v from empty context; expected nil", fetched)
+	}
+}

api/error.defaults.go

@@ -1,94 +1,84 @@
 package api
 
+import "net/http"
+
 var (
-	// ErrorUnknown represents any error which cause is unknown.
+	// ErrUnknown represents any error which cause is unknown.
 	// It might also be used for debug purposes as this error
 	// has to be used the less possible
-	ErrorUnknown Error = -1
+	ErrUnknown = Err{-1, "unknown error", http.StatusOK}
 
-	// ErrorSuccess represents a generic successful service execution
-	ErrorSuccess Error = 0
+	// ErrSuccess represents a generic successful service execution
+	ErrSuccess = Err{0, "all right", http.StatusOK}
 
-	// ErrorFailure is the most generic error
-	ErrorFailure Error = 1
+	// ErrFailure is the most generic error
+	ErrFailure = Err{1, "it failed", http.StatusInternalServerError}
 
-	// ErrorNoMatchFound has to be set when trying to fetch data and there is no result
-	ErrorNoMatchFound Error = 2
+	// ErrNoMatchFound is set when trying to fetch data and there is no result
+	ErrNoMatchFound = Err{2, "resource not found", http.StatusOK}
 
-	// ErrorAlreadyExists has to be set when trying to insert data, but identifiers or
+	// ErrAlreadyExists is set when trying to insert data, but identifiers or
 	// unique fields already exists
-	ErrorAlreadyExists Error = 3
+	ErrAlreadyExists = Err{3, "already exists", http.StatusOK}
 
-	// ErrorConfig has to be set when there is a configuration error
-	ErrorConfig Error = 4
+	// ErrCreation is set when there is a creation/insert error
+	ErrCreation = Err{4, "create error", http.StatusOK}
 
-	// ErrorUpload has to be set when a file upload failed
-	ErrorUpload Error = 100
+	// ErrModification is set when there is an update/modification error
+	ErrModification = Err{5, "update error", http.StatusOK}
 
-	// ErrorDownload has to be set when a file download failed
-	ErrorDownload Error = 101
+	// ErrDeletion is set when there is a deletion/removal error
+	ErrDeletion = Err{6, "delete error", http.StatusOK}
 
-	// MissingDownloadHeaders has to be set when the implementation
+	// ErrTransaction is set when there is a transactional error
+	ErrTransaction = Err{7, "transactional error", http.StatusOK}
+
+	// ErrUpload is set when a file upload failed
+	ErrUpload = Err{100, "upload failed", http.StatusInternalServerError}
+
+	// ErrDownload is set when a file download failed
+	ErrDownload = Err{101, "download failed", http.StatusInternalServerError}
+
+	// MissingDownloadHeaders is set when the implementation
 	// of a service of type 'download' (which returns a file instead of
 	// a set or output fields) is missing its HEADER field
-	MissingDownloadHeaders Error = 102
+	MissingDownloadHeaders = Err{102, "download headers are missing", http.StatusBadRequest}
 
-	// ErrorMissingDownloadBody has to be set when the implementation
+	// ErrMissingDownloadBody is set when the implementation
 	// of a service of type 'download' (which returns a file instead of
 	// a set or output fields) is missing its BODY field
-	ErrorMissingDownloadBody Error = 103
+	ErrMissingDownloadBody = Err{103, "download body is missing", http.StatusBadRequest}
 
-	// ErrorUnknownService is set when there is no service matching
+	// ErrUnknownService is set when there is no service matching
 	// the http request URI.
-	ErrorUnknownService Error = 200
+	ErrUnknownService = Err{200, "unknown service", http.StatusServiceUnavailable}
 
-	// ErrorUncallableService is set when there the requested service's
+	// ErrUncallableService is set when there the requested service's
 	// implementation (plugin file) is not found/callable
-	ErrorUncallableService Error = 202
+	ErrUncallableService = Err{202, "uncallable service", http.StatusServiceUnavailable}
 
-	// ErrorNotImplemented is set when a handler is not implemented yet
-	ErrorNotImplemented Error = 203
+	// ErrNotImplemented is set when a handler is not implemented yet
+	ErrNotImplemented = Err{203, "not implemented", http.StatusNotImplemented}
 
-	// ErrorPermission is set when there is a permission error by default
+	// ErrPermission is set when there is a permission error by default
 	// the api returns a permission error when the current scope (built
 	// by middlewares) does not match the scope required in the config.
 	// You can add your own permission policy and use this error
-	ErrorPermission Error = 300
+	ErrPermission = Err{300, "permission error", http.StatusUnauthorized}
 
-	// ErrorToken has to be set (usually in authentication middleware) to tell
+	// ErrToken is set (usually in authentication middleware) to tell
 	// the user that this authentication token is expired or invalid
-	ErrorToken Error = 301
+	ErrToken = Err{301, "token error", http.StatusForbidden}
 
-	// ErrorMissingParam is set when a *required* parameter is missing from the
+	// ErrMissingParam is set when a *required* parameter is missing from the
 	// http request
-	ErrorMissingParam Error = 400
+	ErrMissingParam = Err{400, "missing parameter", http.StatusBadRequest}
 
-	// ErrorInvalidParam is set when a given parameter fails its type check as
+	// ErrInvalidParam is set when a given parameter fails its type check as
 	// defined in the config file.
-	ErrorInvalidParam Error = 401
+	ErrInvalidParam = Err{401, "invalid parameter", http.StatusBadRequest}
 
-	// ErrorInvalidDefaultParam is set when an optional parameter's default value
+	// ErrInvalidDefaultParam is set when an optional parameter's default value
 	// does not match its type.
-	ErrorInvalidDefaultParam Error = 402
+	ErrInvalidDefaultParam = Err{402, "invalid default param", http.StatusBadRequest}
 )
-
-var errorReasons = map[Error]string{
-	ErrorUnknown:             "unknown error",
-	ErrorSuccess:             "all right",
-	ErrorFailure:             "it failed",
-	ErrorNoMatchFound:        "resource not found",
-	ErrorAlreadyExists:       "already exists",
-	ErrorConfig:              "configuration error",
-	ErrorUpload:              "upload failed",
-	ErrorDownload:            "download failed",
-	MissingDownloadHeaders:   "download headers are missing",
-	ErrorMissingDownloadBody: "download body is missing",
-	ErrorUnknownService:      "unknown service",
-	ErrorUncallableService:   "uncallable service",
-	ErrorNotImplemented:      "not implemented",
-	ErrorPermission:          "permission error",
-	ErrorToken:               "token error",
-	ErrorMissingParam:        "missing parameter",
-	ErrorInvalidParam:        "invalid parameter",
-	ErrorInvalidDefaultParam: "invalid default param",
-}

api/error.go

@@ -1,42 +1,21 @@
 package api
 
 import (
-	"encoding/json"
 	"fmt"
 )
 
-// Error represents an http response error following the api format.
+// Err represents an http response error following the api format.
 // These are used by the services to set the *execution status*
 // directly into the response as JSON alongside response output fields.
-type Error int
-
-// Error implements the error interface
-func (e Error) Error() string {
-	// use unknown error if no reason
-	reason, ok := errorReasons[e]
-	if !ok {
-		return ErrorUnknown.Error()
-	}
-
-	return fmt.Sprintf("[%d] %s", e, reason)
+type Err struct {
+	// error code (unique)
+	Code int `json:"code"`
+	// error small description
+	Reason string `json:"reason"`
+	// associated HTTP status
+	Status int `json:"-"`
 }
 
-// MarshalJSON implements encoding/json.Marshaler interface
-func (e Error) MarshalJSON() ([]byte, error) {
-	// use unknown error if no reason
-	reason, ok := errorReasons[e]
-	if !ok {
-		return ErrorUnknown.MarshalJSON()
-	}
-
-	// format to proper struct
-	formatted := struct {
-		Code   int    `json:"code"`
-		Reason string `json:"reason"`
-	}{
-		Code:   int(e),
-		Reason: reason,
-	}
-
-	return json.Marshal(formatted)
+func (e Err) Error() string {
+	return fmt.Sprintf("[%d] %s", e.Code, e.Reason)
 }

api/request.go

@@ -1,59 +0,0 @@
-package api
-
-import (
-	"net/http"
-	"strings"
-)
-
-// Request represents an API request i.e. HTTP
-type Request struct {
-	// corresponds to the list of uri components
-	//  featured in the request URI
-	URI []string
-
-	// Scope from the configuration file of the current service
-	Scope [][]string
-
-	// original HTTP request
-	Request *http.Request
-
-	// input parameters
-	Param RequestParam
-}
-
-// NewRequest builds an interface request from a http.Request
-func NewRequest(req *http.Request) (*Request, error) {
-
-	// 1. get useful data
-	uri := normaliseURI(req.URL.Path)
-	uriparts := strings.Split(uri, "/")
-
-	// 3. Init request
-	inst := &Request{
-		URI:     uriparts,
-		Scope:   nil,
-		Request: req,
-		Param:   make(RequestParam),
-	}
-
-	return inst, nil
-}
-
-// normaliseURI removes the trailing '/' to always
-// have the same Uri format for later processing
-func normaliseURI(uri string) string {
-
-	if len(uri) < 1 {
-		return uri
-	}
-
-	if uri[0] == '/' {
-		uri = uri[1:]
-	}
-
-	if len(uri) > 1 && uri[len(uri)-1] == '/' {
-		uri = uri[0 : len(uri)-1]
-	}
-
-	return uri
-}

api/request.param.go

@@ -1,162 +0,0 @@
-package api
-
-import (
-	"fmt"
-)
-
-// cerr allows you to create constant "const" error with type boxing.
-type cerr string
-
-// Error implements the error builtin interface.
-func (err cerr) Error() string {
-	return string(err)
-}
-
-// ErrReqParamNotFound is thrown when a request parameter is not found
-const ErrReqParamNotFound = cerr("request parameter not found")
-
-// ErrReqParamNotType is thrown when a request parameter is not asked with the right type
-const ErrReqParamNotType = cerr("request parameter does not fulfills type")
-
-// RequestParam defines input parameters of an api request
-type RequestParam map[string]interface{}
-
-// Get returns the raw value (not typed) and an error if not found
-func (rp RequestParam) Get(key string) (interface{}, error) {
-	rawValue, found := rp[key]
-	if !found {
-		return "", ErrReqParamNotFound
-	}
-	return rawValue, nil
-}
-
-// GetString returns a string and an error if not found or invalid type
-func (rp RequestParam) GetString(key string) (string, error) {
-	rawValue, err := rp.Get(key)
-	if err != nil {
-		return "", err
-	}
-
-	switch cast := rawValue.(type) {
-	case fmt.Stringer:
-		return cast.String(), nil
-	case []byte:
-		return string(cast), nil
-	case string:
-		return cast, nil
-	default:
-		return "", ErrReqParamNotType
-	}
-}
-
-// GetFloat returns a float64 and an error if not found or invalid type
-func (rp RequestParam) GetFloat(key string) (float64, error) {
-	rawValue, err := rp.Get(key)
-	if err != nil {
-		return 0, err
-	}
-
-	switch cast := rawValue.(type) {
-	case float32:
-		return float64(cast), nil
-	case float64:
-		return cast, nil
-	case int, int8, int16, int32, int64:
-		intVal, ok := cast.(int)
-		if !ok || intVal != int(float64(intVal)) {
-			return 0, ErrReqParamNotType
-		}
-		return float64(intVal), nil
-	case uint, uint8, uint16, uint32, uint64:
-		uintVal, ok := cast.(uint)
-		if !ok || uintVal != uint(float64(uintVal)) {
-			return 0, ErrReqParamNotType
-		}
-		return float64(uintVal), nil
-	default:
-		return 0, ErrReqParamNotType
-	}
-}
-
-// GetInt returns an int and an error if not found or invalid type
-func (rp RequestParam) GetInt(key string) (int, error) {
-	rawValue, err := rp.Get(key)
-	if err != nil {
-		return 0, err
-	}
-
-	switch cast := rawValue.(type) {
-	case float32, float64:
-		floatVal, ok := cast.(float64)
-		if !ok || floatVal < 0 || floatVal != float64(int(floatVal)) {
-			return 0, ErrReqParamNotType
-		}
-		return int(floatVal), nil
-	case int, int8, int16, int32, int64:
-		intVal, ok := cast.(int)
-		if !ok || intVal != int(int(intVal)) {
-			return 0, ErrReqParamNotType
-		}
-		return int(intVal), nil
-	default:
-		return 0, ErrReqParamNotType
-	}
-}
-
-// GetUint returns an uint and an error if not found or invalid type
-func (rp RequestParam) GetUint(key string) (uint, error) {
-	rawValue, err := rp.Get(key)
-	if err != nil {
-		return 0, err
-	}
-
-	switch cast := rawValue.(type) {
-	case float32, float64:
-		floatVal, ok := cast.(float64)
-		if !ok || floatVal < 0 || floatVal != float64(uint(floatVal)) {
-			return 0, ErrReqParamNotType
-		}
-		return uint(floatVal), nil
-	case int, int8, int16, int32, int64:
-		intVal, ok := cast.(int)
-		if !ok || intVal != int(uint(intVal)) {
-			return 0, ErrReqParamNotType
-		}
-		return uint(intVal), nil
-	case uint, uint8, uint16, uint32, uint64:
-		uintVal, ok := cast.(uint)
-		if !ok {
-			return 0, ErrReqParamNotType
-		}
-		return uintVal, nil
-	default:
-		return 0, ErrReqParamNotType
-	}
-}
-
-// GetStrings returns an []slice and an error if not found or invalid type
-func (rp RequestParam) GetStrings(key string) ([]string, error) {
-	rawValue, err := rp.Get(key)
-	if err != nil {
-		return nil, err
-	}
-
-	switch cast := rawValue.(type) {
-	case []fmt.Stringer:
-		strings := make([]string, len(cast))
-		for i, stringer := range cast {
-			strings[i] = stringer.String()
-		}
-		return strings, nil
-	case [][]byte:
-		strings := make([]string, len(cast))
-		for i, bytes := range cast {
-			strings[i] = string(bytes)
-		}
-		return strings, nil
-	case []string:
-		return cast, nil
-	default:
-		return nil, ErrReqParamNotType
-	}
-}

api/response.go

@@ -1,77 +0,0 @@
-package api
-
-import (
-	"encoding/json"
-	"net/http"
-)
-
-// ResponseData defines format for response parameters to return
-type ResponseData map[string]interface{}
-
-// Response represents an API response to be sent
-type Response struct {
-	Data    ResponseData
-	Status  int
-	Headers http.Header
-	err     Error
-}
-
-// EmptyResponse creates an empty response.
-func EmptyResponse() *Response {
-	return &Response{
-		Status:  http.StatusOK,
-		Data:    make(ResponseData),
-		err:     ErrorFailure,
-		Headers: make(http.Header),
-	}
-}
-
-// WithError sets the error from a base error with error arguments.
-func (res *Response) WithError(err Error) *Response {
-	res.err = err
-	return res
-}
-
-// Error implements the error interface and dispatches to internal error.
-func (res *Response) Error() string {
-	return res.err.Error()
-}
-
-// SetData adds/overrides a new response field
-func (res *Response) SetData(name string, value interface{}) {
-	res.Data[name] = value
-}
-
-// GetData gets a response field
-func (res *Response) GetData(name string) interface{} {
-	value, _ := res.Data[name]
-
-	return value
-}
-
-// MarshalJSON implements the 'json.Marshaler' interface and is used
-// to generate the JSON representation of the response
-func (res *Response) MarshalJSON() ([]byte, error) {
-	fmt := make(map[string]interface{})
-
-	for k, v := range res.Data {
-		fmt[k] = v
-	}
-
-	fmt["error"] = res.err
-
-	return json.Marshal(fmt)
-}
-
-// ServeHTTP implements http.Handler and writes the API response.
-func (res *Response) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
-	w.WriteHeader(res.Status)
-
-	encoded, err := json.Marshal(res)
-	if err != nil {
-		return err
-	}
-	w.Write(encoded)
-
-	return nil
-}

builder.go

@@ -0,0 +1,157 @@
+package aicra
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/xdrm-io/aicra/internal/config"
+	"github.com/xdrm-io/aicra/internal/dynfunc"
+	"github.com/xdrm-io/aicra/validator"
+)
+
+// Builder for an aicra server
+type Builder struct {
+	// the server configuration defining available services
+	conf *config.Server
+	// user-defined handlers bound to services from the configuration
+	handlers []*apiHandler
+	// http middlewares wrapping the entire http connection (e.g. logger)
+	middlewares []func(http.Handler) http.Handler
+	// custom middlewares only wrapping the service handler of a request
+	// they will benefit from the request's context that contains service-specific
+	// information (e.g. required permissions from the configuration)
+	ctxMiddlewares []func(http.Handler) http.Handler
+}
+
+// represents an api handler (method-pattern combination)
+type apiHandler struct {
+	Method string
+	Path   string
+	dyn    *dynfunc.Handler
+}
+
+// Validate adds an available Type to validate in the api definition
+func (b *Builder) Validate(t validator.Type) error {
+	if b.conf == nil {
+		b.conf = &config.Server{}
+	}
+	if b.conf.Services != nil {
+		return errLateType
+	}
+	if b.conf.Validators == nil {
+		b.conf.Validators = make([]validator.Type, 0)
+	}
+	b.conf.Validators = append(b.conf.Validators, t)
+	return nil
+}
+
+// With adds an http middleware on top of the http connection
+//
+// Authentication management can only be done with the WithContext() methods as
+// the service associated with the request has not been found at this stage.
+// This stage is perfect for logging or generic request management.
+func (b *Builder) With(mw func(http.Handler) http.Handler) {
+	if b.middlewares == nil {
+		b.middlewares = make([]func(http.Handler) http.Handler, 0)
+	}
+	b.middlewares = append(b.middlewares, mw)
+}
+
+// WithContext adds an http middleware with the fully loaded context
+//
+// Logging or generic request management should be done with the With() method as
+// it wraps the full http connection. Middlewares added through this method only
+// wrap the user-defined service handler. The context.Context is filled with useful
+// data that can be access with api.GetRequest(), api.GetResponseWriter(),
+// api.GetAuth(), etc methods.
+func (b *Builder) WithContext(mw func(http.Handler) http.Handler) {
+	if b.ctxMiddlewares == nil {
+		b.ctxMiddlewares = make([]func(http.Handler) http.Handler, 0)
+	}
+	b.ctxMiddlewares = append(b.ctxMiddlewares, mw)
+}
+
+// Setup the builder with its api definition file
+// panics if already setup
+func (b *Builder) Setup(r io.Reader) error {
+	if b.conf == nil {
+		b.conf = &config.Server{}
+	}
+	if b.conf.Services != nil {
+		return errAlreadySetup
+	}
+	return b.conf.Parse(r)
+}
+
+// Bind a dynamic handler to a REST service (method and pattern)
+func (b *Builder) Bind(method, path string, fn interface{}) error {
+	if b.conf == nil || b.conf.Services == nil {
+		return errNotSetup
+	}
+
+	// find associated service from config
+	var service *config.Service
+	for _, s := range b.conf.Services {
+		if method == s.Method && path == s.Pattern {
+			service = s
+			break
+		}
+	}
+
+	if service == nil {
+		return fmt.Errorf("%s '%s': %w", method, path, errUnknownService)
+	}
+
+	var dyn, err = dynfunc.Build(fn, *service)
+	if err != nil {
+		return fmt.Errorf("%s '%s' handler: %w", method, path, err)
+	}
+
+	b.handlers = append(b.handlers, &apiHandler{
+		Path:   path,
+		Method: method,
+		dyn:    dyn,
+	})
+
+	return nil
+}
+
+// Get is equivalent to Bind(http.MethodGet)
+func (b *Builder) Get(path string, fn interface{}) error {
+	return b.Bind(http.MethodGet, path, fn)
+}
+
+// Post is equivalent to Bind(http.MethodPost)
+func (b *Builder) Post(path string, fn interface{}) error {
+	return b.Bind(http.MethodPost, path, fn)
+}
+
+// Put is equivalent to Bind(http.MethodPut)
+func (b *Builder) Put(path string, fn interface{}) error {
+	return b.Bind(http.MethodPut, path, fn)
+}
+
+// Delete is equivalent to Bind(http.MethodDelete)
+func (b *Builder) Delete(path string, fn interface{}) error {
+	return b.Bind(http.MethodDelete, path, fn)
+}
+
+// Build a fully-featured HTTP server
+func (b Builder) Build() (http.Handler, error) {
+
+	for _, service := range b.conf.Services {
+		var isHandled bool
+		for _, handler := range b.handlers {
+			if handler.Method == service.Method && handler.Path == service.Pattern {
+				isHandled = true
+				break
+			}
+		}
+		if !isHandled {
+			return nil, fmt.Errorf("%s '%s': %w", service.Method, service.Pattern, errMissingHandler)
+		}
+	}
+
+	return Handler(b), nil
+}

builder_test.go

@@ -0,0 +1,439 @@
+package aicra
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/xdrm-io/aicra/api"
+	"github.com/xdrm-io/aicra/internal/dynfunc"
+	"github.com/xdrm-io/aicra/validator"
+)
+
+func addBuiltinTypes(b *Builder) error {
+	if err := b.Validate(validator.AnyType{}); err != nil {
+		return err
+	}
+	if err := b.Validate(validator.BoolType{}); err != nil {
+		return err
+	}
+	if err := b.Validate(validator.FloatType{}); err != nil {
+		return err
+	}
+	if err := b.Validate(validator.IntType{}); err != nil {
+		return err
+	}
+	if err := b.Validate(validator.StringType{}); err != nil {
+		return err
+	}
+	if err := b.Validate(validator.UintType{}); err != nil {
+		return err
+	}
+	return nil
+}
+
+func TestAddType(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Validate(validator.BoolType{})
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	err = builder.Setup(strings.NewReader("[]"))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	err = builder.Validate(validator.FloatType{})
+	if err != errLateType {
+		t.Fatalf("expected <%v> got <%v>", errLateType, err)
+	}
+}
+
+func TestSetupNoType(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Setup(strings.NewReader("[]"))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+}
+func TestSetupTwice(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Setup(strings.NewReader("[]"))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	// double Setup() must fail
+	err = builder.Setup(strings.NewReader("[]"))
+	if err != errAlreadySetup {
+		t.Fatalf("expected error %v, got %v", errAlreadySetup, err)
+	}
+}
+
+func TestBindBeforeSetup(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	// binding before Setup() must fail
+	err := builder.Bind(http.MethodGet, "/path", func() {})
+	if err != errNotSetup {
+		t.Fatalf("expected error %v, got %v", errNotSetup, err)
+	}
+}
+
+func TestBindUnknownService(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Setup(strings.NewReader("[]"))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	err = builder.Bind(http.MethodGet, "/path", func() {})
+	if !errors.Is(err, errUnknownService) {
+		t.Fatalf("expected error %v, got %v", errUnknownService, err)
+	}
+}
+func TestBindInvalidHandler(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Setup(strings.NewReader(`[
+		{
+			"method": "GET",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		}
+	]`))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+	err = builder.Bind(http.MethodGet, "/path", func() {})
+
+	if err == nil {
+		t.Fatalf("expected an error")
+	}
+
+	if !errors.Is(err, dynfunc.ErrMissingHandlerContextArgument) {
+		t.Fatalf("expected a dynfunc.Err got %v", err)
+	}
+}
+func TestBindGet(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Setup(strings.NewReader(`[
+		{
+			"method": "GET",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		},
+		{
+			"method": "POST",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		},
+		{
+			"method": "PUT",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		},
+		{
+			"method": "DELETE",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		}
+	]`))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	err = builder.Get("/path", func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess })
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+	err = builder.Post("/path", func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess })
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+	err = builder.Put("/path", func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess })
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+	err = builder.Delete("/path", func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess })
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+}
+
+func TestUnhandledService(t *testing.T) {
+	t.Parallel()
+
+	builder := &Builder{}
+	err := builder.Setup(strings.NewReader(`[
+		{
+			"method": "GET",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		},
+		{
+			"method": "POST",
+			"path": "/path",
+			"scope": [[]],
+			"info": "info",
+			"in": {},
+			"out": {}
+		}
+	]`))
+	if err != nil {
+		t.Fatalf("unexpected error: %s", err)
+	}
+
+	err = builder.Get("/path", func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess })
+	if err != nil {
+		t.Fatalf("unexpected error %v", err)
+	}
+
+	_, err = builder.Build()
+	if !errors.Is(err, errMissingHandler) {
+		t.Fatalf("expected a %v error, got %v", errMissingHandler, err)
+	}
+}
+func TestBind(t *testing.T) {
+	t.Parallel()
+
+	tcases := []struct {
+		Name          string
+		Config        string
+		HandlerMethod string
+		HandlerPath   string
+		HandlerFn     interface{} // not bound if nil
+		BindErr       error
+		BuildErr      error
+	}{
+		{
+			Name:          "none required none provided",
+			Config:        "[]",
+			HandlerMethod: "",
+			HandlerPath:   "",
+			HandlerFn:     nil,
+			BindErr:       nil,
+			BuildErr:      nil,
+		},
+		{
+			Name:          "none required 1 provided",
+			Config:        "[]",
+			HandlerMethod: "",
+			HandlerPath:   "",
+			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       errUnknownService,
+			BuildErr:      nil,
+		},
+		{
+			Name: "1 required none provided",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: "",
+			HandlerPath:   "",
+			HandlerFn:     nil,
+			BindErr:       nil,
+			BuildErr:      errMissingHandler,
+		},
+		{
+			Name: "1 required wrong method provided",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodPost,
+			HandlerPath:   "/path",
+			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       errUnknownService,
+			BuildErr:      errMissingHandler,
+		},
+		{
+			Name: "1 required wrong path provided",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodGet,
+			HandlerPath:   "/paths",
+			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       errUnknownService,
+			BuildErr:      errMissingHandler,
+		},
+		{
+			Name: "1 required valid provided",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodGet,
+			HandlerPath:   "/path",
+			HandlerFn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       nil,
+			BuildErr:      nil,
+		},
+		{
+			Name: "1 required with int",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {
+						"id": { "info": "info", "type": "int", "name": "Name" }
+					},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodGet,
+			HandlerPath:   "/path",
+			HandlerFn:     func(context.Context, struct{ Name int }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       nil,
+			BuildErr:      nil,
+		},
+		{
+			Name: "1 required with uint",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {
+						"id": { "info": "info", "type": "uint", "name": "Name" }
+					},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodGet,
+			HandlerPath:   "/path",
+			HandlerFn:     func(context.Context, struct{ Name uint }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       nil,
+			BuildErr:      nil,
+		},
+		{
+			Name: "1 required with string",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {
+						"id": { "info": "info", "type": "string", "name": "Name" }
+					},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodGet,
+			HandlerPath:   "/path",
+			HandlerFn:     func(context.Context, struct{ Name string }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       nil,
+			BuildErr:      nil,
+		},
+		{
+			Name: "1 required with bool",
+			Config: `[
+				{
+					"method": "GET",
+					"path": "/path",
+					"scope": [[]],
+					"info": "info",
+					"in": {
+						"id": { "info": "info", "type": "bool", "name": "Name" }
+					},
+					"out": {}
+				}
+			]`,
+			HandlerMethod: http.MethodGet,
+			HandlerPath:   "/path",
+			HandlerFn:     func(context.Context, struct{ Name bool }) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			BindErr:       nil,
+			BuildErr:      nil,
+		},
+	}
+
+	for _, tcase := range tcases {
+		t.Run(tcase.Name, func(t *testing.T) {
+			t.Parallel()
+
+			builder := &Builder{}
+
+			if err := addBuiltinTypes(builder); err != nil {
+				t.Fatalf("add built-in types: %s", err)
+			}
+
+			err := builder.Setup(strings.NewReader(tcase.Config))
+			if err != nil {
+				t.Fatalf("setup: unexpected error <%v>", err)
+			}
+
+			if tcase.HandlerFn != nil {
+				err := builder.Bind(tcase.HandlerMethod, tcase.HandlerPath, tcase.HandlerFn)
+				if !errors.Is(err, tcase.BindErr) {
+					t.Fatalf("bind: expected <%v> got <%v>", tcase.BindErr, err)
+				}
+			}
+
+			_, err = builder.Build()
+			if !errors.Is(err, tcase.BuildErr) {
+				t.Fatalf("build: expected <%v> got <%v>", tcase.BuildErr, err)
+			}
+
+		})
+	}
+}

datatype/builtin/any.go

@@ -1,26 +0,0 @@
-package builtin
-
-import (
-	"reflect"
-
-	"git.xdrm.io/go/aicra/datatype"
-)
-
-// AnyDataType is what its name tells
-type AnyDataType struct{}
-
-// Type returns the type of data
-func (AnyDataType) Type() reflect.Type {
-	return reflect.TypeOf(interface{}(nil))
-}
-
-// Build returns the validator
-func (AnyDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
-	// nothing if type not handled
-	if typeName != "any" {
-		return nil
-	}
-	return func(value interface{}) (interface{}, bool) {
-		return value, true
-	}
-}

datatype/types.go

@@ -1,15 +0,0 @@
-package datatype
-
-import "reflect"
-
-// Validator returns whether a given value fulfills a datatype
-// and casts the value into a compatible type
-type Validator func(value interface{}) (cast interface{}, valid bool)
-
-// T builds a T from the type definition (from the configuration field "type") and returns NIL if the type
-// definition does not match this T ; the registry is passed for recursive datatypes (e.g. slices, structs, etc)
-// to be able to access other datatypes
-type T interface {
-	Type() reflect.Type
-	Build(typeDefinition string, registry ...T) Validator
-}

dynamic/errors.go

@@ -1,48 +0,0 @@
-package dynamic
-
-// cerr allows you to create constant "const" error with type boxing.
-type cerr string
-
-// Error implements the error builtin interface.
-func (err cerr) Error() string {
-	return string(err)
-}
-
-// ErrHandlerNotFunc - handler is not a func
-const ErrHandlerNotFunc = cerr("handler must be a func")
-
-// ErrNoServiceForHandler - no service matching this handler
-const ErrNoServiceForHandler = cerr("no service found for this handler")
-
-// ErrMissingHandlerArgumentParam - missing params arguments for handler
-const ErrMissingHandlerArgumentParam = cerr("missing handler argument : parameter struct")
-
-// ErrMissingHandlerOutput - missing output for handler
-const ErrMissingHandlerOutput = cerr("handler must have at least 1 output")
-
-// ErrMissingHandlerOutputError - missing error output for handler
-const ErrMissingHandlerOutputError = cerr("handler must have its last output of type api.Error")
-
-// ErrMissingRequestArgument - missing request argument for handler
-const ErrMissingRequestArgument = cerr("handler first argument must be of type api.Request")
-
-// ErrMissingParamArgument - missing parameters argument for handler
-const ErrMissingParamArgument = cerr("handler second argument must be a struct")
-
-// ErrMissingParamOutput - missing output argument for handler
-const ErrMissingParamOutput = cerr("handler first output must be a *struct")
-
-// ErrMissingParamFromConfig - missing a parameter in handler struct
-const ErrMissingParamFromConfig = cerr("missing a parameter from configuration")
-
-// ErrMissingOutputFromConfig - missing a parameter in handler struct
-const ErrMissingOutputFromConfig = cerr("missing a parameter from configuration")
-
-// ErrWrongParamTypeFromConfig - a configuration parameter type is invalid in the handler param struct
-const ErrWrongParamTypeFromConfig = cerr("invalid struct field type")
-
-// ErrWrongOutputTypeFromConfig - a configuration output type is invalid in the handler output struct
-const ErrWrongOutputTypeFromConfig = cerr("invalid struct field type")
-
-// ErrMissingHandlerErrorOutput - missing handler output error
-const ErrMissingHandlerErrorOutput = cerr("last output must be of type api.Error")

dynamic/handler.go

@@ -1,90 +0,0 @@
-package dynamic
-
-import (
-	"fmt"
-	"reflect"
-
-	"git.xdrm.io/go/aicra/api"
-	"git.xdrm.io/go/aicra/internal/config"
-)
-
-// Build a handler from a service configuration and a HandlerFn
-//
-// a HandlerFn must have as a signature : `func(api.Request, inputStruct) (outputStruct, api.Error)`
-//  - `inputStruct` is a struct{} containing a field for each service input (with valid reflect.Type)
-//  - `outputStruct` is a struct{} containing a field for each service output (with valid reflect.Type)
-//
-// Special cases:
-//  - it there is no input, `inputStruct` can be omitted
-//  - it there is no output, `outputStruct` can be omitted
-func Build(fn HandlerFn, service config.Service) (*Handler, error) {
-	h := &Handler{
-		spec: makeSpec(service),
-		fn:   fn,
-	}
-
-	fnv := reflect.ValueOf(fn)
-
-	if fnv.Type().Kind() != reflect.Func {
-		return nil, ErrHandlerNotFunc
-	}
-
-	if err := h.spec.checkInput(fnv); err != nil {
-		return nil, fmt.Errorf("input: %w", err)
-	}
-	if err := h.spec.checkOutput(fnv); err != nil {
-		return nil, fmt.Errorf("output: %w", err)
-	}
-
-	return h, nil
-}
-
-// Handle binds input @data into HandleFn and returns map output
-func (h *Handler) Handle(data map[string]interface{}) (map[string]interface{}, api.Error) {
-	fnv := reflect.ValueOf(h.fn)
-
-	callArgs := []reflect.Value{}
-
-	// bind input data
-	if fnv.Type().NumIn() > 0 {
-		// create zero value struct
-		callStructPtr := reflect.New(fnv.Type().In(0))
-		callStruct := callStructPtr.Elem()
-
-		// set each field
-		for name := range h.spec.Input {
-			field := callStruct.FieldByName(name)
-			if !field.CanSet() {
-				continue
-			}
-
-			// get value from @data
-			value, inData := data[name]
-			if !inData {
-				continue
-			}
-			field.Set(reflect.ValueOf(value).Convert(field.Type()))
-		}
-		callArgs = append(callArgs, callStruct)
-	}
-
-	// call the HandlerFn
-	output := fnv.Call(callArgs)
-
-	// no output OR pointer to output struct is nil
-	outdata := make(map[string]interface{})
-	if len(h.spec.Output) < 1 || output[0].IsNil() {
-		return outdata, api.Error(output[len(output)-1].Int())
-	}
-
-	// extract struct from pointer
-	returnStruct := output[0].Elem()
-
-	for name := range h.spec.Output {
-		field := returnStruct.FieldByName(name)
-		outdata[name] = field.Interface()
-	}
-
-	// extract api.Error
-	return outdata, api.Error(output[len(output)-1].Int())
-}

dynamic/spec.go

@@ -1,119 +0,0 @@
-package dynamic
-
-import (
-	"fmt"
-	"reflect"
-
-	"git.xdrm.io/go/aicra/api"
-	"git.xdrm.io/go/aicra/internal/config"
-)
-
-// builds a spec from the configuration service
-func makeSpec(service config.Service) spec {
-	spec := spec{
-		Input:  make(map[string]reflect.Type),
-		Output: make(map[string]reflect.Type),
-	}
-
-	for _, param := range service.Input {
-		// make a pointer if optional
-		if param.Optional {
-			spec.Input[param.Rename] = reflect.PtrTo(param.ExtractType)
-			continue
-		}
-		spec.Input[param.Rename] = param.ExtractType
-	}
-
-	for _, param := range service.Output {
-		spec.Output[param.Rename] = param.ExtractType
-	}
-
-	return spec
-}
-
-// checks for HandlerFn input arguments
-func (s spec) checkInput(fnv reflect.Value) error {
-	fnt := fnv.Type()
-
-	// no input -> ok
-	if len(s.Input) == 0 {
-		return nil
-	}
-
-	if fnt.NumIn() != 1 {
-		return ErrMissingHandlerArgumentParam
-	}
-
-	// arg must be a struct
-	structArg := fnt.In(0)
-	if structArg.Kind() != reflect.Struct {
-		return ErrMissingParamArgument
-	}
-
-	// check for invlaid param
-	for name, ptype := range s.Input {
-		field, exists := structArg.FieldByName(name)
-		if !exists {
-			return fmt.Errorf("%s: %w", name, ErrMissingParamFromConfig)
-		}
-
-		if !ptype.AssignableTo(field.Type) {
-			return fmt.Errorf("%s: %w (%s instead of %s)", name, ErrWrongParamTypeFromConfig, field.Type, ptype)
-		}
-	}
-
-	return nil
-}
-
-// checks for HandlerFn output arguments
-func (s spec) checkOutput(fnv reflect.Value) error {
-	fnt := fnv.Type()
-	if fnt.NumOut() < 1 {
-		return ErrMissingHandlerOutput
-	}
-
-	// last output must be api.Error
-	errOutput := fnt.Out(fnt.NumOut() - 1)
-	if !errOutput.AssignableTo(reflect.TypeOf(api.ErrorUnknown)) {
-		return ErrMissingHandlerErrorOutput
-	}
-
-	// no output -> ok
-	if len(s.Output) == 0 {
-		return nil
-	}
-
-	if fnt.NumOut() != 2 {
-		return ErrMissingParamOutput
-	}
-
-	// fail if first output is not a pointer to struct
-	structOutputPtr := fnt.Out(0)
-	if structOutputPtr.Kind() != reflect.Ptr {
-		return ErrMissingParamOutput
-	}
-
-	structOutput := structOutputPtr.Elem()
-	if structOutput.Kind() != reflect.Struct {
-		return ErrMissingParamOutput
-	}
-
-	// fail on invalid output
-	for name, ptype := range s.Output {
-		field, exists := structOutput.FieldByName(name)
-		if !exists {
-			return fmt.Errorf("%s: %w", name, ErrMissingOutputFromConfig)
-		}
-
-		// ignore types evalutating to nil
-		if ptype == nil {
-			continue
-		}
-
-		if !ptype.ConvertibleTo(field.Type) {
-			return fmt.Errorf("%s: %w (%s instead of %s)", name, ErrWrongOutputTypeFromConfig, field.Type, ptype)
-		}
-	}
-
-	return nil
-}

dynamic/types.go

@@ -1,17 +0,0 @@
-package dynamic
-
-import "reflect"
-
-// HandlerFn defines a dynamic handler function
-type HandlerFn interface{}
-
-// Handler represents a dynamic api handler
-type Handler struct {
-	spec spec
-	fn   HandlerFn
-}
-
-type spec struct {
-	Input  map[string]reflect.Type
-	Output map[string]reflect.Type
-}

errors.go

@@ -3,13 +3,21 @@ package aicra
 // cerr allows you to create constant "const" error with type boxing.
 type cerr string
 
-// Error implements the error builtin interface.
 func (err cerr) Error() string {
 	return string(err)
 }
 
-// ErrNoServiceForHandler - no service matching this handler
-const ErrNoServiceForHandler = cerr("no service found for this handler")
+// errLateType - cannot add datatype after setting up the definition
+const errLateType = cerr("types cannot be added after Setup")
 
-// ErrNoHandlerForService - no handler matching this service
-const ErrNoHandlerForService = cerr("no handler found for this service")
+// errNotSetup - not set up yet
+const errNotSetup = cerr("not set up")
+
+// errAlreadySetup - already set up
+const errAlreadySetup = cerr("already set up")
+
+// errUnknownService - no service matching this handler
+const errUnknownService = cerr("unknown service")
+
+// errMissingHandler - missing handler
+const errMissingHandler = cerr("missing handler")

go.mod

@@ -1,3 +1,3 @@
-module git.xdrm.io/go/aicra
+module github.com/xdrm-io/aicra
 
-go 1.14
+go 1.16

handler.go

@@ -1,32 +1,174 @@
 package aicra
 
 import (
+	"context"
+	"errors"
 	"fmt"
+	"net/http"
 	"strings"
 
-	"git.xdrm.io/go/aicra/dynamic"
-	"git.xdrm.io/go/aicra/internal/config"
+	"github.com/xdrm-io/aicra/api"
+	"github.com/xdrm-io/aicra/internal/config"
+	"github.com/xdrm-io/aicra/internal/ctx"
+	"github.com/xdrm-io/aicra/internal/reqdata"
 )
 
-type handler struct {
-	Method     string
-	Path       string
-	dynHandler *dynamic.Handler
+// Handler wraps the builder to handle requests
+type Handler Builder
+
+// ServeHTTP implements http.Handler and wraps it in middlewares (adapters)
+func (s Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var h http.Handler = http.HandlerFunc(s.resolve)
+
+	for _, mw := range s.middlewares {
+		h = mw(h)
+	}
+	h.ServeHTTP(w, r)
 }
 
-// createHandler builds a handler from its http method and path
-// also it checks whether the function signature is valid
-func createHandler(method, path string, service config.Service, fn dynamic.HandlerFn) (*handler, error) {
-	method = strings.ToUpper(method)
-
-	dynHandler, err := dynamic.Build(fn, service)
-	if err != nil {
-		return nil, fmt.Errorf("%s '%s' handler: %w", method, path, err)
+// ServeHTTP implements http.Handler and wraps it in middlewares (adapters)
+func (s Handler) resolve(w http.ResponseWriter, r *http.Request) {
+	// match service from config
+	var service = s.conf.Find(r)
+	if service == nil {
+		newResponse().WithError(api.ErrUnknownService).ServeHTTP(w, r)
+		return
 	}
 
-	return &handler{
-		Path:       path,
-		Method:     method,
-		dynHandler: dynHandler,
-	}, nil
+	// extract request data
+	var input, err = extractInput(service, *r)
+	if err != nil {
+		if errors.Is(err, reqdata.ErrInvalidType) {
+			newResponse().WithError(api.ErrInvalidParam).ServeHTTP(w, r)
+		} else {
+			newResponse().WithError(api.ErrMissingParam).ServeHTTP(w, r)
+		}
+		return
+	}
+
+	// match handler
+	var handler *apiHandler
+	for _, h := range s.handlers {
+		if h.Method == service.Method && h.Path == service.Pattern {
+			handler = h
+		}
+	}
+
+	// no handler found
+	if handler == nil {
+		newResponse().WithError(api.ErrUncallableService).ServeHTTP(w, r)
+		return
+	}
+
+	// add info into context
+	c := r.Context()
+	c = context.WithValue(c, ctx.Request, r)
+	c = context.WithValue(c, ctx.Response, w)
+	c = context.WithValue(c, ctx.Auth, buildAuth(service.Scope, input.Data))
+
+	// create http handler
+	var h http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// should not happen
+		auth := api.GetAuth(r.Context())
+		if auth == nil {
+			newResponse().WithError(api.ErrPermission).ServeHTTP(w, r)
+			return
+		}
+
+		// reject non granted requests
+		if !auth.Granted() {
+			newResponse().WithError(api.ErrPermission).ServeHTTP(w, r)
+			return
+		}
+
+		// execute the service handler
+		s.handle(r.Context(), input, handler, service, w, r)
+	})
+
+	// run contextual middlewares
+	for _, mw := range s.ctxMiddlewares {
+		h = mw(h)
+	}
+
+	// serve using the pre-filled context
+	h.ServeHTTP(w, r.WithContext(c))
+}
+
+// handle the service request with the associated handler func and respond using
+// the handler func output
+func (s *Handler) handle(c context.Context, input *reqdata.T, handler *apiHandler, service *config.Service, w http.ResponseWriter, r *http.Request) {
+	// pass execution to the handler function
+	var outData, outErr = handler.dyn.Handle(c, input.Data)
+
+	// build response from output arguments
+	var res = newResponse().WithError(outErr)
+	for key, value := range outData {
+
+		// find original name from 'rename' field
+		for name, param := range service.Output {
+			if param.Rename == key {
+				res.WithValue(name, value)
+			}
+		}
+	}
+
+	// write response and close request
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	res.ServeHTTP(w, r)
+}
+
+func extractInput(service *config.Service, req http.Request) (*reqdata.T, error) {
+	var dataset = reqdata.New(service)
+
+	// URI data
+	var err = dataset.GetURI(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// query data
+	err = dataset.GetQuery(req)
+	if err != nil {
+		return nil, err
+	}
+
+	// form/json data
+	err = dataset.GetForm(req)
+	if err != nil {
+		return nil, err
+	}
+
+	return dataset, nil
+}
+
+// buildAuth builds the api.Auth struct from the service scope configuration
+//
+// it replaces format '[a]' in scope where 'a' is an existing input argument's
+// name with its value
+func buildAuth(scope [][]string, in map[string]interface{}) *api.Auth {
+	updated := make([][]string, len(scope))
+
+	// replace '[arg_name]' with the 'arg_name' value if it is a known variable
+	// name
+	for a, list := range scope {
+		updated[a] = make([]string, len(list))
+		for b, perm := range list {
+			updated[a][b] = perm
+			for name, value := range in {
+				var (
+					token       = fmt.Sprintf("[%s]", name)
+					replacement = ""
+				)
+				if value != nil {
+					replacement = fmt.Sprintf("[%v]", value)
+				}
+				updated[a][b] = strings.ReplaceAll(updated[a][b], token, replacement)
+			}
+		}
+	}
+
+	return &api.Auth{
+		Required: updated,
+		Active:   []string{},
+	}
 }

http.go

@@ -1,116 +0,0 @@
-package aicra
-
-import (
-	"log"
-	"net/http"
-
-	"git.xdrm.io/go/aicra/api"
-	"git.xdrm.io/go/aicra/internal/reqdata"
-)
-
-// httpServer wraps the aicra server to allow handling http requests
-type httpServer Server
-
-// ServeHTTP implements http.Handler and has to be called on each request
-func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
-	defer req.Body.Close()
-
-	// 1. find a matching service in the config
-	service := server.config.Find(req)
-	if service == nil {
-		response := api.EmptyResponse().WithError(api.ErrorUnknownService)
-		response.ServeHTTP(res, req)
-		logError(response)
-		return
-	}
-
-	// 2. build input parameter receiver
-	dataset := reqdata.New(service)
-
-	// 3. extract URI data
-	err := dataset.ExtractURI(req)
-	if err != nil {
-		response := api.EmptyResponse().WithError(api.ErrorMissingParam)
-		response.ServeHTTP(res, req)
-		logError(response)
-		return
-	}
-
-	// 4. extract query data
-	err = dataset.ExtractQuery(req)
-	if err != nil {
-		response := api.EmptyResponse().WithError(api.ErrorMissingParam)
-		response.ServeHTTP(res, req)
-		logError(response)
-		return
-	}
-
-	// 5. extract form/json data
-	err = dataset.ExtractForm(req)
-	if err != nil {
-		response := api.EmptyResponse().WithError(api.ErrorMissingParam)
-		response.ServeHTTP(res, req)
-		logError(response)
-		return
-	}
-
-	// 6. find a matching handler
-	var foundHandler *handler
-	var found bool
-
-	for _, handler := range server.handlers {
-		if handler.Method == service.Method && handler.Path == service.Pattern {
-			foundHandler = handler
-			found = true
-		}
-	}
-
-	// 7. fail if found no handler
-	if foundHandler == nil {
-		if found {
-			r := api.EmptyResponse().WithError(api.ErrorUncallableService)
-			r.ServeHTTP(res, req)
-			logError(r)
-			return
-		}
-
-		r := api.EmptyResponse().WithError(api.ErrorUnknownService)
-		r.ServeHTTP(res, req)
-		logError(r)
-		return
-	}
-
-	// 8. build api.Request from http.Request
-	apireq, err := api.NewRequest(req)
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	// 9. feed request with scope & parameters
-	apireq.Scope = service.Scope
-	apireq.Param = dataset.Data
-
-	// 10. execute
-	returned, apiErr := foundHandler.dynHandler.Handle(dataset.Data)
-	response := api.EmptyResponse().WithError(apiErr)
-	for key, value := range returned {
-
-		// find original name from rename
-		for name, param := range service.Output {
-			if param.Rename == key {
-				response.SetData(name, value)
-			}
-		}
-	}
-
-	// 11. apply headers
-	res.Header().Set("Content-Type", "application/json; charset=utf-8")
-	for key, values := range response.Headers {
-		for _, value := range values {
-			res.Header().Add(key, value)
-		}
-	}
-
-	// 12. write to response
-	response.ServeHTTP(res, req)
-}

internal/config/config.go

@@ -0,0 +1,182 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+
+	"github.com/xdrm-io/aicra/validator"
+)
+
+// Server definition
+type Server struct {
+	Validators []validator.Type
+	Services   []*Service
+}
+
+// Parse a configuration into a server. Server.Types must be set beforehand to
+// make datatypes available when checking and formatting the read configuration.
+func (s *Server) Parse(r io.Reader) error {
+	err := json.NewDecoder(r).Decode(&s.Services)
+	if err != nil {
+		return fmt.Errorf("%s: %w", ErrRead, err)
+	}
+
+	err = s.validate()
+	if err != nil {
+		return fmt.Errorf("%s: %w", ErrFormat, err)
+	}
+	return nil
+}
+
+// validate implements the validator interface
+func (s Server) validate(datatypes ...validator.Type) error {
+	for _, service := range s.Services {
+		err := service.validate(s.Validators...)
+		if err != nil {
+			return fmt.Errorf("%s '%s': %w", service.Method, service.Pattern, err)
+		}
+	}
+
+	if err := s.collide(); err != nil {
+		return fmt.Errorf("%s: %w", ErrFormat, err)
+	}
+	return nil
+}
+
+// Find a service matching an incoming HTTP request
+func (s Server) Find(r *http.Request) *Service {
+	for _, service := range s.Services {
+		if matches := service.Match(r); matches {
+			return service
+		}
+	}
+
+	return nil
+}
+
+// collide returns if there is collision between any service for the same method and colliding paths.
+// Note that service path collision detection relies on datatypes:
+//  - example 1: `/user/{id}` and `/user/articles` will not collide as {id} is an int and "articles" is not
+//  - example 2: `/user/{name}` and `/user/articles` will collide as {name} is a string so as "articles"
+//  - example 3: `/user/{name}` and `/user/{id}` will collide as {name} and {id} cannot be checked against their potential values
+func (s *Server) collide() error {
+	length := len(s.Services)
+
+	// for each service combination
+	for a := 0; a < length; a++ {
+		for b := a + 1; b < length; b++ {
+			aService := s.Services[a]
+			bService := s.Services[b]
+
+			if aService.Method != bService.Method {
+				continue
+			}
+
+			aURIParts := SplitURL(aService.Pattern)
+			bURIParts := SplitURL(bService.Pattern)
+			if len(aURIParts) != len(bURIParts) {
+				continue
+			}
+
+			err := checkURICollision(aURIParts, bURIParts, aService.Input, bService.Input)
+			if err != nil {
+				return fmt.Errorf("(%s '%s') vs (%s '%s'): %w", aService.Method, aService.Pattern, bService.Method, bService.Pattern, err)
+			}
+		}
+	}
+
+	return nil
+}
+
+// check if uri of services A and B collide
+func checkURICollision(uriA, uriB []string, inputA, inputB map[string]*Parameter) error {
+	var errors = []error{}
+
+	// for each part
+	for pi, aPart := range uriA {
+		bPart := uriB[pi]
+
+		// no need for further check as it has been done earlier in the validation process
+		aIsCapture := len(aPart) > 1 && aPart[0] == '{'
+		bIsCapture := len(bPart) > 1 && bPart[0] == '{'
+
+		// both captures -> as we cannot check, consider a collision
+		if aIsCapture && bIsCapture {
+			errors = append(errors, fmt.Errorf("%w (path %s and %s)", ErrPatternCollision, aPart, bPart))
+			continue
+		}
+
+		// no capture -> check strict equality
+		if !aIsCapture && !bIsCapture {
+			if aPart == bPart {
+				errors = append(errors, fmt.Errorf("%w (same path '%s')", ErrPatternCollision, aPart))
+				continue
+			}
+		}
+
+		// A captures B -> check type (B is A ?)
+		if aIsCapture {
+			input, exists := inputA[aPart]
+
+			// fail if no type or no validator
+			if !exists || input.Validator == nil {
+				errors = append(errors, fmt.Errorf("%w (invalid type for %s)", ErrPatternCollision, aPart))
+				continue
+			}
+
+			// fail if not valid
+			if _, valid := input.Validator(bPart); valid {
+				errors = append(errors, fmt.Errorf("%w (%s captures '%s')", ErrPatternCollision, aPart, bPart))
+				continue
+			}
+
+			// B captures A -> check type (A is B ?)
+		} else if bIsCapture {
+			input, exists := inputB[bPart]
+
+			// fail if no type or no validator
+			if !exists || input.Validator == nil {
+				errors = append(errors, fmt.Errorf("%w (invalid type for %s)", ErrPatternCollision, bPart))
+				continue
+			}
+
+			// fail if not valid
+			if _, valid := input.Validator(aPart); valid {
+				errors = append(errors, fmt.Errorf("%w (%s captures '%s')", ErrPatternCollision, bPart, aPart))
+				continue
+			}
+		}
+
+		errors = append(errors, nil)
+
+	}
+
+	// at least 1 URI part not matching -> no collision
+	var firstError error
+	for _, err := range errors {
+		if err != nil && firstError == nil {
+			firstError = err
+		}
+
+		if err == nil {
+			return nil
+		}
+	}
+
+	return firstError
+}
+
+// SplitURL without empty sets
+func SplitURL(url string) []string {
+	trimmed := strings.Trim(url, " /\t\r\n")
+	split := strings.Split(trimmed, "/")
+
+	// remove empty set when empty url
+	if len(split) == 1 && len(split[0]) == 0 {
+		return []string{}
+	}
+	return split
+}

internal/config/config_test.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
 func TestLegalServiceName(t *testing.T) {
@@ -80,7 +80,8 @@ func TestLegalServiceName(t *testing.T) {
 	for i, test := range tests {
 
 		t.Run(fmt.Sprintf("service.%d", i), func(t *testing.T) {
-			_, err := Parse(strings.NewReader(test.Raw))
+			srv := &Server{}
+			err := srv.Parse(strings.NewReader(test.Raw))
 
 			if err == nil && test.Error != nil {
 				t.Errorf("expected an error: '%s'", test.Error.Error())
@@ -134,7 +135,8 @@ func TestAvailableMethods(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("service.%d", i), func(t *testing.T) {
-			_, err := Parse(strings.NewReader(test.Raw))
+			srv := &Server{}
+			err := srv.Parse(strings.NewReader(test.Raw))
 
 			if test.ValidMethod && err != nil {
 				t.Errorf("unexpected error: '%s'", err.Error())
@@ -150,20 +152,22 @@ func TestAvailableMethods(t *testing.T) {
 }
 func TestParseEmpty(t *testing.T) {
 	t.Parallel()
-	reader := strings.NewReader(`[]`)
-	_, err := Parse(reader)
+	r := strings.NewReader(`[]`)
+	srv := &Server{}
+	err := srv.Parse(r)
 	if err != nil {
 		t.Errorf("unexpected error (got '%s')", err)
 		t.FailNow()
 	}
 }
 func TestParseJsonError(t *testing.T) {
-	reader := strings.NewReader(`{
+	r := strings.NewReader(`{
 		"GET": {
 			"info": "info
 		},
 	}`) // trailing ',' is invalid JSON
-	_, err := Parse(reader)
+	srv := &Server{}
+	err := srv.Parse(r)
 	if err == nil {
 		t.Errorf("expected error")
 		t.FailNow()
@@ -180,7 +184,7 @@ func TestParseMissingMethodDescription(t *testing.T) {
 			`[ { "method": "GET", "path": "/" }]`,
 			false,
 		},
-		{ // missing description
+		{ // missing descriptiontype
 			`[ { "method": "GET", "path": "/subservice" }]`,
 			false,
 		},
@@ -205,7 +209,8 @@ func TestParseMissingMethodDescription(t *testing.T) {
 	for i, test := range tests {
 
 		t.Run(fmt.Sprintf("method.%d", i), func(t *testing.T) {
-			_, err := Parse(strings.NewReader(test.Raw))
+			srv := &Server{}
+			err := srv.Parse(strings.NewReader(test.Raw))
 
 			if test.ValidDescription && err != nil {
 				t.Errorf("unexpected error: '%s'", err)
@@ -223,7 +228,7 @@ func TestParseMissingMethodDescription(t *testing.T) {
 
 func TestParamEmptyRenameNoRename(t *testing.T) {
 	t.Parallel()
-	reader := strings.NewReader(`[
+	r := strings.NewReader(`[
 		{
 			"method": "GET",
 			"path": "/",
@@ -233,7 +238,9 @@ func TestParamEmptyRenameNoRename(t *testing.T) {
 			}
 		}
 	]`)
-	srv, err := Parse(reader, builtin.AnyDataType{})
+	srv := &Server{}
+	srv.Validators = append(srv.Validators, validator.AnyType{})
+	err := srv.Parse(r)
 	if err != nil {
 		t.Errorf("unexpected error: '%s'", err)
 		t.FailNow()
@@ -254,7 +261,7 @@ func TestParamEmptyRenameNoRename(t *testing.T) {
 }
 func TestOptionalParam(t *testing.T) {
 	t.Parallel()
-	reader := strings.NewReader(`[
+	r := strings.NewReader(`[
 		{
 			"method": "GET",
 			"path": "/",
@@ -267,7 +274,10 @@ func TestOptionalParam(t *testing.T) {
 			}
 		}
 	]`)
-	srv, err := Parse(reader, builtin.AnyDataType{}, builtin.BoolDataType{})
+	srv := &Server{}
+	srv.Validators = append(srv.Validators, validator.AnyType{})
+	srv.Validators = append(srv.Validators, validator.BoolType{})
+	err := srv.Parse(r)
 	if err != nil {
 		t.Errorf("unexpected error: '%s'", err)
 		t.FailNow()
@@ -577,7 +587,9 @@ func TestParseParameters(t *testing.T) {
 	for i, test := range tests {
 
 		t.Run(fmt.Sprintf("method.%d", i), func(t *testing.T) {
-			_, err := Parse(strings.NewReader(test.Raw), builtin.AnyDataType{})
+			srv := &Server{}
+			srv.Validators = append(srv.Validators, validator.AnyType{})
+			err := srv.Parse(strings.NewReader(test.Raw))
 
 			if err == nil && test.Error != nil {
 				t.Errorf("expected an error: '%s'", test.Error.Error())
@@ -814,7 +826,10 @@ func TestServiceCollision(t *testing.T) {
 	for i, test := range tests {
 
 		t.Run(fmt.Sprintf("method.%d", i), func(t *testing.T) {
-			_, err := Parse(strings.NewReader(test.Config), builtin.StringDataType{}, builtin.UintDataType{})
+			srv := &Server{}
+			srv.Validators = append(srv.Validators, validator.StringType{})
+			srv.Validators = append(srv.Validators, validator.UintType{})
+			err := srv.Parse(strings.NewReader(test.Config))
 
 			if err == nil && test.Error != nil {
 				t.Errorf("expected an error: '%s'", test.Error.Error())
@@ -862,6 +877,36 @@ func TestMatchSimple(t *testing.T) {
 			"/a",
 			false,
 		},
+		{ // root url
+			`[ {
+					"method": "GET",
+					"path": "/a",
+					"info": "info",
+					"in": {}
+			} ]`,
+			"/",
+			false,
+		},
+		{
+			`[ {
+					"method": "GET",
+					"path": "/a",
+					"info": "info",
+					"in": {}
+			} ]`,
+			"/",
+			false,
+		},
+		{
+			`[ {
+					"method": "GET",
+					"path": "/",
+					"info": "info",
+					"in": {}
+			} ]`,
+			"/",
+			true,
+		},
 		{
 			`[ {
 					"method": "GET",
@@ -951,7 +996,11 @@ func TestMatchSimple(t *testing.T) {
 	for i, test := range tests {
 
 		t.Run(fmt.Sprintf("method.%d", i), func(t *testing.T) {
-			srv, err := Parse(strings.NewReader(test.Config), builtin.AnyDataType{}, builtin.IntDataType{}, builtin.BoolDataType{})
+			srv := &Server{}
+			srv.Validators = append(srv.Validators, validator.AnyType{})
+			srv.Validators = append(srv.Validators, validator.IntType{})
+			srv.Validators = append(srv.Validators, validator.BoolType{})
+			err := srv.Parse(strings.NewReader(test.Config))
 
 			if err != nil {
 				t.Errorf("unexpected error: '%s'", err)
@@ -978,3 +1027,80 @@ func TestMatchSimple(t *testing.T) {
 	}
 
 }
+
+func TestFindPriority(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		Config       string
+		URL          string
+		MatchingDesc string
+	}{
+		{
+			`[
+				{ "method": "GET", "path": "/a", "info": "s1" },
+				{ "method": "GET", "path": "/",  "info": "s2" }
+			]`,
+			"/",
+			"s2",
+		},
+		{
+			`[
+				{ "method": "GET", "path": "/",  "info": "s2" },
+				{ "method": "GET", "path": "/a", "info": "s1" }
+			]`,
+			"/",
+			"s2",
+		},
+		{
+			`[
+				{ "method": "GET", "path": "/a", "info": "s1" },
+				{ "method": "GET", "path": "/",  "info": "s2" }
+			]`,
+			"/a",
+			"s1",
+		},
+		{
+			`[
+				{ "method": "GET", "path": "/a/b/c",  "info": "s1" },
+				{ "method": "GET", "path": "/a/b",    "info": "s2" }
+			]`,
+			"/a/b/c",
+			"s1",
+		},
+		{
+			`[
+				{ "method": "GET", "path": "/a/b/c",  "info": "s1" },
+				{ "method": "GET", "path": "/a/b",    "info": "s2" }
+			]`,
+			"/a/b/",
+			"s2",
+		},
+	}
+
+	for i, test := range tests {
+
+		t.Run(fmt.Sprintf("method.%d", i), func(t *testing.T) {
+			srv := &Server{}
+			srv.Validators = append(srv.Validators, validator.AnyType{})
+			srv.Validators = append(srv.Validators, validator.IntType{})
+			srv.Validators = append(srv.Validators, validator.BoolType{})
+			err := srv.Parse(strings.NewReader(test.Config))
+
+			if err != nil {
+				t.Errorf("unexpected error: '%s'", err)
+				t.FailNow()
+			}
+
+			req := httptest.NewRequest(http.MethodGet, test.URL, nil)
+			service := srv.Find(req)
+			if service == nil {
+				t.Errorf("expected to find a service")
+				t.FailNow()
+			}
+			if service.Description != test.MatchingDesc {
+				t.Errorf("expected description '%s', got '%s'", test.MatchingDesc, service.Description)
+				t.FailNow()
+			}
+		})
+	}
+}

internal/config/errors.go

@@ -1,60 +1,61 @@
 package config
 
-// cerr allows you to create constant "const" error with type boxing.
-type cerr string
+// Err allows you to create constant "const" error with type boxing.
+type Err string
 
-// Error implements the error builtin interface.
-func (err cerr) Error() string {
+func (err Err) Error() string {
 	return string(err)
 }
 
-// ErrRead - a problem ocurred when trying to read the configuration file
-const ErrRead = cerr("cannot read config")
+const (
+	// ErrRead - read error
+	ErrRead = Err("cannot read config")
 
-// ErrUnknownMethod - invalid http method
-const ErrUnknownMethod = cerr("unknown HTTP method")
+	// ErrUnknownMethod - unknown http method
+	ErrUnknownMethod = Err("unknown HTTP method")
 
-// ErrFormat - a invalid format has been detected
-const ErrFormat = cerr("invalid config format")
+	// ErrFormat - invalid format
+	ErrFormat = Err("invalid config format")
 
-// ErrPatternCollision - there is a collision between 2 services' patterns (same method)
-const ErrPatternCollision = cerr("pattern collision")
+	// ErrPatternCollision - collision between 2 services' patterns
+	ErrPatternCollision = Err("pattern collision")
 
-// ErrInvalidPattern - a service pattern is malformed
-const ErrInvalidPattern = cerr("must begin with a '/' and not end with")
+	// ErrInvalidPattern - malformed service pattern
+	ErrInvalidPattern = Err("malformed service path: must begin with a '/' and not end with")
 
-// ErrInvalidPatternBraceCapture - a service pattern brace capture is invalid
-const ErrInvalidPatternBraceCapture = cerr("invalid uri capturing braces")
+	// ErrInvalidPatternBraceCapture - invalid brace capture
+	ErrInvalidPatternBraceCapture = Err("invalid uri parameter")
 
-// ErrUnspecifiedBraceCapture - a parameter brace capture is not specified in the pattern
-const ErrUnspecifiedBraceCapture = cerr("capturing brace missing in the path")
+	// ErrUnspecifiedBraceCapture - missing path brace capture
+	ErrUnspecifiedBraceCapture = Err("missing uri parameter")
 
-// ErrMandatoryRename - capture/query parameters must have a rename
-const ErrMandatoryRename = cerr("capture and query parameters must have a 'name'")
+	// ErrUndefinedBraceCapture - missing capturing brace definition
+	ErrUndefinedBraceCapture = Err("missing uri parameter definition")
 
-// ErrUndefinedBraceCapture - a parameter brace capture in the pattern is not defined in parameters
-const ErrUndefinedBraceCapture = cerr("capturing brace missing input definition")
+	// ErrMandatoryRename - capture/query parameters must be renamed
+	ErrMandatoryRename = Err("uri and query parameters must be renamed")
 
-// ErrMissingDescription - a service is missing its description
-const ErrMissingDescription = cerr("missing description")
+	// ErrMissingDescription - a service is missing its description
+	ErrMissingDescription = Err("missing description")
 
-// ErrIllegalOptionalURIParam - an URI parameter cannot be optional
-const ErrIllegalOptionalURIParam = cerr("URI parameter cannot be optional")
+	// ErrIllegalOptionalURIParam - uri parameter cannot optional
+	ErrIllegalOptionalURIParam = Err("uri parameter cannot be optional")
 
-// ErrOptionalOption - an output is optional
-const ErrOptionalOption = cerr("output cannot be optional")
+	// ErrOptionalOption - cannot have optional output
+	ErrOptionalOption = Err("output cannot be optional")
 
-// ErrMissingParamDesc - a parameter is missing its description
-const ErrMissingParamDesc = cerr("missing parameter description")
+	// ErrMissingParamDesc - missing parameter description
+	ErrMissingParamDesc = Err("missing parameter description")
 
-// ErrUnknownDataType - a parameter has an unknown datatype name
-const ErrUnknownDataType = cerr("unknown data type")
+	// ErrUnknownParamType - unknown parameter type
+	ErrUnknownParamType = Err("unknown parameter datatype")
 
-// ErrIllegalParamName - a parameter has an illegal name
-const ErrIllegalParamName = cerr("illegal parameter name")
+	// ErrIllegalParamName - illegal parameter name
+	ErrIllegalParamName = Err("illegal parameter name")
 
-// ErrMissingParamType - a parameter has an illegal type
-const ErrMissingParamType = cerr("missing parameter type")
+	// ErrMissingParamType - missing parameter type
+	ErrMissingParamType = Err("missing parameter type")
 
-// ErrParamNameConflict - a parameter has a conflict with its name/rename field
-const ErrParamNameConflict = cerr("name conflict for parameter")
+	// ErrParamNameConflict - name/rename conflict
+	ErrParamNameConflict = Err("parameter name conflict")
+)

internal/config/func.go

@@ -1,15 +0,0 @@
-package config
-
-import "strings"
-
-// SplitURL without empty sets
-func SplitURL(url string) []string {
-	trimmed := strings.Trim(url, " /\t\r\n")
-	split := strings.Split(trimmed, "/")
-
-	// remove empty set when empty url
-	if len(split) == 1 && len(split[0]) == 0 {
-		return []string{}
-	}
-	return split
-}

internal/config/parameter.go

@@ -1,38 +1,48 @@
 package config
 
 import (
-	"git.xdrm.io/go/aicra/datatype"
+	"reflect"
+
+	"github.com/xdrm-io/aicra/validator"
 )
 
-// Validate implements the validator interface
-func (param *Parameter) Validate(datatypes ...datatype.T) error {
-	// missing description
+// Parameter represents a parameter definition (from api.json)
+type Parameter struct {
+	Description string `json:"info"`
+	Type        string `json:"type"`
+	Rename      string `json:"name,omitempty"`
+	Optional    bool
+	// GoType is the type the Validator will cast into
+	GoType reflect.Type
+	// Validator is inferred from the "type" property
+	Validator validator.ValidateFunc
+}
+
+func (param *Parameter) validate(datatypes ...validator.Type) error {
 	if len(param.Description) < 1 {
 		return ErrMissingParamDesc
 	}
 
-	// invalid type
 	if len(param.Type) < 1 || param.Type == "?" {
 		return ErrMissingParamType
 	}
 
-	// optional type transform
+	// optional type
 	if param.Type[0] == '?' {
 		param.Optional = true
 		param.Type = param.Type[1:]
 	}
 
-	// assign the datatype
+	// find validator
 	for _, dtype := range datatypes {
-		param.Validator = dtype.Build(param.Type, datatypes...)
-		param.ExtractType = dtype.Type()
+		param.Validator = dtype.Validator(param.Type, datatypes...)
+		param.GoType = dtype.GoType()
 		if param.Validator != nil {
 			break
 		}
 	}
 	if param.Validator == nil {
-		return ErrUnknownDataType
+		return ErrUnknownParamType
 	}
-
 	return nil
 }

internal/config/server.go

@@ -1,169 +0,0 @@
-package config
-
-import (
-	"encoding/json"
-	"fmt"
-	"io"
-	"net/http"
-
-	"git.xdrm.io/go/aicra/datatype"
-)
-
-// Parse builds a server configuration from a json reader and checks for most format errors.
-// you can provide additional DataTypes as variadic arguments
-func Parse(r io.Reader, dtypes ...datatype.T) (*Server, error) {
-	server := &Server{
-		Types:    make([]datatype.T, 0),
-		Services: make([]*Service, 0),
-	}
-
-	// add data types
-	for _, dtype := range dtypes {
-		server.Types = append(server.Types, dtype)
-	}
-
-	if err := json.NewDecoder(r).Decode(&server.Services); err != nil {
-		return nil, fmt.Errorf("%s: %w", ErrRead, err)
-	}
-
-	if err := server.Validate(); err != nil {
-		return nil, fmt.Errorf("%s: %w", ErrFormat, err)
-	}
-
-	return server, nil
-}
-
-// Validate implements the validator interface
-func (server Server) Validate(datatypes ...datatype.T) error {
-	for _, service := range server.Services {
-		err := service.Validate(server.Types...)
-		if err != nil {
-			return fmt.Errorf("%s '%s': %w", service.Method, service.Pattern, err)
-		}
-	}
-
-	// check for collisions
-	if err := server.collide(); err != nil {
-		return fmt.Errorf("%s: %w", ErrFormat, err)
-	}
-
-	return nil
-}
-
-// Find a service matching an incoming HTTP request
-func (server Server) Find(r *http.Request) *Service {
-	for _, service := range server.Services {
-		if matches := service.Match(r); matches {
-			return service
-		}
-	}
-
-	return nil
-}
-
-// collide returns if there is collision between services
-func (server *Server) collide() error {
-	length := len(server.Services)
-
-	// for each service combination
-	for a := 0; a < length; a++ {
-		for b := a + 1; b < length; b++ {
-			aService := server.Services[a]
-			bService := server.Services[b]
-
-			// ignore different method
-			if aService.Method != bService.Method {
-				continue
-			}
-
-			aParts := SplitURL(aService.Pattern)
-			bParts := SplitURL(bService.Pattern)
-
-			// not same size
-			if len(aParts) != len(bParts) {
-				continue
-			}
-
-			partErrors := make([]error, 0)
-
-			// for each part
-			for pi, aPart := range aParts {
-				bPart := bParts[pi]
-
-				aIsCapture := len(aPart) > 1 && aPart[0] == '{'
-				bIsCapture := len(bPart) > 1 && bPart[0] == '{'
-
-				// both captures -> as we cannot check, consider a collision
-				if aIsCapture && bIsCapture {
-					partErrors = append(partErrors, fmt.Errorf("(%s '%s') vs (%s '%s'): %w (path %s and %s)", aService.Method, aService.Pattern, bService.Method, bService.Pattern, ErrPatternCollision, aPart, bPart))
-					continue
-				}
-
-				// no capture -> check equal
-				if !aIsCapture && !bIsCapture {
-					if aPart == bPart {
-						partErrors = append(partErrors, fmt.Errorf("(%s '%s') vs (%s '%s'): %w (same path '%s')", aService.Method, aService.Pattern, bService.Method, bService.Pattern, ErrPatternCollision, aPart))
-						continue
-					}
-				}
-
-				// A captures B -> check type (B is A ?)
-				if aIsCapture {
-					input, exists := aService.Input[aPart]
-
-					// fail if no type or no validator
-					if !exists || input.Validator == nil {
-						partErrors = append(partErrors, fmt.Errorf("(%s '%s') vs (%s '%s'): %w (invalid type for %s)", aService.Method, aService.Pattern, bService.Method, bService.Pattern, ErrPatternCollision, aPart))
-						continue
-					}
-
-					// fail if not valid
-					if _, valid := input.Validator(bPart); valid {
-						partErrors = append(partErrors, fmt.Errorf("(%s '%s') vs (%s '%s'): %w (%s captures '%s')", aService.Method, aService.Pattern, bService.Method, bService.Pattern, ErrPatternCollision, aPart, bPart))
-						continue
-					}
-
-					// B captures A -> check type (A is B ?)
-				} else if bIsCapture {
-					input, exists := bService.Input[bPart]
-
-					// fail if no type or no validator
-					if !exists || input.Validator == nil {
-						partErrors = append(partErrors, fmt.Errorf("(%s '%s') vs (%s '%s'): %w (invalid type for %s)", aService.Method, aService.Pattern, bService.Method, bService.Pattern, ErrPatternCollision, bPart))
-						continue
-					}
-
-					// fail if not valid
-					if _, valid := input.Validator(aPart); valid {
-						partErrors = append(partErrors, fmt.Errorf("(%s '%s') vs (%s '%s'): %w (%s captures '%s')", aService.Method, aService.Pattern, bService.Method, bService.Pattern, ErrPatternCollision, bPart, aPart))
-						continue
-					}
-				}
-
-				partErrors = append(partErrors, nil)
-
-			}
-
-			// if at least 1 url part does not match -> ok
-			var firstError error
-			oneMismatch := false
-			for _, err := range partErrors {
-				if err != nil && firstError == nil {
-					firstError = err
-				}
-
-				if err == nil {
-					oneMismatch = true
-					continue
-				}
-			}
-
-			if !oneMismatch {
-				return firstError
-			}
-
-		}
-	}
-
-	return nil
-}

internal/config/service.go

@@ -6,42 +6,71 @@ import (
 	"regexp"
 	"strings"
 
-	"git.xdrm.io/go/aicra/datatype"
+	"github.com/xdrm-io/aicra/validator"
 )
 
-var braceRegex = regexp.MustCompile(`^{([a-z_-]+)}$`)
-var queryRegex = regexp.MustCompile(`^GET@([a-z_-]+)$`)
+var (
+	captureRegex         = regexp.MustCompile(`^{([a-z_-]+)}$`)
+	queryRegex           = regexp.MustCompile(`^GET@([a-z_-]+)$`)
+	availableHTTPMethods = []string{http.MethodGet, http.MethodPost, http.MethodPut, http.MethodDelete}
+)
+
+// Service definition
+type Service struct {
+	Method      string                `json:"method"`
+	Pattern     string                `json:"path"`
+	Scope       [][]string            `json:"scope"`
+	Description string                `json:"info"`
+	Input       map[string]*Parameter `json:"in"`
+	Output      map[string]*Parameter `json:"out"`
+
+	// Captures contains references to URI parameters from the `Input` map. The format
+	// of these parameter names is "{paramName}"
+	Captures []*BraceCapture
+
+	// Query contains references to HTTP Query parameters from the `Input` map.
+	// Query parameters names are "GET@paramName", this map contains escaped names (e.g. "paramName")
+	Query map[string]*Parameter
+
+	// Form references form parameters from the `Input` map (all but Captures and Query).
+	Form map[string]*Parameter
+}
+
+// BraceCapture links to the related URI parameter
+type BraceCapture struct {
+	Name  string
+	Index int
+	Ref   *Parameter
+}
 
 // Match returns if this service would handle this HTTP request
 func (svc *Service) Match(req *http.Request) bool {
-	// method
-	if req.Method != svc.Method {
-		return false
+	var (
+		uri        = req.RequestURI
+		queryIndex = strings.IndexByte(uri, '?')
+	)
+
+	// remove query part for matching the pattern
+	if queryIndex > -1 {
+		uri = uri[:queryIndex]
 	}
 
-	// check path
-	if !svc.matchPattern(req.RequestURI) {
-		return false
-	}
-
-	// check and extract input
-	// todo: check if input match and extract models
-
-	return true
+	return req.Method == svc.Method && svc.matchPattern(uri)
 }
 
 // checks if an uri matches the service's pattern
 func (svc *Service) matchPattern(uri string) bool {
-	uriparts := SplitURL(uri)
-	parts := SplitURL(svc.Pattern)
+	var (
+		uriparts = SplitURL(uri)
+		parts    = SplitURL(svc.Pattern)
+	)
 
-	// fail if size differ
 	if len(uriparts) != len(parts) {
 		return false
 	}
 
 	// root url '/'
-	if len(parts) == 0 {
+	if len(parts) == 0 && len(uriparts) == 0 {
 		return true
 	}
 
@@ -76,40 +105,35 @@ func (svc *Service) matchPattern(uri string) bool {
 }
 
 // Validate implements the validator interface
-func (svc *Service) Validate(datatypes ...datatype.T) error {
-	// check method
-	err := svc.isMethodAvailable()
+func (svc *Service) validate(datatypes ...validator.Type) error {
+	err := svc.checkMethod()
 	if err != nil {
 		return fmt.Errorf("field 'method': %w", err)
 	}
 
-	// check pattern
 	svc.Pattern = strings.Trim(svc.Pattern, " \t\r\n")
-	err = svc.isPatternValid()
+	err = svc.checkPattern()
 	if err != nil {
 		return fmt.Errorf("field 'path': %w", err)
 	}
 
-	// check description
 	if len(strings.Trim(svc.Description, " \t\r\n")) < 1 {
 		return fmt.Errorf("field 'description': %w", ErrMissingDescription)
 	}
 
-	// check input parameters
-	err = svc.validateInput(datatypes)
+	err = svc.checkInput(datatypes)
 	if err != nil {
 		return fmt.Errorf("field 'in': %w", err)
 	}
 
-	// fail if a brace capture remains undefined
+	// fail when a brace capture remains undefined
 	for _, capture := range svc.Captures {
 		if capture.Ref == nil {
 			return fmt.Errorf("field 'in': %s: %w", capture.Name, ErrUndefinedBraceCapture)
 		}
 	}
 
-	// check output
-	err = svc.validateOutput(datatypes)
+	err = svc.checkOutput(datatypes)
 	if err != nil {
 		return fmt.Errorf("field 'out': %w", err)
 	}
@@ -117,7 +141,7 @@ func (svc *Service) Validate(datatypes ...datatype.T) error {
 	return nil
 }
 
-func (svc *Service) isMethodAvailable() error {
+func (svc *Service) checkMethod() error {
 	for _, available := range availableHTTPMethods {
 		if svc.Method == available {
 			return nil
@@ -126,7 +150,14 @@ func (svc *Service) isMethodAvailable() error {
 	return ErrUnknownMethod
 }
 
-func (svc *Service) isPatternValid() error {
+// checkPattern checks for the validity of the pattern definition (i.e. the uri)
+//
+// Note that the uri can contain capture params e.g. `/a/{b}/c/{d}`, in this
+// example, input parameters with names `{b}` and `{d}` are expected.
+//
+// This methods sets up the service state with adding capture params that are
+// expected; checkInputs() will be able to check params agains pattern captures.
+func (svc *Service) checkPattern() error {
 	length := len(svc.Pattern)
 
 	// empty pattern
@@ -149,7 +180,7 @@ func (svc *Service) isPatternValid() error {
 		}
 
 		// if brace capture
-		if matches := braceRegex.FindAllStringSubmatch(part, -1); len(matches) > 0 && len(matches[0]) > 1 {
+		if matches := captureRegex.FindAllStringSubmatch(part, -1); len(matches) > 0 && len(matches[0]) > 1 {
 			braceName := matches[0][1]
 
 			// append
@@ -168,147 +199,183 @@ func (svc *Service) isPatternValid() error {
 		if strings.ContainsAny(part, "{}") {
 			return ErrInvalidPatternBraceCapture
 		}
-
 	}
 
 	return nil
 }
 
-func (svc *Service) validateInput(types []datatype.T) error {
-
-	// ignore no parameter
+func (svc *Service) checkInput(types []validator.Type) error {
+	// no parameter
 	if svc.Input == nil || len(svc.Input) < 1 {
-		svc.Input = make(map[string]*Parameter, 0)
+		svc.Input = map[string]*Parameter{}
 		return nil
 	}
 
 	// for each parameter
-	for paramName, param := range svc.Input {
-		if len(paramName) < 1 {
-			return fmt.Errorf("%s: %w", paramName, ErrIllegalParamName)
+	for name, p := range svc.Input {
+		if len(name) < 1 {
+			return fmt.Errorf("%s: %w", name, ErrIllegalParamName)
 		}
 
-		// fail if brace capture does not exists in pattern
-		var iscapture, isquery bool
-		if matches := braceRegex.FindAllStringSubmatch(paramName, -1); len(matches) > 0 && len(matches[0]) > 1 {
-			braceName := matches[0][1]
-
-			found := false
-			for _, capture := range svc.Captures {
-				if capture.Name == braceName {
-					capture.Ref = param
-					found = true
-					break
-				}
-			}
-			if !found {
-				return fmt.Errorf("%s: %w", paramName, ErrUnspecifiedBraceCapture)
-			}
-			iscapture = true
-
-		} else if matches := queryRegex.FindAllStringSubmatch(paramName, -1); len(matches) > 0 && len(matches[0]) > 1 {
-
-			queryName := matches[0][1]
-
-			// init map
-			if svc.Query == nil {
-				svc.Query = make(map[string]*Parameter)
-			}
-			svc.Query[queryName] = param
-			isquery = true
-		} else {
-			if svc.Form == nil {
-				svc.Form = make(map[string]*Parameter)
-			}
-			svc.Form[paramName] = param
-		}
-
-		// fail if capture or query without rename
-		if len(param.Rename) < 1 && (iscapture || isquery) {
-			return fmt.Errorf("%s: %w", paramName, ErrMandatoryRename)
-		}
-
-		// use param name if no rename
-		if len(param.Rename) < 1 {
-			param.Rename = paramName
-		}
-
-		err := param.Validate(types...)
+		// parse parameters: capture (uri), query or form and update the service
+		// attributes accordingly
+		ptype, err := svc.parseParam(name, p)
 		if err != nil {
-			return fmt.Errorf("%s: %w", paramName, err)
+			return err
+		}
+
+		// Rename mandatory for capture and query
+		if len(p.Rename) < 1 && (ptype == captureParam || ptype == queryParam) {
+			return fmt.Errorf("%s: %w", name, ErrMandatoryRename)
+		}
+
+		// fallback to name when Rename is not provided
+		if len(p.Rename) < 1 {
+			p.Rename = name
+		}
+
+		err = p.validate(types...)
+		if err != nil {
+			return fmt.Errorf("%s: %w", name, err)
 		}
 
 		// capture parameter cannot be optional
-		if iscapture && param.Optional {
-			return fmt.Errorf("%s: %w", paramName, ErrIllegalOptionalURIParam)
+		if p.Optional && ptype == captureParam {
+			return fmt.Errorf("%s: %w", name, ErrIllegalOptionalURIParam)
 		}
 
-		// fail on name/rename conflict
-		for paramName2, param2 := range svc.Input {
-			// ignore self
-			if paramName == paramName2 {
-				continue
-			}
-
-			// 3.2.1. Same rename field
-			// 3.2.2. Not-renamed field matches a renamed field
-			// 3.2.3. Renamed field matches name
-			if param.Rename == param2.Rename || paramName == param2.Rename || paramName2 == param.Rename {
-				return fmt.Errorf("%s: %w", paramName, ErrParamNameConflict)
-			}
-
+		err = nameConflicts(name, p, svc.Input)
+		if err != nil {
+			return err
 		}
-
 	}
-
 	return nil
 }
 
-func (svc *Service) validateOutput(types []datatype.T) error {
-
-	// ignore no parameter
+func (svc *Service) checkOutput(types []validator.Type) error {
+	// no parameter
 	if svc.Output == nil || len(svc.Output) < 1 {
 		svc.Output = make(map[string]*Parameter, 0)
 		return nil
 	}
 
-	// for each parameter
-	for paramName, param := range svc.Output {
-		if len(paramName) < 1 {
-			return fmt.Errorf("%s: %w", paramName, ErrIllegalParamName)
+	for name, p := range svc.Output {
+		if len(name) < 1 {
+			return fmt.Errorf("%s: %w", name, ErrIllegalParamName)
 		}
 
-		// use param name if no rename
-		if len(param.Rename) < 1 {
-			param.Rename = paramName
+		// fallback to name when Rename is not provided
+		if len(p.Rename) < 1 {
+			p.Rename = name
 		}
 
-		err := param.Validate(types...)
+		err := p.validate(types...)
 		if err != nil {
-			return fmt.Errorf("%s: %w", paramName, err)
+			return fmt.Errorf("%s: %w", name, err)
 		}
 
-		if param.Optional {
-			return fmt.Errorf("%s: %w", paramName, ErrOptionalOption)
+		if p.Optional {
+			return fmt.Errorf("%s: %w", name, ErrOptionalOption)
 		}
 
-		// fail on name/rename conflict
-		for paramName2, param2 := range svc.Output {
-			// ignore self
-			if paramName == paramName2 {
-				continue
-			}
-
-			// 3.2.1. Same rename field
-			// 3.2.2. Not-renamed field matches a renamed field
-			// 3.2.3. Renamed field matches name
-			if param.Rename == param2.Rename || paramName == param2.Rename || paramName2 == param.Rename {
-				return fmt.Errorf("%s: %w", paramName, ErrParamNameConflict)
-			}
-
+		err = nameConflicts(name, p, svc.Output)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+type paramType int
+
+const (
+	captureParam paramType = iota
+	queryParam
+	formParam
+)
+
+// parseParam determines which param type it is from its name:
+// - `{paramName}` is an capture; it captures a segment of the uri defined in
+//    the pattern definition, e.g. `/some/path/with/{paramName}/somewhere`
+// - `GET@paramName` is an uri query that is received from the http query format
+//    in the uri, e.g. `http://domain.com/uri?paramName=paramValue&param2=value2`
+// - any other name that contains valid characters is considered a Form
+//   parameter; it is extracted from the http request's body as: json, multipart
+//   or using the x-www-form-urlencoded format.
+//
+// Special notes:
+// - capture params MUST be found in the pattern definition.
+// - capture params MUST NOT be optional as they are in the pattern anyways.
+// - capture and query params MUST be renamed because the `{param}` or
+//   `GET@param` name formats cannot be translated to a valid go exported name.
+//    c.f. the `dynfunc` package that creates a handler func() signature from
+//    the service definitions (i.e. input and output parameters).
+func (svc *Service) parseParam(name string, p *Parameter) (paramType, error) {
+	var (
+		captureMatches = captureRegex.FindAllStringSubmatch(name, -1)
+		isCapture      = len(captureMatches) > 0 && len(captureMatches[0]) > 1
+	)
+
+	// Parameter is a capture (uri/{param})
+	if isCapture {
+		captureName := captureMatches[0][1]
+
+		// fail if brace capture does not exists in pattern
+		found := false
+		for _, capture := range svc.Captures {
+			if capture.Name == captureName {
+				capture.Ref = p
+				found = true
+				break
+			}
+		}
+		if !found {
+			return captureParam, fmt.Errorf("%s: %w", name, ErrUnspecifiedBraceCapture)
+		}
+		return captureParam, nil
+	}
+
+	var (
+		queryMatches = queryRegex.FindAllStringSubmatch(name, -1)
+		isQuery      = len(queryMatches) > 0 && len(queryMatches[0]) > 1
+	)
+
+	// Parameter is a query (uri?param)
+	if isQuery {
+		queryName := queryMatches[0][1]
+
+		// init map
+		if svc.Query == nil {
+			svc.Query = make(map[string]*Parameter)
+		}
+		svc.Query[queryName] = p
+
+		return queryParam, nil
+	}
+
+	// Parameter is a form param
+	if svc.Form == nil {
+		svc.Form = make(map[string]*Parameter)
+	}
+	svc.Form[name] = p
+	return formParam, nil
+}
+
+// nameConflicts returns whether ar given parameter has its name or Rename field
+// in conflict with an existing parameter
+func nameConflicts(name string, param *Parameter, others map[string]*Parameter) error {
+	for otherName, other := range others {
+		// ignore self
+		if otherName == name {
+			continue
+		}
+
+		// 1. same rename field
+		// 2. original name matches a renamed field
+		// 3. renamed field matches an original name
+		if param.Rename == other.Rename || name == other.Rename || otherName == param.Rename {
+			return fmt.Errorf("%s: %w", otherName, ErrParamNameConflict)
 		}
-
 	}
-
 	return nil
 }

internal/config/types.go

@@ -1,63 +0,0 @@
-package config
-
-import (
-	"net/http"
-	"reflect"
-
-	"git.xdrm.io/go/aicra/datatype"
-)
-
-var availableHTTPMethods = []string{http.MethodGet, http.MethodPost, http.MethodPut, http.MethodDelete}
-
-// validator unifies the check and format routine
-type validator interface {
-	Validate(...datatype.T) error
-}
-
-// Server represents a full server configuration
-type Server struct {
-	Types    []datatype.T
-	Services []*Service
-}
-
-// Service represents a service definition (from api.json)
-type Service struct {
-	Method      string                `json:"method"`
-	Pattern     string                `json:"path"`
-	Scope       [][]string            `json:"scope"`
-	Description string                `json:"info"`
-	Input       map[string]*Parameter `json:"in"`
-	Output      map[string]*Parameter `json:"out"`
-
-	// references to url parameters
-	// format: '/uri/{param}'
-	Captures []*BraceCapture
-
-	// references to Query parameters
-	// format: 'GET@paranName'
-	Query map[string]*Parameter
-
-	// references for form parameters (all but Captures and Query)
-	Form map[string]*Parameter
-}
-
-// Parameter represents a parameter definition (from api.json)
-type Parameter struct {
-	Description string `json:"info"`
-	Type        string `json:"type"`
-	Rename      string `json:"name,omitempty"`
-	// ExtractType is the type of data the datatype returns
-	ExtractType reflect.Type
-	// Optional is set to true when the type is prefixed with '?'
-	Optional bool
-
-	// Validator is inferred from @Type
-	Validator datatype.Validator
-}
-
-// BraceCapture links to the related URI parameter
-type BraceCapture struct {
-	Name  string
-	Index int
-	Ref   *Parameter
-}

internal/ctx/ctx.go

@@ -0,0 +1,13 @@
+package ctx
+
+// Key defines a custom context key type
+type Key int
+
+const (
+	// Request is the key for the current *http.Request
+	Request Key = iota
+	// Response is the key for the associated http.ResponseWriter
+	Response
+	// Auth is the key for the request's authentication information
+	Auth
+)

internal/dynfunc/errors.go

@@ -0,0 +1,52 @@
+package dynfunc
+
+// Err allows you to create constant "const" error with type boxing.
+type Err string
+
+func (err Err) Error() string {
+	return string(err)
+}
+
+const (
+	// ErrHandlerNotFunc - handler is not a func
+	ErrHandlerNotFunc = Err("handler must be a func")
+
+	// ErrNoServiceForHandler - no service matching this handler
+	ErrNoServiceForHandler = Err("no service found for this handler")
+
+	// errMissingHandlerArgumentParam - missing params arguments for handler
+	ErrMissingHandlerContextArgument = Err("missing handler first argument of type context.Context")
+
+	// ErrInvalidHandlerContextArgument - missing handler output error
+	ErrInvalidHandlerContextArgument = Err("first input argument should be of type context.Context")
+
+	// ErrMissingHandlerInputArgument - missing params arguments for handler
+	ErrMissingHandlerInputArgument = Err("missing handler argument: input struct")
+
+	// ErrUnexpectedInput - input argument is not expected
+	ErrUnexpectedInput = Err("unexpected input struct")
+
+	// ErrMissingHandlerOutputArgument - missing output for handler
+	ErrMissingHandlerOutputArgument = Err("missing handler first output argument: output struct")
+
+	// ErrMissingHandlerErrorArgument - missing error output for handler
+	ErrMissingHandlerErrorArgument = Err("missing handler last output argument of type api.Err")
+
+	// ErrInvalidHandlerErrorArgument - missing handler output error
+	ErrInvalidHandlerErrorArgument = Err("last output must be of type api.Err")
+
+	// ErrMissingParamArgument - missing parameters argument for handler
+	ErrMissingParamArgument = Err("handler second argument must be a struct")
+
+	// ErrUnexportedName - argument is unexported in struct
+	ErrUnexportedName = Err("unexported name")
+
+	// ErrWrongOutputArgumentType - wrong type for output first argument
+	ErrWrongOutputArgumentType = Err("handler first output argument must be a *struct")
+
+	// ErrMissingConfigArgument - missing an input/output argument in handler struct
+	ErrMissingConfigArgument = Err("missing an argument from the configuration")
+
+	// ErrWrongParamTypeFromConfig - a configuration parameter type is invalid in the handler param struct
+	ErrWrongParamTypeFromConfig = Err("invalid struct field type")
+)

internal/dynfunc/handler.go

@@ -0,0 +1,144 @@
+package dynfunc
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"reflect"
+
+	"github.com/xdrm-io/aicra/api"
+	"github.com/xdrm-io/aicra/internal/config"
+)
+
+// Handler represents a dynamic aicra service handler
+type Handler struct {
+	// signature defined from the service configuration
+	signature *Signature
+	// fn provided function that will be the service's handler
+	fn interface{}
+}
+
+// Build a handler from a dynamic function and checks its signature against a
+// service configuration
+//
+// `fn` must have as a signature : `func(context.Context, in) (*out, api.Err)`
+//  - `in` is a struct{} containing a field for each service input (with valid reflect.Type)
+//  - `out` is a struct{} containing a field for each service output (with valid reflect.Type)
+//
+// Special cases:
+//  - it there is no input,  `in` MUST be omitted
+//  - it there is no output, `out` CAN be omitted
+func Build(fn interface{}, service config.Service) (*Handler, error) {
+	var (
+		h = &Handler{
+			signature: BuildSignature(service),
+			fn:        fn,
+		}
+		fnType = reflect.TypeOf(fn)
+	)
+
+	if fnType.Kind() != reflect.Func {
+		return nil, ErrHandlerNotFunc
+	}
+	if err := h.signature.ValidateInput(fnType); err != nil {
+		return nil, fmt.Errorf("input: %w", err)
+	}
+	if err := h.signature.ValidateOutput(fnType); err != nil {
+		return nil, fmt.Errorf("output: %w", err)
+	}
+
+	return h, nil
+}
+
+// Handle binds input `data` into the dynamic function and returns an output map
+func (h *Handler) Handle(ctx context.Context, data map[string]interface{}) (map[string]interface{}, api.Err) {
+	var (
+		ert      = reflect.TypeOf(api.Err{})
+		fnv      = reflect.ValueOf(h.fn)
+		callArgs = make([]reflect.Value, 0)
+	)
+
+	// bind context
+	callArgs = append(callArgs, reflect.ValueOf(ctx))
+
+	inputStructRequired := fnv.Type().NumIn() > 1
+
+	// bind input arguments
+	if inputStructRequired {
+		// create zero value struct
+		var (
+			callStructPtr = reflect.New(fnv.Type().In(1))
+			callStruct    = callStructPtr.Elem()
+		)
+
+		// set each field
+		for name := range h.signature.Input {
+			field := callStruct.FieldByName(name)
+			if !field.CanSet() {
+				continue
+			}
+
+			// get value from @data
+			value, provided := data[name]
+			if !provided {
+				continue
+			}
+
+			var refvalue = reflect.ValueOf(value)
+
+			// T to pointer of T
+			if field.Kind() == reflect.Ptr {
+				var ptrType = field.Type().Elem()
+
+				if !refvalue.Type().ConvertibleTo(ptrType) {
+					log.Printf("Cannot convert %v into *%v", refvalue.Type(), ptrType)
+					return nil, api.ErrUncallableService
+				}
+
+				ptr := reflect.New(ptrType)
+				ptr.Elem().Set(reflect.ValueOf(value).Convert(ptrType))
+
+				field.Set(ptr)
+				continue
+			}
+
+			if !reflect.ValueOf(value).Type().ConvertibleTo(field.Type()) {
+				log.Printf("Cannot convert %v into %v", reflect.ValueOf(value).Type(), field.Type())
+				return nil, api.ErrUncallableService
+			}
+
+			field.Set(refvalue.Convert(field.Type()))
+		}
+		callArgs = append(callArgs, callStruct)
+	}
+
+	// call the handler
+	output := fnv.Call(callArgs)
+
+	// no output OR pointer to output struct is nil
+	outdata := make(map[string]interface{})
+	if len(h.signature.Output) < 1 || output[0].IsNil() {
+		var structerr = output[len(output)-1].Convert(ert)
+		return outdata, api.Err{
+			Code:   int(structerr.FieldByName("Code").Int()),
+			Reason: structerr.FieldByName("Reason").String(),
+			Status: int(structerr.FieldByName("Status").Int()),
+		}
+	}
+
+	// extract struct from pointer
+	returnStruct := output[0].Elem()
+
+	for name := range h.signature.Output {
+		field := returnStruct.FieldByName(name)
+		outdata[name] = field.Interface()
+	}
+
+	// extract api.Err
+	var structerr = output[len(output)-1].Convert(ert)
+	return outdata, api.Err{
+		Code:   int(structerr.FieldByName("Code").Int()),
+		Reason: structerr.FieldByName("Reason").String(),
+		Status: int(structerr.FieldByName("Status").Int()),
+	}
+}

internal/dynfunc/handler_test.go

@@ -0,0 +1,167 @@
+package dynfunc
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/xdrm-io/aicra/api"
+)
+
+type testsignature Signature
+
+// builds a mock service with provided arguments as Input and matched as Output
+func (s *testsignature) withArgs(dtypes ...reflect.Type) *testsignature {
+	if s.Input == nil {
+		s.Input = make(map[string]reflect.Type)
+	}
+	if s.Output == nil {
+		s.Output = make(map[string]reflect.Type)
+	}
+
+	for i, dtype := range dtypes {
+		name := fmt.Sprintf("P%d", i+1)
+		s.Input[name] = dtype
+		if dtype.Kind() == reflect.Ptr {
+			s.Output[name] = dtype.Elem()
+		} else {
+			s.Output[name] = dtype
+		}
+	}
+	return s
+}
+
+func TestInput(t *testing.T) {
+
+	type intstruct struct {
+		P1 int
+	}
+	type intptrstruct struct {
+		P1 *int
+	}
+
+	tcases := []struct {
+		Name           string
+		Spec           *testsignature
+		HasContext     bool
+		Fn             interface{}
+		Input          []interface{}
+		ExpectedOutput []interface{}
+		ExpectedErr    api.Err
+	}{
+		{
+			Name:           "none required none provided",
+			Spec:           (&testsignature{}).withArgs(),
+			Fn:             func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			HasContext:     false,
+			Input:          []interface{}{},
+			ExpectedOutput: []interface{}{},
+			ExpectedErr:    api.ErrSuccess,
+		},
+		{
+			Name: "int proxy (0)",
+			Spec: (&testsignature{}).withArgs(reflect.TypeOf(int(0))),
+			Fn: func(ctx context.Context, in intstruct) (*intstruct, api.Err) {
+				return &intstruct{P1: in.P1}, api.ErrSuccess
+			},
+			HasContext:     false,
+			Input:          []interface{}{int(0)},
+			ExpectedOutput: []interface{}{int(0)},
+			ExpectedErr:    api.ErrSuccess,
+		},
+		{
+			Name: "int proxy (11)",
+			Spec: (&testsignature{}).withArgs(reflect.TypeOf(int(0))),
+			Fn: func(ctx context.Context, in intstruct) (*intstruct, api.Err) {
+				return &intstruct{P1: in.P1}, api.ErrSuccess
+			},
+			HasContext:     false,
+			Input:          []interface{}{int(11)},
+			ExpectedOutput: []interface{}{int(11)},
+			ExpectedErr:    api.ErrSuccess,
+		},
+		{
+			Name: "*int proxy (nil)",
+			Spec: (&testsignature{}).withArgs(reflect.TypeOf(new(int))),
+			Fn: func(ctx context.Context, in intptrstruct) (*intptrstruct, api.Err) {
+				return &intptrstruct{P1: in.P1}, api.ErrSuccess
+			},
+			HasContext:     false,
+			Input:          []interface{}{},
+			ExpectedOutput: []interface{}{nil},
+			ExpectedErr:    api.ErrSuccess,
+		},
+		{
+			Name: "*int proxy (28)",
+			Spec: (&testsignature{}).withArgs(reflect.TypeOf(new(int))),
+			Fn: func(ctx context.Context, in intptrstruct) (*intstruct, api.Err) {
+				return &intstruct{P1: *in.P1}, api.ErrSuccess
+			},
+			HasContext:     false,
+			Input:          []interface{}{28},
+			ExpectedOutput: []interface{}{28},
+			ExpectedErr:    api.ErrSuccess,
+		},
+		{
+			Name: "*int proxy (13)",
+			Spec: (&testsignature{}).withArgs(reflect.TypeOf(new(int))),
+			Fn: func(ctx context.Context, in intptrstruct) (*intstruct, api.Err) {
+				return &intstruct{P1: *in.P1}, api.ErrSuccess
+			},
+			HasContext:     false,
+			Input:          []interface{}{13},
+			ExpectedOutput: []interface{}{13},
+			ExpectedErr:    api.ErrSuccess,
+		},
+	}
+
+	for _, tcase := range tcases {
+		t.Run(tcase.Name, func(t *testing.T) {
+			t.Parallel()
+
+			var handler = &Handler{
+				signature: &Signature{Input: tcase.Spec.Input, Output: tcase.Spec.Output},
+				fn:        tcase.Fn,
+			}
+
+			// build input
+			input := make(map[string]interface{})
+			for i, val := range tcase.Input {
+				var key = fmt.Sprintf("P%d", i+1)
+				input[key] = val
+			}
+
+			var output, err = handler.Handle(context.Background(), input)
+			if err != tcase.ExpectedErr {
+				t.Fatalf("expected api error <%v> got <%v>", tcase.ExpectedErr, err)
+			}
+
+			// check output
+			for i, expected := range tcase.ExpectedOutput {
+				var (
+					key         = fmt.Sprintf("P%d", i+1)
+					val, exists = output[key]
+				)
+				if !exists {
+					t.Fatalf("missing output[%s]", key)
+				}
+				if expected != val {
+					var (
+						expectedt   = reflect.ValueOf(expected)
+						valt        = reflect.ValueOf(val)
+						expectedNil = !expectedt.IsValid() || expectedt.Kind() == reflect.Ptr && expectedt.IsNil()
+						valNil      = !valt.IsValid() || valt.Kind() == reflect.Ptr && valt.IsNil()
+					)
+					// ignore both nil
+					if valNil && expectedNil {
+						continue
+					}
+					t.Fatalf("expected output[%s] to equal %T <%v> got %T <%v>", key, expected, expected, val, val)
+				}
+			}
+
+		})
+	}
+
+}

internal/dynfunc/signature.go

@@ -0,0 +1,159 @@
+package dynfunc
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/xdrm-io/aicra/api"
+	"github.com/xdrm-io/aicra/internal/config"
+)
+
+// Signature represents input/output arguments for service from the aicra configuration
+type Signature struct {
+	// Input arguments of the service
+	Input map[string]reflect.Type
+	// Output arguments of the service
+	Output map[string]reflect.Type
+}
+
+// BuildSignature builds a signature for a service configuration
+func BuildSignature(service config.Service) *Signature {
+	s := &Signature{
+		Input:  make(map[string]reflect.Type),
+		Output: make(map[string]reflect.Type),
+	}
+
+	for _, param := range service.Input {
+		if len(param.Rename) < 1 {
+			continue
+		}
+		// make a pointer if optional
+		if param.Optional {
+			s.Input[param.Rename] = reflect.PtrTo(param.GoType)
+			continue
+		}
+		s.Input[param.Rename] = param.GoType
+	}
+
+	for _, param := range service.Output {
+		if len(param.Rename) < 1 {
+			continue
+		}
+		s.Output[param.Rename] = param.GoType
+	}
+
+	return s
+}
+
+// ValidateInput validates a handler's input arguments against the service signature
+func (s *Signature) ValidateInput(handlerType reflect.Type) error {
+	ctxType := reflect.TypeOf((*context.Context)(nil)).Elem()
+
+	// missing or invalid first arg: context.Context
+	if handlerType.NumIn() < 1 {
+		return ErrMissingHandlerContextArgument
+	}
+	firstArgType := handlerType.In(0)
+
+	if !firstArgType.Implements(ctxType) {
+		return ErrInvalidHandlerContextArgument
+	}
+
+	// no input required
+	if len(s.Input) == 0 {
+		// input struct provided
+		if handlerType.NumIn() > 1 {
+			return ErrUnexpectedInput
+		}
+		return nil
+	}
+
+	// too much arguments
+	if handlerType.NumIn() != 2 {
+		return ErrMissingHandlerInputArgument
+	}
+
+	// arg must be a struct
+	inStruct := handlerType.In(1)
+	if inStruct.Kind() != reflect.Struct {
+		return ErrMissingParamArgument
+	}
+
+	// check for invalid param
+	for name, ptype := range s.Input {
+		if name[0] == strings.ToLower(name)[0] {
+			return fmt.Errorf("%s: %w", name, ErrUnexportedName)
+		}
+
+		field, exists := inStruct.FieldByName(name)
+		if !exists {
+			return fmt.Errorf("%s: %w", name, ErrMissingConfigArgument)
+		}
+
+		if !ptype.AssignableTo(field.Type) {
+			return fmt.Errorf("%s: %w (%s instead of %s)", name, ErrWrongParamTypeFromConfig, field.Type, ptype)
+		}
+	}
+
+	return nil
+}
+
+// ValidateOutput validates a handler's output arguments against the service signature
+func (s Signature) ValidateOutput(handlerType reflect.Type) error {
+	errType := reflect.TypeOf(api.ErrUnknown)
+
+	if handlerType.NumOut() < 1 {
+		return ErrMissingHandlerErrorArgument
+	}
+
+	// last output must be api.Err
+	lastArgType := handlerType.Out(handlerType.NumOut() - 1)
+	if !lastArgType.AssignableTo(errType) {
+		return ErrInvalidHandlerErrorArgument
+	}
+
+	// no output required -> ok
+	if len(s.Output) == 0 {
+		return nil
+	}
+
+	if handlerType.NumOut() < 2 {
+		return ErrMissingHandlerOutputArgument
+	}
+
+	// fail if first output is not a pointer to struct
+	outStructPtr := handlerType.Out(0)
+	if outStructPtr.Kind() != reflect.Ptr {
+		return ErrWrongOutputArgumentType
+	}
+
+	outStruct := outStructPtr.Elem()
+	if outStruct.Kind() != reflect.Struct {
+		return ErrWrongOutputArgumentType
+	}
+
+	// fail on invalid output
+	for name, ptype := range s.Output {
+		if name[0] == strings.ToLower(name)[0] {
+			return fmt.Errorf("%s: %w", name, ErrUnexportedName)
+		}
+
+		field, exists := outStruct.FieldByName(name)
+		if !exists {
+			return fmt.Errorf("%s: %w", name, ErrMissingConfigArgument)
+		}
+
+		// ignore types evalutating to nil
+		if ptype == nil {
+			continue
+		}
+
+		if !field.Type.ConvertibleTo(ptype) {
+			return fmt.Errorf("%s: %w (%s instead of %s)", name, ErrWrongParamTypeFromConfig, field.Type, ptype)
+		}
+	}
+
+	return nil
+}

internal/dynfunc/signature_test.go

@@ -0,0 +1,570 @@
+package dynfunc
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/xdrm-io/aicra/api"
+	"github.com/xdrm-io/aicra/internal/config"
+)
+
+func TestInputValidation(t *testing.T) {
+	tt := []struct {
+		name  string
+		input map[string]reflect.Type
+		fn    interface{}
+		err   error
+	}{
+		{
+			name:  "missing context",
+			input: map[string]reflect.Type{},
+			fn:    func() {},
+			err:   ErrMissingHandlerContextArgument,
+		},
+		{
+			name:  "invalid context",
+			input: map[string]reflect.Type{},
+			fn:    func(int) {},
+			err:   ErrInvalidHandlerContextArgument,
+		},
+		{
+			name:  "no input 0 given",
+			input: map[string]reflect.Type{},
+			fn:    func(context.Context) {},
+			err:   nil,
+		},
+		{
+			name:  "no input 1 given",
+			input: map[string]reflect.Type{},
+			fn:    func(context.Context, int) {},
+			err:   ErrUnexpectedInput,
+		},
+		{
+			name:  "no input 2 given",
+			input: map[string]reflect.Type{},
+			fn:    func(context.Context, int, string) {},
+			err:   ErrUnexpectedInput,
+		},
+		{
+			name: "1 input 0 given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func(context.Context) {},
+			err: ErrMissingHandlerInputArgument,
+		},
+		{
+			name: "1 input non-struct given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func(context.Context, int) {},
+			err: ErrMissingParamArgument,
+		},
+		{
+			name: "unexported input",
+			input: map[string]reflect.Type{
+				"test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func(context.Context, struct{}) {},
+			err: ErrUnexportedName,
+		},
+		{
+			name: "1 input empty struct given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func(context.Context, struct{}) {},
+			err: ErrMissingConfigArgument,
+		},
+		{
+			name: "1 input invalid given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func(context.Context, struct{ Test1 string }) {},
+			err: ErrWrongParamTypeFromConfig,
+		},
+		{
+			name: "1 input valid given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func(context.Context, struct{ Test1 int }) {},
+			err: nil,
+		},
+		{
+			name: "1 input ptr empty struct given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(int)),
+			},
+			fn:  func(context.Context, struct{}) {},
+			err: ErrMissingConfigArgument,
+		},
+		{
+			name: "1 input ptr invalid given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(int)),
+			},
+			fn:  func(context.Context, struct{ Test1 string }) {},
+			err: ErrWrongParamTypeFromConfig,
+		},
+		{
+			name: "1 input ptr invalid ptr type given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(int)),
+			},
+			fn:  func(context.Context, struct{ Test1 *string }) {},
+			err: ErrWrongParamTypeFromConfig,
+		},
+		{
+			name: "1 input ptr valid given",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(int)),
+			},
+			fn:  func(context.Context, struct{ Test1 *int }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid string",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(string("")),
+			},
+			fn:  func(context.Context, struct{ Test1 string }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid uint",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(uint(0)),
+			},
+			fn:  func(context.Context, struct{ Test1 uint }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid float64",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(float64(0)),
+			},
+			fn:  func(context.Context, struct{ Test1 float64 }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid []byte",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf([]byte("")),
+			},
+			fn:  func(context.Context, struct{ Test1 []byte }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid []rune",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf([]rune("")),
+			},
+			fn:  func(context.Context, struct{ Test1 []rune }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid *string",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(string)),
+			},
+			fn:  func(context.Context, struct{ Test1 *string }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid *uint",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(uint)),
+			},
+			fn:  func(context.Context, struct{ Test1 *uint }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid *float64",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new(float64)),
+			},
+			fn:  func(context.Context, struct{ Test1 *float64 }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid *[]byte",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new([]byte)),
+			},
+			fn:  func(context.Context, struct{ Test1 *[]byte }) {},
+			err: nil,
+		},
+		{
+			name: "1 valid *[]rune",
+			input: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(new([]rune)),
+			},
+			fn:  func(context.Context, struct{ Test1 *[]rune }) {},
+			err: nil,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			// mock spec
+			s := Signature{
+				Input:  tc.input,
+				Output: nil,
+			}
+
+			err := s.ValidateInput(reflect.TypeOf(tc.fn))
+			if err == nil && tc.err != nil {
+				t.Fatalf("expected an error: '%s'", tc.err.Error())
+			}
+			if err != nil && tc.err == nil {
+				t.Fatalf("unexpected error: '%s'", err.Error())
+			}
+
+			if err != nil && tc.err != nil {
+				if !errors.Is(err, tc.err) {
+					t.Fatalf("expected the error <%s> got <%s>", tc.err, err)
+				}
+			}
+		})
+	}
+}
+
+func TestOutputValidation(t *testing.T) {
+	tt := []struct {
+		name   string
+		output map[string]reflect.Type
+		fn     interface{}
+		err    error
+	}{
+		{
+			name:   "no output missing err",
+			output: map[string]reflect.Type{},
+			fn:     func() {},
+			err:    ErrMissingHandlerErrorArgument,
+		},
+		{
+			name:   "no output invalid err",
+			output: map[string]reflect.Type{},
+			fn:     func() bool { return true },
+			err:    ErrInvalidHandlerErrorArgument,
+		},
+		{
+			name:   "1 output none required",
+			output: map[string]reflect.Type{},
+			fn:     func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			err:    nil,
+		},
+		{
+			name: "no output 1 required",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() api.Err { return api.ErrSuccess },
+			err: ErrMissingHandlerOutputArgument,
+		},
+		{
+			name: "invalid int output",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (int, api.Err) { return 0, api.ErrSuccess },
+			err: ErrWrongOutputArgumentType,
+		},
+		{
+			name: "invalid int ptr output",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (*int, api.Err) { return nil, api.ErrSuccess },
+			err: ErrWrongOutputArgumentType,
+		},
+		{
+			name: "invalid struct output",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (struct{ Test1 int }, api.Err) { return struct{ Test1 int }{Test1: 1}, api.ErrSuccess },
+			err: ErrWrongOutputArgumentType,
+		},
+		{
+			name: "unexported param",
+			output: map[string]reflect.Type{
+				"test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			err: ErrUnexportedName,
+		},
+		{
+			name: "missing output param",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			err: ErrMissingConfigArgument,
+		},
+		{
+			name: "invalid output param",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (*struct{ Test1 string }, api.Err) { return nil, api.ErrSuccess },
+			err: ErrWrongParamTypeFromConfig,
+		},
+		{
+			name: "valid param",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+			},
+			fn:  func() (*struct{ Test1 int }, api.Err) { return nil, api.ErrSuccess },
+			err: nil,
+		},
+		{
+			name: "2 valid params",
+			output: map[string]reflect.Type{
+				"Test1": reflect.TypeOf(int(0)),
+				"Test2": reflect.TypeOf(string("")),
+			},
+			fn: func() (*struct {
+				Test1 int
+				Test2 string
+			}, api.Err) {
+				return nil, api.ErrSuccess
+			},
+			err: nil,
+		},
+		{
+			name: "nil type ignore typecheck",
+			output: map[string]reflect.Type{
+				"Test1": nil,
+			},
+			fn:  func() (*struct{ Test1 int }, api.Err) { return nil, api.ErrSuccess },
+			err: nil,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			// mock spec
+			s := Signature{
+				Input:  nil,
+				Output: tc.output,
+			}
+
+			err := s.ValidateOutput(reflect.TypeOf(tc.fn))
+			if !errors.Is(err, tc.err) {
+				t.Fatalf("expected the error <%s> got <%s>", tc.err, err)
+			}
+		})
+	}
+}
+
+func TestServiceValidation(t *testing.T) {
+
+	tt := []struct {
+		name string
+		in   []*config.Parameter
+		out  []*config.Parameter
+		fn   interface{}
+		err  error
+	}{
+		{
+			name: "missing context",
+			fn:   func() {},
+			err:  ErrMissingHandlerContextArgument,
+		},
+		{
+			name: "invalid context",
+			fn:   func(int) {},
+			err:  ErrInvalidHandlerContextArgument,
+		},
+		{
+			name: "missing error",
+			fn:   func(context.Context) {},
+			err:  ErrMissingHandlerErrorArgument,
+		},
+		{
+			name: "invalid error",
+			fn:   func(context.Context) int { return 1 },
+			err:  ErrInvalidHandlerErrorArgument,
+		},
+		{
+			name: "no in no out",
+			fn:   func(context.Context) api.Err { return api.ErrSuccess },
+			err:  nil,
+		},
+		{
+			name: "unamed in",
+			in: []*config.Parameter{
+				{
+					Rename: "", // should be ignored
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) api.Err { return api.ErrSuccess },
+			err: nil,
+		},
+		{
+			name: "missing in",
+			in: []*config.Parameter{
+				{
+					Rename: "Test1",
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) api.Err { return api.ErrSuccess },
+			err: ErrMissingHandlerInputArgument,
+		},
+		{
+			name: "valid in",
+			in: []*config.Parameter{
+				{
+					Rename: "Test1",
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context, struct{ Test1 int }) api.Err { return api.ErrSuccess },
+			err: nil,
+		},
+		{
+			name: "optional in not ptr",
+			in: []*config.Parameter{
+				{
+					Rename:   "Test1",
+					GoType:   reflect.TypeOf(int(0)),
+					Optional: true,
+				},
+			},
+			fn:  func(context.Context, struct{ Test1 int }) api.Err { return api.ErrSuccess },
+			err: ErrWrongParamTypeFromConfig,
+		},
+		{
+			name: "valid optional in",
+			in: []*config.Parameter{
+				{
+					Rename:   "Test1",
+					GoType:   reflect.TypeOf(int(0)),
+					Optional: true,
+				},
+			},
+			fn:  func(context.Context, struct{ Test1 *int }) api.Err { return api.ErrSuccess },
+			err: nil,
+		},
+
+		{
+			name: "unamed out",
+			out: []*config.Parameter{
+				{
+					Rename: "", // should be ignored
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) api.Err { return api.ErrSuccess },
+			err: nil,
+		},
+		{
+			name: "missing out struct",
+			out: []*config.Parameter{
+				{
+					Rename: "Test1",
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) api.Err { return api.ErrSuccess },
+			err: ErrMissingHandlerOutputArgument,
+		},
+		{
+			name: "invalid out struct type",
+			out: []*config.Parameter{
+				{
+					Rename: "Test1",
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) (int, api.Err) { return 0, api.ErrSuccess },
+			err: ErrWrongOutputArgumentType,
+		},
+		{
+			name: "missing out",
+			out: []*config.Parameter{
+				{
+					Rename: "Test1",
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) (*struct{}, api.Err) { return nil, api.ErrSuccess },
+			err: ErrMissingConfigArgument,
+		},
+		{
+			name: "valid out",
+			out: []*config.Parameter{
+				{
+					Rename: "Test1",
+					GoType: reflect.TypeOf(int(0)),
+				},
+			},
+			fn:  func(context.Context) (*struct{ Test1 int }, api.Err) { return nil, api.ErrSuccess },
+			err: nil,
+		},
+		{
+			name: "optional out not ptr",
+			out: []*config.Parameter{
+				{
+					Rename:   "Test1",
+					GoType:   reflect.TypeOf(int(0)),
+					Optional: true,
+				},
+			},
+			fn:  func(context.Context) (*struct{ Test1 *int }, api.Err) { return nil, api.ErrSuccess },
+			err: ErrWrongParamTypeFromConfig,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			service := config.Service{
+				Input:  make(map[string]*config.Parameter),
+				Output: make(map[string]*config.Parameter),
+			}
+
+			// fill service with arguments
+			if tc.in != nil && len(tc.in) > 0 {
+				for i, in := range tc.in {
+					service.Input[fmt.Sprintf("%d", i)] = in
+				}
+			}
+			if tc.out != nil && len(tc.out) > 0 {
+				for i, out := range tc.out {
+					service.Output[fmt.Sprintf("%d", i)] = out
+				}
+			}
+
+			s := BuildSignature(service)
+
+			err := s.ValidateInput(reflect.TypeOf(tc.fn))
+			if err != nil {
+				if !errors.Is(err, tc.err) {
+					t.Fatalf("expected the error <%s> got <%s>", tc.err, err)
+				}
+				return
+			}
+			err = s.ValidateOutput(reflect.TypeOf(tc.fn))
+			if err != nil {
+				if !errors.Is(err, tc.err) {
+					t.Fatalf("expected the error <%s> got <%s>", tc.err, err)
+				}
+				return
+			}
+
+			// no error encountered but expected 1
+			if tc.err != nil {
+				t.Fatalf("expected an error <%v>", tc.err)
+			}
+		})
+	}
+}

internal/multipart/component.go

@@ -13,19 +13,19 @@ func (comp *Component) parseHeaders(_raw []byte) error {
 	// 1. Extract lines
 	_lines := strings.Split(string(_raw), "\n")
 	if len(_lines) < 2 {
-		return ErrNoHeader
+		return errNoHeader
 	}
 
 	// 2. trim each line + remove 'Content-Disposition' prefix
 	header := strings.Trim(_lines[0], " \t\r")
 
 	if !strings.HasPrefix(header, "Content-Disposition: form-data;") {
-		return ErrNoHeader
+		return errNoHeader
 	}
 	header = strings.Trim(header[len("Content-Disposition: form-data;"):], " \t\r")
 
 	if len(header) < 1 {
-		return ErrNoHeader
+		return errNoHeader
 	}
 
 	// 3. Extract each key-value pair

internal/multipart/multipart.go

@@ -3,19 +3,18 @@ package multipart
 // cerr allows you to create constant "const" error with type boxing.
 type cerr string
 
-// Error implements the error builtin interface.
 func (err cerr) Error() string {
 	return string(err)
 }
 
-// ErrMissingDataName is set when a multipart variable/file has no name="..."
-const ErrMissingDataName = cerr("data has no name")
+// errMissingDataName is set when a multipart variable/file has no name="..."
+const errMissingDataName = cerr("data has no name")
 
-// ErrDataNameConflict is set when a multipart variable/file name is already used
-const ErrDataNameConflict = cerr("data name conflict")
+// errDataNameConflict is set when a multipart variable/file name is already used
+const errDataNameConflict = cerr("data name conflict")
 
-// ErrNoHeader is set when a multipart variable/file has no (valid) header
-const ErrNoHeader = cerr("data has no header")
+// errNoHeader is set when a multipart variable/file has no (valid) header
+const errNoHeader = cerr("data has no header")
 
 // Component represents a multipart variable/file
 type Component struct {

internal/multipart/reader.go

@@ -71,11 +71,11 @@ func (reader *Reader) Parse() error {
 
 		name := comp.GetHeader("name")
 		if len(name) < 1 {
-			return ErrMissingDataName
+			return errMissingDataName
 		}
 
 		if _, nameUsed := reader.Data[name]; nameUsed {
-			return ErrDataNameConflict
+			return errDataNameConflict
 		}
 
 		reader.Data[name] = comp

internal/multipart/reader_test.go

@@ -196,8 +196,8 @@ func TestNoName(t *testing.T) {
 				return
 			}
 
-			if err = mpr.Parse(); err != ErrMissingDataName {
-				t.Errorf("expected the error <%s>, got <%s>", ErrMissingDataName, err)
+			if err = mpr.Parse(); err != errMissingDataName {
+				t.Errorf("expected the error <%s>, got <%s>", errMissingDataName, err)
 				return
 			}
 		})
@@ -238,8 +238,8 @@ func TestNoHeader(t *testing.T) {
 				return
 			}
 
-			if err = mpr.Parse(); err != ErrNoHeader {
-				t.Errorf("expected the error <%s>, got <%s>", ErrNoHeader, err)
+			if err = mpr.Parse(); err != errNoHeader {
+				t.Errorf("expected the error <%s>, got <%s>", errNoHeader, err)
 				return
 			}
 		})
@@ -274,8 +274,8 @@ facebook.com
 		t.Fatalf("unexpected error <%s>", err)
 	}
 
-	if err = mpr.Parse(); err != ErrDataNameConflict {
-		t.Fatalf("expected the error <%s>, got <%s>", ErrDataNameConflict, err)
+	if err = mpr.Parse(); err != errDataNameConflict {
+		t.Fatalf("expected the error <%s>, got <%s>", errDataNameConflict, err)
 	}
 
 }

internal/reqdata/parse_parameter_test.go

@@ -1,6 +1,7 @@
 package reqdata
 
 import (
+	"fmt"
 	"math"
 	"testing"
 )
@@ -24,7 +25,7 @@ func TestSimpleFloat(t *testing.T) {
 	tcases := []float64{12.3456789, -12.3456789, 0.0000001, -0.0000001}
 
 	for i, tcase := range tcases {
-		t.Run("case "+string(i), func(t *testing.T) {
+		t.Run(fmt.Sprintf("case %d", i), func(t *testing.T) {
 			p := parseParameter(tcase)
 
 			cast, canCast := p.(float64)
@@ -45,7 +46,7 @@ func TestSimpleBool(t *testing.T) {
 	tcases := []bool{true, false}
 
 	for i, tcase := range tcases {
-		t.Run("case "+string(i), func(t *testing.T) {
+		t.Run(fmt.Sprintf("case %d", i), func(t *testing.T) {
 			p := parseParameter(tcase)
 
 			cast, canCast := p.(bool)
@@ -136,7 +137,7 @@ func TestJsonPrimitiveBool(t *testing.T) {
 	}
 
 	for i, tcase := range tcases {
-		t.Run("case "+string(i), func(t *testing.T) {
+		t.Run(fmt.Sprintf("case %d", i), func(t *testing.T) {
 			p := parseParameter(tcase.Raw)
 
 			cast, canCast := p.(bool)
@@ -173,7 +174,7 @@ func TestJsonPrimitiveFloat(t *testing.T) {
 	}
 
 	for i, tcase := range tcases {
-		t.Run("case "+string(i), func(t *testing.T) {
+		t.Run(fmt.Sprintf("case %d", i), func(t *testing.T) {
 			p := parseParameter(tcase.Raw)
 
 			cast, canCast := p.(float64)

internal/reqdata/set.go

@@ -6,40 +6,36 @@ import (
 	"io"
 	"reflect"
 
-	"git.xdrm.io/go/aicra/internal/config"
-	"git.xdrm.io/go/aicra/internal/multipart"
+	"github.com/xdrm-io/aicra/internal/config"
+	"github.com/xdrm-io/aicra/internal/multipart"
 
 	"net/http"
 	"strings"
 )
 
-// Set represents all data that can be caught:
+// T represents all data that can be caught from an http request for a specific
+// configuration Service; it features:
 // - URI (from the URI)
-// - GET (default url data)
+// - GET (standard url data)
 // - POST (from json, form-data, url-encoded)
 //   - 'application/json'                  => key-value pair is parsed as json into the map
 //   - 'application/x-www-form-urlencoded' => standard parameters as QUERY parameters
 //   - 'multipart/form-data'               => parse form-data format
-type Set struct {
+type T struct {
 	service *config.Service
-
-	// contains URL+GET+FORM data with prefixes:
-	// - FORM: no prefix
-	// - URL:  '{uri_var}'
-	// - GET:  'GET@' followed by the key in GET
-	Data map[string]interface{}
+	Data    map[string]interface{}
 }
 
 // New creates a new empty store.
-func New(service *config.Service) *Set {
-	return &Set{
+func New(service *config.Service) *T {
+	return &T{
 		service: service,
-		Data:    make(map[string]interface{}),
+		Data:    map[string]interface{}{},
 	}
 }
 
-// ExtractURI fills 'Set' with creating pointers inside 'Url'
-func (i *Set) ExtractURI(req *http.Request) error {
+// GetURI parameters
+func (i *T) GetURI(req http.Request) error {
 	uriparts := config.SplitURL(req.URL.RequestURI())
 
 	for _, capture := range i.service.Captures {
@@ -54,122 +50,115 @@ func (i *Set) ExtractURI(req *http.Request) error {
 			return fmt.Errorf("%s: %w", capture.Name, ErrUnknownType)
 		}
 
-		// parse parameter
 		parsed := parseParameter(value)
-
-		// check type
 		cast, valid := capture.Ref.Validator(parsed)
 		if !valid {
 			return fmt.Errorf("%s: %w", capture.Name, ErrInvalidType)
 		}
-
-		// store cast value in 'Set'
 		i.Data[capture.Ref.Rename] = cast
 	}
 
 	return nil
 }
 
-// ExtractQuery data from the url query parameters
-func (i *Set) ExtractQuery(req *http.Request) error {
+// GetQuery data from the url query parameters
+func (i *T) GetQuery(req http.Request) error {
 	query := req.URL.Query()
 
 	for name, param := range i.service.Query {
-		value, exist := query[name]
+		values, exist := query[name]
 
-		// fail on missing required
-		if !exist && !param.Optional {
-			return fmt.Errorf("%s: %w", name, ErrMissingRequiredParam)
-		}
-
-		// optional
 		if !exist {
+			if !param.Optional {
+				return fmt.Errorf("%s: %w", name, ErrMissingRequiredParam)
+			}
 			continue
 		}
 
-		// parse parameter
-		parsed := parseParameter(value)
+		var parsed interface{}
+
+		// consider element instead of slice or elements when only 1
+		if len(values) == 1 {
+			parsed = parseParameter(values[0])
+		} else { // consider slice
+			parsed = parseParameter(values)
+		}
 
-		// check type
 		cast, valid := param.Validator(parsed)
 		if !valid {
 			return fmt.Errorf("%s: %w", name, ErrInvalidType)
 		}
-
-		// store cast value
 		i.Data[param.Rename] = cast
 	}
 
 	return nil
 }
 
-// ExtractForm data from request
-//
+// GetForm parameters the from request
 // - parse 'form-data' if not supported for non-POST requests
 // - parse 'x-www-form-urlencoded'
 // - parse 'application/json'
-func (i *Set) ExtractForm(req *http.Request) error {
-
-	// ignore GET method
+func (i *T) GetForm(req http.Request) error {
 	if req.Method == http.MethodGet {
 		return nil
 	}
 
-	contentType := req.Header.Get("Content-Type")
+	ct := req.Header.Get("Content-Type")
+	switch {
+	case strings.HasPrefix(ct, "application/json"):
+		err := i.parseJSON(req)
+		if err != nil {
+			return err
+		}
 
-	// parse json
-	if strings.HasPrefix(contentType, "application/json") {
-		return i.parseJSON(req)
+	case strings.HasPrefix(ct, "application/x-www-form-urlencoded"):
+		err := i.parseUrlencoded(req)
+		if err != nil {
+			return err
+		}
+
+	case strings.HasPrefix(ct, "multipart/form-data; boundary="):
+		err := i.parseMultipart(req)
+		if err != nil {
+			return err
+		}
 	}
 
-	// parse urlencoded
-	if strings.HasPrefix(contentType, "application/x-www-form-urlencoded") {
-		return i.parseUrlencoded(req)
+	// fail on at least 1 mandatory form param when there is no body
+	for name, param := range i.service.Form {
+		_, exists := i.Data[param.Rename]
+		if !exists && !param.Optional {
+			return fmt.Errorf("%s: %w", name, ErrMissingRequiredParam)
+		}
 	}
-
-	// parse multipart
-	if strings.HasPrefix(contentType, "multipart/form-data; boundary=") {
-		return i.parseMultipart(req)
-	}
-
-	// nothing to parse
 	return nil
 }
 
 // parseJSON parses JSON from the request body inside 'Form'
 // and 'Set'
-func (i *Set) parseJSON(req *http.Request) error {
-
-	parsed := make(map[string]interface{}, 0)
+func (i *T) parseJSON(req http.Request) error {
+	var parsed map[string]interface{}
 
 	decoder := json.NewDecoder(req.Body)
-	if err := decoder.Decode(&parsed); err != nil {
-		if err == io.EOF {
-			return nil
-		}
+	err := decoder.Decode(&parsed)
+	if err == io.EOF {
+		return nil
+	}
+	if err != nil {
 		return fmt.Errorf("%s: %w", err, ErrInvalidJSON)
 	}
 
 	for name, param := range i.service.Form {
 		value, exist := parsed[name]
 
-		// fail on missing required
-		if !exist && !param.Optional {
-			return fmt.Errorf("%s: %w", name, ErrMissingRequiredParam)
-		}
-
-		// optional
 		if !exist {
 			continue
 		}
 
-		// fail on invalid type
 		cast, valid := param.Validator(value)
 		if !valid {
 			return fmt.Errorf("%s: %w", name, ErrInvalidType)
 		}
-
-		// store cast value
 		i.Data[param.Rename] = cast
 	}
 
@@ -178,35 +167,31 @@ func (i *Set) parseJSON(req *http.Request) error {
 
 // parseUrlencoded parses urlencoded from the request body inside 'Form'
 // and 'Set'
-func (i *Set) parseUrlencoded(req *http.Request) error {
-	// use http.Request interface
+func (i *T) parseUrlencoded(req http.Request) error {
 	if err := req.ParseForm(); err != nil {
 		return err
 	}
 
 	for name, param := range i.service.Form {
-		value, exist := req.PostForm[name]
+		values, exist := req.PostForm[name]
 
-		// fail on missing required
-		if !exist && !param.Optional {
-			return fmt.Errorf("%s: %w", name, ErrMissingRequiredParam)
-		}
-
-		// optional
 		if !exist {
 			continue
 		}
 
-		// parse parameter
-		parsed := parseParameter(value)
+		var parsed interface{}
+
+		// consider element instead of slice or elements when only 1
+		if len(values) == 1 {
+			parsed = parseParameter(values[0])
+		} else { // consider slice
+			parsed = parseParameter(values)
+		}
 
-		// check type
 		cast, valid := param.Validator(parsed)
 		if !valid {
 			return fmt.Errorf("%s: %w", name, ErrInvalidType)
 		}
-
-		// store cast value
 		i.Data[param.Rename] = cast
 	}
 
@@ -215,46 +200,33 @@ func (i *Set) parseUrlencoded(req *http.Request) error {
 
 // parseMultipart parses multi-part from the request body inside 'Form'
 // and 'Set'
-func (i *Set) parseMultipart(req *http.Request) error {
-
-	// 1. create reader
+func (i *T) parseMultipart(req http.Request) error {
 	boundary := req.Header.Get("Content-Type")[len("multipart/form-data; boundary="):]
 	mpr, err := multipart.NewReader(req.Body, boundary)
+	if err == io.EOF {
+		return nil
+	}
 	if err != nil {
-		if err == io.EOF {
-			return nil
-		}
-		return err
+		return fmt.Errorf("%s: %w", err, ErrInvalidMultipart)
 	}
 
-	// 2. parse multipart
-	if err = mpr.Parse(); err != nil {
+	err = mpr.Parse()
+	if err != nil {
 		return fmt.Errorf("%s: %w", err, ErrInvalidMultipart)
 	}
 
 	for name, param := range i.service.Form {
 		component, exist := mpr.Data[name]
 
-		// fail on missing required
-		if !exist && !param.Optional {
-			return fmt.Errorf("%s: %w", name, ErrMissingRequiredParam)
-		}
-
-		// optional
 		if !exist {
 			continue
 		}
 
-		// parse parameter
 		parsed := parseParameter(string(component.Data))
-
-		// fail on invalid type
 		cast, valid := param.Validator(parsed)
 		if !valid {
 			return fmt.Errorf("%s: %w", name, ErrInvalidType)
 		}
-
-		// store cast value
 		i.Data[param.Rename] = cast
 	}
 
@@ -266,58 +238,47 @@ func (i *Set) parseMultipart(req *http.Request) error {
 // - []string : return array of json elements
 // - string   : return json if valid, else return raw string
 func parseParameter(data interface{}) interface{} {
-	dtype := reflect.TypeOf(data)
-	dvalue := reflect.ValueOf(data)
+	rt := reflect.TypeOf(data)
+	rv := reflect.ValueOf(data)
 
-	switch dtype.Kind() {
+	switch rt.Kind() {
 
-	/* (1) []string -> recursive */
+	// []string -> recursive
 	case reflect.Slice:
-
-		// 1. ignore empty
-		if dvalue.Len() == 0 {
+		if rv.Len() == 0 {
 			return data
 		}
 
-		// 2. parse each element recursively
-		result := make([]interface{}, dvalue.Len())
-
-		for i, l := 0, dvalue.Len(); i < l; i++ {
-			element := dvalue.Index(i)
-			result[i] = parseParameter(element.Interface())
+		slice := make([]interface{}, rv.Len())
+		for i, l := 0, rv.Len(); i < l; i++ {
+			element := rv.Index(i)
+			slice[i] = parseParameter(element.Interface())
 		}
-		return result
+		return slice
 
-	/* (2) string -> parse */
+	// string -> parse as json
+	// keep as string if invalid json
 	case reflect.String:
-
-		// build json wrapper
-		wrapper := fmt.Sprintf("{\"wrapped\":%s}", dvalue.String())
-
-		// try to parse as json
-		var result interface{}
-		err := json.Unmarshal([]byte(wrapper), &result)
-
-		// return if success
+		var cast interface{}
+		wrapper := fmt.Sprintf("{\"wrapped\":%s}", rv.String())
+		err := json.Unmarshal([]byte(wrapper), &cast)
 		if err != nil {
-			return dvalue.String()
+			return rv.String()
 		}
 
-		mapval, ok := result.(map[string]interface{})
+		mapval, ok := cast.(map[string]interface{})
 		if !ok {
-			return dvalue.String()
+			return rv.String()
 		}
 
 		wrapped, ok := mapval["wrapped"]
 		if !ok {
-			return dvalue.String()
+			return rv.String()
 		}
-
 		return wrapped
 
+	// any type -> unchanged
+	default:
+		return rv.Interface()
 	}
-
-	/* (3) NIL if unknown type */
-	return dvalue.Interface()
-
 }

internal/reqdata/set_test.go

@@ -10,7 +10,7 @@ import (
 	"strings"
 	"testing"
 
-	"git.xdrm.io/go/aicra/internal/config"
+	"github.com/xdrm-io/aicra/internal/config"
 )
 
 func getEmptyService() *config.Service {
@@ -131,17 +131,15 @@ func TestStoreWithUri(t *testing.T) {
 			store := New(service)
 
 			req := httptest.NewRequest(http.MethodGet, "http://host.com"+test.URI, nil)
-			err := store.ExtractURI(req)
+			err := store.GetURI(*req)
 			if err != nil {
 				if test.Err != nil {
 					if !errors.Is(err, test.Err) {
-						t.Errorf("expected error <%s>, got <%s>", test.Err, err)
-						t.FailNow()
+						t.Fatalf("expected error <%s>, got <%s>", test.Err, err)
 					}
 					return
 				}
-				t.Errorf("unexpected error <%s>", err)
-				t.FailNow()
+				t.Fatalf("unexpected error <%s>", err)
 			}
 
 			if len(store.Data) != len(service.Input) {
@@ -183,14 +181,14 @@ func TestExtractQuery(t *testing.T) {
 			Query:        "a",
 			Err:          nil,
 			ParamNames:   []string{"a"},
-			ParamValues:  [][]string{[]string{""}},
+			ParamValues:  [][]string{{""}},
 		},
 		{
 			ServiceParam: []string{"a"},
 			Query:        "a&b",
 			Err:          nil,
 			ParamNames:   []string{"a"},
-			ParamValues:  [][]string{[]string{""}},
+			ParamValues:  [][]string{{""}},
 		},
 		{
 			ServiceParam: []string{"a", "missing"},
@@ -204,61 +202,58 @@ func TestExtractQuery(t *testing.T) {
 			Query:        "a&b",
 			Err:          nil,
 			ParamNames:   []string{"a", "b"},
-			ParamValues:  [][]string{[]string{""}, []string{""}},
+			ParamValues:  [][]string{{""}, {""}},
 		},
 		{
 			ServiceParam: []string{"a"},
 			Err:          nil,
 			Query:        "a=",
 			ParamNames:   []string{"a"},
-			ParamValues:  [][]string{[]string{""}},
+			ParamValues:  [][]string{{""}},
 		},
 		{
 			ServiceParam: []string{"a", "b"},
 			Err:          nil,
 			Query:        "a=&b=x",
 			ParamNames:   []string{"a", "b"},
-			ParamValues:  [][]string{[]string{""}, []string{"x"}},
+			ParamValues:  [][]string{{""}, {"x"}},
 		},
 		{
 			ServiceParam: []string{"a", "c"},
 			Err:          nil,
 			Query:        "a=b&c=d",
 			ParamNames:   []string{"a", "c"},
-			ParamValues:  [][]string{[]string{"b"}, []string{"d"}},
+			ParamValues:  [][]string{{"b"}, {"d"}},
 		},
 		{
 			ServiceParam: []string{"a", "c"},
 			Err:          nil,
 			Query:        "a=b&c=d&a=x",
 			ParamNames:   []string{"a", "c"},
-			ParamValues:  [][]string{[]string{"b", "x"}, []string{"d"}},
+			ParamValues:  [][]string{{"b", "x"}, {"d"}},
 		},
 	}
 
 	for i, test := range tests {
-		t.Run(fmt.Sprintf("request.%d", i), func(t *testing.T) {
+		t.Run(fmt.Sprintf("request[%d]", i), func(t *testing.T) {
 
 			store := New(getServiceWithQuery(test.ServiceParam...))
 
 			req := httptest.NewRequest(http.MethodGet, fmt.Sprintf("http://host.com?%s", test.Query), nil)
-			err := store.ExtractQuery(req)
+			err := store.GetQuery(*req)
 			if err != nil {
 				if test.Err != nil {
 					if !errors.Is(err, test.Err) {
-						t.Errorf("expected error <%s>, got <%s>", test.Err, err)
-						t.FailNow()
+						t.Fatalf("expected error <%s>, got <%s>", test.Err, err)
 					}
 					return
 				}
-				t.Errorf("unexpected error <%s>", err)
-				t.FailNow()
+				t.Fatalf("unexpected error <%s>", err)
 			}
 
 			if test.ParamNames == nil || test.ParamValues == nil {
 				if len(store.Data) != 0 {
-					t.Errorf("expected no GET parameters and got %d", len(store.Data))
-					t.FailNow()
+					t.Fatalf("expected no GET parameters and got %d", len(store.Data))
 				}
 
 				// no param to check
@@ -266,8 +261,7 @@ func TestExtractQuery(t *testing.T) {
 			}
 
 			if len(test.ParamNames) != len(test.ParamValues) {
-				t.Errorf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
-				t.FailNow()
+				t.Fatalf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
 			}
 
 			for pi, pName := range test.ParamNames {
@@ -276,29 +270,35 @@ func TestExtractQuery(t *testing.T) {
 				t.Run(pName, func(t *testing.T) {
 					param, isset := store.Data[pName]
 					if !isset {
-						t.Errorf("param does not exist")
-						t.FailNow()
+						t.Fatalf("param does not exist")
 					}
 
+					// single value, should return a single element
+					if len(values) == 1 {
+						cast, canCast := param.(string)
+						if !canCast {
+							t.Fatalf("should return a string (got '%v')", cast)
+						}
+						if values[0] != cast {
+							t.Fatalf("should return '%s' (got '%s')", values[0], cast)
+						}
+						return
+					}
+
+					// multiple values, should return a slice
 					cast, canCast := param.([]interface{})
 					if !canCast {
-						t.Errorf("should return a []string (got '%v')", cast)
-						t.FailNow()
+						t.Fatalf("should return a []string (got '%v')", cast)
 					}
 
 					if len(cast) != len(values) {
-						t.Errorf("should return %d string(s) (got '%d')", len(values), len(cast))
-						t.FailNow()
+						t.Fatalf("should return %d string(s) (got '%d')", len(values), len(cast))
 					}
 
 					for vi, value := range values {
-
-						t.Run(fmt.Sprintf("value.%d", vi), func(t *testing.T) {
-							if value != cast[vi] {
-								t.Errorf("should return '%s' (got '%s')", value, cast[vi])
-								t.FailNow()
-							}
-						})
+						if value != cast[vi] {
+							t.Fatalf("should return '%s' (got '%s')", value, cast[vi])
+						}
 					}
 				})
 
@@ -324,11 +324,9 @@ func TestStoreWithUrlEncodedFormParseError(t *testing.T) {
 
 	// defer req.Body.Close()
 	store := New(nil)
-	err := store.ExtractForm(req)
+	err := store.GetForm(*req)
 	if err == nil {
-		t.Errorf("expected malformed urlencoded to have FailNow being parsed (got %d elements)", len(store.Data))
-		t.FailNow()
-
+		t.Fatalf("expected malformed urlencoded to have FailNow being parsed (got %d elements)", len(store.Data))
 	}
 }
 func TestExtractFormUrlEncoded(t *testing.T) {
@@ -359,14 +357,14 @@ func TestExtractFormUrlEncoded(t *testing.T) {
 			URLEncoded:    "a",
 			Err:           nil,
 			ParamNames:    []string{"a"},
-			ParamValues:   [][]string{[]string{""}},
+			ParamValues:   [][]string{{""}},
 		},
 		{
 			ServiceParams: []string{"a"},
 			URLEncoded:    "a&b",
 			Err:           nil,
 			ParamNames:    []string{"a"},
-			ParamValues:   [][]string{[]string{""}},
+			ParamValues:   [][]string{{""}},
 		},
 		{
 			ServiceParams: []string{"a", "missing"},
@@ -380,35 +378,35 @@ func TestExtractFormUrlEncoded(t *testing.T) {
 			URLEncoded:    "a&b",
 			Err:           nil,
 			ParamNames:    []string{"a", "b"},
-			ParamValues:   [][]string{[]string{""}, []string{""}},
+			ParamValues:   [][]string{{""}, {""}},
 		},
 		{
 			ServiceParams: []string{"a"},
 			Err:           nil,
 			URLEncoded:    "a=",
 			ParamNames:    []string{"a"},
-			ParamValues:   [][]string{[]string{""}},
+			ParamValues:   [][]string{{""}},
 		},
 		{
 			ServiceParams: []string{"a", "b"},
 			Err:           nil,
 			URLEncoded:    "a=&b=x",
 			ParamNames:    []string{"a", "b"},
-			ParamValues:   [][]string{[]string{""}, []string{"x"}},
+			ParamValues:   [][]string{{""}, {"x"}},
 		},
 		{
 			ServiceParams: []string{"a", "c"},
 			Err:           nil,
 			URLEncoded:    "a=b&c=d",
 			ParamNames:    []string{"a", "c"},
-			ParamValues:   [][]string{[]string{"b"}, []string{"d"}},
+			ParamValues:   [][]string{{"b"}, {"d"}},
 		},
 		{
 			ServiceParams: []string{"a", "c"},
 			Err:           nil,
 			URLEncoded:    "a=b&c=d&a=x",
 			ParamNames:    []string{"a", "c"},
-			ParamValues:   [][]string{[]string{"b", "x"}, []string{"d"}},
+			ParamValues:   [][]string{{"b", "x"}, {"d"}},
 		},
 	}
 
@@ -420,23 +418,20 @@ func TestExtractFormUrlEncoded(t *testing.T) {
 			defer req.Body.Close()
 
 			store := New(getServiceWithForm(test.ServiceParams...))
-			err := store.ExtractForm(req)
+			err := store.GetForm(*req)
 			if err != nil {
 				if test.Err != nil {
 					if !errors.Is(err, test.Err) {
-						t.Errorf("expected error <%s>, got <%s>", test.Err, err)
-						t.FailNow()
+						t.Fatalf("expected error <%s>, got <%s>", test.Err, err)
 					}
 					return
 				}
-				t.Errorf("unexpected error <%s>", err)
-				t.FailNow()
+				t.Fatalf("unexpected error <%s>", err)
 			}
 
 			if test.ParamNames == nil || test.ParamValues == nil {
 				if len(store.Data) != 0 {
-					t.Errorf("expected no GET parameters and got %d", len(store.Data))
-					t.FailNow()
+					t.Fatalf("expected no GET parameters and got %d", len(store.Data))
 				}
 
 				// no param to check
@@ -444,8 +439,7 @@ func TestExtractFormUrlEncoded(t *testing.T) {
 			}
 
 			if len(test.ParamNames) != len(test.ParamValues) {
-				t.Errorf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
-				t.FailNow()
+				t.Fatalf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
 			}
 
 			for pi, key := range test.ParamNames {
@@ -454,29 +448,35 @@ func TestExtractFormUrlEncoded(t *testing.T) {
 				t.Run(key, func(t *testing.T) {
 					param, isset := store.Data[key]
 					if !isset {
-						t.Errorf("param does not exist")
-						t.FailNow()
+						t.Fatalf("param does not exist")
 					}
 
+					// single value, should return a single element
+					if len(values) == 1 {
+						cast, canCast := param.(string)
+						if !canCast {
+							t.Fatalf("should return a string (got '%v')", cast)
+						}
+						if values[0] != cast {
+							t.Fatalf("should return '%s' (got '%s')", values[0], cast)
+						}
+						return
+					}
+
+					// multiple values, should return a slice
 					cast, canCast := param.([]interface{})
 					if !canCast {
-						t.Errorf("should return a []interface{} (got '%v')", cast)
-						t.FailNow()
+						t.Fatalf("should return a []string (got '%v')", cast)
 					}
 
 					if len(cast) != len(values) {
-						t.Errorf("should return %d string(s) (got '%d')", len(values), len(cast))
-						t.FailNow()
+						t.Fatalf("should return %d string(s) (got '%d')", len(values), len(cast))
 					}
 
 					for vi, value := range values {
-
-						t.Run(fmt.Sprintf("value.%d", vi), func(t *testing.T) {
-							if value != cast[vi] {
-								t.Errorf("should return '%s' (got '%s')", value, cast[vi])
-								t.FailNow()
-							}
-						})
+						if value != cast[vi] {
+							t.Fatalf("should return '%s' (got '%s')", value, cast[vi])
+						}
 					}
 				})
 
@@ -563,23 +563,20 @@ func TestJsonParameters(t *testing.T) {
 			defer req.Body.Close()
 			store := New(getServiceWithForm(test.ServiceParams...))
 
-			err := store.ExtractForm(req)
+			err := store.GetForm(*req)
 			if err != nil {
 				if test.Err != nil {
 					if !errors.Is(err, test.Err) {
-						t.Errorf("expected error <%s>, got <%s>", test.Err, err)
-						t.FailNow()
+						t.Fatalf("expected error <%s>, got <%s>", test.Err, err)
 					}
 					return
 				}
-				t.Errorf("unexpected error <%s>", err)
-				t.FailNow()
+				t.Fatalf("unexpected error <%s>", err)
 			}
 
 			if test.ParamNames == nil || test.ParamValues == nil {
 				if len(store.Data) != 0 {
-					t.Errorf("expected no JSON parameters and got %d", len(store.Data))
-					t.FailNow()
+					t.Fatalf("expected no JSON parameters and got %d", len(store.Data))
 				}
 
 				// no param to check
@@ -587,8 +584,7 @@ func TestJsonParameters(t *testing.T) {
 			}
 
 			if len(test.ParamNames) != len(test.ParamValues) {
-				t.Errorf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
-				t.FailNow()
+				t.Fatalf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
 			}
 
 			for pi, pName := range test.ParamNames {
@@ -599,8 +595,7 @@ func TestJsonParameters(t *testing.T) {
 
 					param, isset := store.Data[key]
 					if !isset {
-						t.Errorf("store should contain element with key '%s'", key)
-						t.FailNow()
+						t.Fatalf("store should contain element with key '%s'", key)
 						return
 					}
 
@@ -610,13 +605,11 @@ func TestJsonParameters(t *testing.T) {
 					paramValueType := reflect.TypeOf(param)
 
 					if valueType != paramValueType {
-						t.Errorf("should be of type %v (got '%v')", valueType, paramValueType)
-						t.FailNow()
+						t.Fatalf("should be of type %v (got '%v')", valueType, paramValueType)
 					}
 
 					if paramValue != value {
-						t.Errorf("should return %v (got '%v')", value, paramValue)
-						t.FailNow()
+						t.Fatalf("should return %v (got '%v')", value, paramValue)
 					}
 
 				})
@@ -720,23 +713,20 @@ x
 			defer req.Body.Close()
 			store := New(getServiceWithForm(test.ServiceParams...))
 
-			err := store.ExtractForm(req)
+			err := store.GetForm(*req)
 			if err != nil {
 				if test.Err != nil {
 					if !errors.Is(err, test.Err) {
-						t.Errorf("expected error <%s>, got <%s>", test.Err, err)
-						t.FailNow()
+						t.Fatalf("expected error <%s>, got <%s>", test.Err, err)
 					}
 					return
 				}
-				t.Errorf("unexpected error <%s>", err)
-				t.FailNow()
+				t.Fatalf("unexpected error <%s>", err)
 			}
 
 			if test.ParamNames == nil || test.ParamValues == nil {
 				if len(store.Data) != 0 {
-					t.Errorf("expected no JSON parameters and got %d", len(store.Data))
-					t.FailNow()
+					t.Fatalf("expected no JSON parameters and got %d", len(store.Data))
 				}
 
 				// no param to check
@@ -744,8 +734,7 @@ x
 			}
 
 			if len(test.ParamNames) != len(test.ParamValues) {
-				t.Errorf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
-				t.FailNow()
+				t.Fatalf("invalid test: names and values differ in size (%d vs %d)", len(test.ParamNames), len(test.ParamValues))
 			}
 
 			for pi, key := range test.ParamNames {
@@ -755,8 +744,7 @@ x
 
 					param, isset := store.Data[key]
 					if !isset {
-						t.Errorf("store should contain element with key '%s'", key)
-						t.FailNow()
+						t.Fatalf("store should contain element with key '%s'", key)
 						return
 					}
 
@@ -766,13 +754,11 @@ x
 					paramValueType := reflect.TypeOf(param)
 
 					if valueType != paramValueType {
-						t.Errorf("should be of type %v (got '%v')", valueType, paramValueType)
-						t.FailNow()
+						t.Fatalf("should be of type %v (got '%v')", valueType, paramValueType)
 					}
 
 					if paramValue != value {
-						t.Errorf("should return %v (got '%v')", value, paramValue)
-						t.FailNow()
+						t.Fatalf("should return %v (got '%v')", value, paramValue)
 					}
 
 				})

response.go

@@ -0,0 +1,60 @@
+package aicra
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/xdrm-io/aicra/api"
+)
+
+// response for an service call
+type response struct {
+	Data   map[string]interface{}
+	Status int
+	err    api.Err
+}
+
+// newResponse creates an empty response.
+func newResponse() *response {
+	return &response{
+		Status: http.StatusOK,
+		Data:   make(map[string]interface{}),
+		err:    api.ErrFailure,
+	}
+}
+
+// WithError sets the response error
+func (r *response) WithError(err api.Err) *response {
+	r.err = err
+	return r
+}
+
+// WithValue sets a response value
+func (r *response) WithValue(name string, value interface{}) *response {
+	r.Data[name] = value
+	return r
+}
+
+// MarshalJSON generates the JSON representation of the response
+//
+// implements json.Marshaler
+func (r *response) MarshalJSON() ([]byte, error) {
+	fmt := make(map[string]interface{})
+	for k, v := range r.Data {
+		fmt[k] = v
+	}
+	fmt["error"] = r.err
+	return json.Marshal(fmt)
+}
+
+// ServeHTTP writes the response representation back to the http.ResponseWriter
+//
+// implements http.Handler
+func (res *response) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
+	w.WriteHeader(res.err.Status)
+	encoded, err := json.Marshal(res)
+	if err == nil {
+		w.Write(encoded)
+	}
+	return err
+}

response_test.go

@@ -0,0 +1,95 @@
+package aicra
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"github.com/xdrm-io/aicra/api"
+)
+
+func printEscaped(raw string) string {
+	raw = strings.ReplaceAll(raw, "\n", "\\n")
+	raw = strings.ReplaceAll(raw, "\r", "\\r")
+	return raw
+}
+
+func TestResponseJSON(t *testing.T) {
+	t.Parallel()
+
+	tt := []struct {
+		name string
+		err  api.Err
+		data map[string]interface{}
+		json string
+	}{
+		{
+			name: "empty success response",
+			err:  api.ErrSuccess,
+			data: map[string]interface{}{},
+			json: `{"error":{"code":0,"reason":"all right"}}`,
+		},
+		{
+			name: "empty failure response",
+			err:  api.ErrFailure,
+			data: map[string]interface{}{},
+			json: `{"error":{"code":1,"reason":"it failed"}}`,
+		},
+		{
+			name: "empty unknown error response",
+			err:  api.ErrUnknown,
+			data: map[string]interface{}{},
+			json: `{"error":{"code":-1,"reason":"unknown error"}}`,
+		},
+		{
+			name: "success with data before err",
+			err:  api.ErrSuccess,
+			data: map[string]interface{}{"a": 12},
+			json: `{"a":12,"error":{"code":0,"reason":"all right"}}`,
+		},
+		{
+			name: "success with data right before err",
+			err:  api.ErrSuccess,
+			data: map[string]interface{}{"e": 12},
+			json: `{"e":12,"error":{"code":0,"reason":"all right"}}`,
+		},
+		{
+			name: "success with data right after err",
+			err:  api.ErrSuccess,
+			data: map[string]interface{}{"f": 12},
+			json: `{"error":{"code":0,"reason":"all right"},"f":12}`,
+		},
+		{
+			name: "success with data after err",
+			err:  api.ErrSuccess,
+			data: map[string]interface{}{"z": 12},
+			json: `{"error":{"code":0,"reason":"all right"},"z":12}`,
+		},
+		{
+			name: "success with data around err",
+			err:  api.ErrSuccess,
+			data: map[string]interface{}{"d": "before", "f": "after"},
+			json: `{"d":"before","error":{"code":0,"reason":"all right"},"f":"after"}`,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			res := newResponse().WithError(tc.err)
+			for k, v := range tc.data {
+				res.WithValue(k, v)
+			}
+
+			raw, err := json.Marshal(res)
+			if err != nil {
+				t.Fatalf("cannot marshal to json: %s", err)
+			}
+
+			if string(raw) != tc.json {
+				t.Fatalf("mismatching json:\nexpect: %v\nactual: %v", printEscaped(tc.json), printEscaped(string(raw)))
+			}
+
+		})
+	}
+
+}

server.go

@@ -1,91 +0,0 @@
-package aicra
-
-import (
-	"fmt"
-	"io"
-	"os"
-
-	"git.xdrm.io/go/aicra/datatype"
-	"git.xdrm.io/go/aicra/dynamic"
-	"git.xdrm.io/go/aicra/internal/config"
-)
-
-// Server represents an AICRA instance featuring: type checkers, services
-type Server struct {
-	config   *config.Server
-	handlers []*handler
-}
-
-// New creates a framework instance from a configuration file
-func New(configPath string, dtypes ...datatype.T) (*Server, error) {
-	var (
-		err        error
-		configFile io.ReadCloser
-	)
-
-	// 1. init instance
-	var i = &Server{
-		config:   nil,
-		handlers: make([]*handler, 0),
-	}
-
-	// 2. open config file
-	configFile, err = os.Open(configPath)
-	if err != nil {
-		return nil, err
-	}
-	defer configFile.Close()
-
-	// 3. load configuration
-	i.config, err = config.Parse(configFile, dtypes...)
-	if err != nil {
-		return nil, err
-	}
-
-	return i, nil
-
-}
-
-// Handle sets a new handler for an HTTP method to a path
-func (s *Server) Handle(method, path string, fn dynamic.HandlerFn) error {
-	// find associated service
-	var found *config.Service = nil
-	for _, service := range s.config.Services {
-		if method == service.Method && path == service.Pattern {
-			found = service
-			break
-		}
-	}
-	if found == nil {
-		return fmt.Errorf("%s '%s': %w", method, path, ErrNoServiceForHandler)
-	}
-
-	handler, err := createHandler(method, path, *found, fn)
-	if err != nil {
-		return err
-	}
-	s.handlers = append(s.handlers, handler)
-	return nil
-}
-
-// ToHTTPServer converts the server to a http server
-func (s Server) ToHTTPServer() (*httpServer, error) {
-
-	// check if handlers are missing
-	for _, service := range s.config.Services {
-		found := false
-		for _, handler := range s.handlers {
-			if handler.Method == service.Method && handler.Path == service.Pattern {
-				found = true
-				break
-			}
-		}
-		if !found {
-			return nil, fmt.Errorf("%s '%s': %w", service.Method, service.Pattern, ErrNoHandlerForService)
-		}
-	}
-
-	// 2. cast to http server
-	httpServer := httpServer(s)
-	return &httpServer, nil
-}

util.go

@@ -1,15 +0,0 @@
-package aicra
-
-import (
-	"log"
-	"net/http"
-
-	"git.xdrm.io/go/aicra/api"
-)
-
-var handledMethods = []string{http.MethodGet, http.MethodPost, http.MethodPut, http.MethodDelete}
-
-// Prints an error as HTTP response
-func logError(res *api.Response) {
-	log.Printf("[http.fail] %v\n", res)
-}

validator/any.go

@@ -0,0 +1,24 @@
+package validator
+
+import (
+	"reflect"
+)
+
+// AnyType makes the "any" type available in the aicra configuration
+// It considers valid any value
+type AnyType struct{}
+
+// GoType returns the interface{} type
+func (AnyType) GoType() reflect.Type {
+	return reflect.TypeOf(interface{}(nil))
+}
+
+// Validator that considers any value valid
+func (AnyType) Validator(typename string, avail ...Type) ValidateFunc {
+	if typename != "any" {
+		return nil
+	}
+	return func(value interface{}) (interface{}, bool) {
+		return value, true
+	}
+}

validator/any_test.go

@@ -1,16 +1,29 @@
-package builtin_test
+package validator_test
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
+func TestAny_ReflectType(t *testing.T) {
+	t.Parallel()
+
+	var (
+		dt       = validator.AnyType{}
+		expected = reflect.TypeOf(interface{}(nil))
+	)
+	if dt.GoType() != expected {
+		t.Fatalf("invalid GoType() %v ; expected %v", dt.GoType(), expected)
+	}
+}
+
 func TestAny_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	dt := builtin.AnyDataType{}
+	dt := validator.AnyType{}
 
 	tests := []struct {
 		Type    string
@@ -26,7 +39,7 @@ func TestAny_AvailableTypes(t *testing.T) {
 	}
 
 	for _, test := range tests {
-		validator := dt.Build(test.Type)
+		validator := dt.Validator(test.Type)
 
 		if validator == nil {
 			if test.Handled {
@@ -47,7 +60,7 @@ func TestAny_AlwaysTrue(t *testing.T) {
 
 	const typeName = "any"
 
-	validator := builtin.AnyDataType{}.Build(typeName)
+	validator := validator.AnyType{}.Validator(typeName)
 	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()

validator/bool.go

@@ -1,23 +1,24 @@
-package builtin
+package validator
 
 import (
 	"reflect"
-
-	"git.xdrm.io/go/aicra/datatype"
 )
 
-// BoolDataType is what its name tells
-type BoolDataType struct{}
+// BoolType makes the "bool" type available in the aicra configuration
+// It considers valid:
+// - booleans
+// - strings containing "true" or "false"
+// - []byte containing "true" or "false"
+type BoolType struct{}
 
-// Type returns the type of data
-func (BoolDataType) Type() reflect.Type {
+// GoType returns the `bool` type
+func (BoolType) GoType() reflect.Type {
 	return reflect.TypeOf(true)
 }
 
-// Build returns the validator
-func (BoolDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
-	// nothing if type not handled
-	if typeName != "bool" {
+// Validator for bool values
+func (BoolType) Validator(typename string, avail ...Type) ValidateFunc {
+	if typename != "bool" {
 		return nil
 	}
 

validator/bool_test.go

@@ -1,16 +1,29 @@
-package builtin_test
+package validator_test
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
+func TestBool_ReflectType(t *testing.T) {
+	t.Parallel()
+
+	var (
+		dt       = validator.BoolType{}
+		expected = reflect.TypeOf(true)
+	)
+	if dt.GoType() != expected {
+		t.Fatalf("invalid GoType() %v ; expected %v", dt.GoType(), expected)
+	}
+}
+
 func TestBool_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	dt := builtin.BoolDataType{}
+	dt := validator.BoolType{}
 
 	tests := []struct {
 		Type    string
@@ -26,7 +39,7 @@ func TestBool_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			validator := dt.Build(test.Type)
+			validator := dt.Validator(test.Type)
 			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
@@ -49,7 +62,7 @@ func TestBool_Values(t *testing.T) {
 
 	const typeName = "bool"
 
-	validator := builtin.BoolDataType{}.Build(typeName)
+	validator := validator.BoolType{}.Validator(typeName)
 	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()

validator/float.go

@@ -1,24 +1,27 @@
-package builtin
+package validator
 
 import (
 	"encoding/json"
 	"reflect"
-
-	"git.xdrm.io/go/aicra/datatype"
 )
 
-// FloatDataType is what its name tells
-type FloatDataType struct{}
+// FloatType makes the "float" (or "float64") type available in the aicra configuration
+// It considers valid:
+// - float64
+// - int (since it does not overflow)
+// - uint (since it does not overflow)
+// - strings containing json-compatible floats
+// - []byte containing json-compatible floats
+type FloatType struct{}
 
-// Type returns the type of data
-func (FloatDataType) Type() reflect.Type {
+// GoType returns the `float64` type
+func (FloatType) GoType() reflect.Type {
 	return reflect.TypeOf(float64(0))
 }
 
-// Build returns the validator
-func (FloatDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
-	// nothing if type not handled
-	if typeName != "float64" && typeName != "float" {
+// Validator for float64 values
+func (FloatType) Validator(typename string, avail ...Type) ValidateFunc {
+	if typename != "float64" && typename != "float" {
 		return nil
 	}
 	return func(value interface{}) (interface{}, bool) {

validator/float_test.go

@@ -1,17 +1,30 @@
-package builtin_test
+package validator_test
 
 import (
 	"fmt"
 	"math"
+	"reflect"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
+func TestFloat64_ReflectType(t *testing.T) {
+	t.Parallel()
+
+	var (
+		dt       = validator.FloatType{}
+		expected = reflect.TypeOf(float64(0.0))
+	)
+	if dt.GoType() != expected {
+		t.Fatalf("invalid GoType() %v ; expected %v", dt.GoType(), expected)
+	}
+}
+
 func TestFloat64_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	dt := builtin.FloatDataType{}
+	dt := validator.FloatType{}
 
 	tests := []struct {
 		Type    string
@@ -33,7 +46,7 @@ func TestFloat64_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			validator := dt.Build(test.Type)
+			validator := dt.Validator(test.Type)
 			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
@@ -56,7 +69,7 @@ func TestFloat64_Values(t *testing.T) {
 
 	const typeName = "float"
 
-	validator := builtin.FloatDataType{}.Build(typeName)
+	validator := validator.FloatType{}.Validator(typeName)
 	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()

validator/int.go

@@ -1,25 +1,29 @@
-package builtin
+package validator
 
 import (
 	"encoding/json"
 	"math"
 	"reflect"
-
-	"git.xdrm.io/go/aicra/datatype"
 )
 
-// IntDataType is what its name tells
-type IntDataType struct{}
+// IntType makes the "int" type available in the aicra configuration
+// It considers valid:
+// - int
+// - float64 (since it does not overflow)
+// - uint (since it does not overflow)
+// - strings containing json-compatible integers
+// - []byte containing json-compatible integers
+type IntType struct{}
 
-// Type returns the type of data
-func (IntDataType) Type() reflect.Type {
+// GoType returns the `int` type
+func (IntType) GoType() reflect.Type {
 	return reflect.TypeOf(int(0))
 }
 
-// Build returns the validator
-func (IntDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
+// Validator for int values
+func (IntType) Validator(typename string, avail ...Type) ValidateFunc {
 	// nothing if type not handled
-	if typeName != "int" {
+	if typename != "int" {
 		return nil
 	}
 

validator/int_test.go

@@ -1,17 +1,30 @@
-package builtin_test
+package validator_test
 
 import (
 	"fmt"
 	"math"
+	"reflect"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
+func TestInt_ReflectType(t *testing.T) {
+	t.Parallel()
+
+	var (
+		dt       = validator.IntType{}
+		expected = reflect.TypeOf(int(0))
+	)
+	if dt.GoType() != expected {
+		t.Fatalf("invalid GoType() %v ; expected %v", dt.GoType(), expected)
+	}
+}
+
 func TestInt_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	dt := builtin.IntDataType{}
+	dt := validator.IntType{}
 
 	tests := []struct {
 		Type    string
@@ -27,7 +40,7 @@ func TestInt_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			validator := dt.Build(test.Type)
+			validator := dt.Validator(test.Type)
 			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
@@ -50,7 +63,7 @@ func TestInt_Values(t *testing.T) {
 
 	const typeName = "int"
 
-	validator := builtin.IntDataType{}.Build(typeName)
+	validator := validator.IntType{}.Validator(typeName)
 	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
@@ -71,7 +84,7 @@ func TestInt_Values(t *testing.T) {
 		{uint(math.MaxInt64 + 1), false},
 
 		{float64(math.MinInt64), true},
-		// we cannot just substract 1 because of how precision works
+		// we cannot just subtract 1 because of how precision works
 		{float64(math.MinInt64 - 1024 - 1), false},
 
 		// WARNING : this is due to how floats are compared

validator/string.go

@@ -1,32 +1,37 @@
-package builtin
+package validator
 
 import (
 	"reflect"
 	"regexp"
 	"strconv"
-
-	"git.xdrm.io/go/aicra/datatype"
 )
 
-var fixedLengthRegex = regexp.MustCompile(`^string\((\d+)\)$`)
-var variableLengthRegex = regexp.MustCompile(`^string\((\d+), ?(\d+)\)$`)
+var (
+	fixedLengthRegex    = regexp.MustCompile(`^string\((\d+)\)$`)
+	variableLengthRegex = regexp.MustCompile(`^string\((\d+), ?(\d+)\)$`)
+)
 
-// StringDataType is what its name tells
-type StringDataType struct{}
+// StringType makes the types beloz available in the aicra configuration:
+// - "string" considers any string valid
+// - "string(n)" considers any string with an exact size of `n` valid
+// - "string(a,b)" considers any string with a size between `a` and `b` valid
+// > for the last one, `a` and `b` are included in the valid sizes
+type StringType struct{}
 
-// Type returns the type of data
-func (StringDataType) Type() reflect.Type {
+// GoType returns the `string` type
+func (StringType) GoType() reflect.Type {
 	return reflect.TypeOf(string(""))
 }
 
-// Build returns the validator.
-// availables type names are : `string`, `string(length)` and `string(minLength, maxLength)`.
-func (s StringDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
-	simple := typeName == "string"
-	fixedLengthMatches := fixedLengthRegex.FindStringSubmatch(typeName)
-	variableLengthMatches := variableLengthRegex.FindStringSubmatch(typeName)
+// Validator for strings with any/fixed/bound sizes
+func (s StringType) Validator(typename string, avail ...Type) ValidateFunc {
+	var (
+		simple                = (typename == "string")
+		fixedLengthMatches    = fixedLengthRegex.FindStringSubmatch(typename)
+		variableLengthMatches = variableLengthRegex.FindStringSubmatch(typename)
+	)
 
-	// nothing if type not handled
+	// ignore unknown typename
 	if !simple && fixedLengthMatches == nil && variableLengthMatches == nil {
 		return nil
 	}
@@ -40,7 +45,7 @@ func (s StringDataType) Build(typeName string, registry ...datatype.T) datatype.
 	if fixedLengthMatches != nil {
 		exLen, ok := s.getFixedLength(fixedLengthMatches)
 		if !ok {
-			mustFail = true
+			return nil
 		}
 		min = exLen
 		max = exLen
@@ -49,7 +54,7 @@ func (s StringDataType) Build(typeName string, registry ...datatype.T) datatype.
 	} else if variableLengthMatches != nil {
 		exMin, exMax, ok := s.getVariableLength(variableLengthMatches)
 		if !ok {
-			mustFail = true
+			return nil
 		}
 		min = exMin
 		max = exMax
@@ -84,7 +89,7 @@ func (s StringDataType) Build(typeName string, registry ...datatype.T) datatype.
 }
 
 // getFixedLength returns the fixed length from regex matches and a success state.
-func (StringDataType) getFixedLength(regexMatches []string) (int, bool) {
+func (StringType) getFixedLength(regexMatches []string) (int, bool) {
 	// incoherence error
 	if regexMatches == nil || len(regexMatches) < 2 {
 		return 0, false
@@ -100,7 +105,7 @@ func (StringDataType) getFixedLength(regexMatches []string) (int, bool) {
 }
 
 // getVariableLength returns the length min and max from regex matches and a success state.
-func (StringDataType) getVariableLength(regexMatches []string) (int, int, bool) {
+func (StringType) getVariableLength(regexMatches []string) (int, int, bool) {
 	// incoherence error
 	if regexMatches == nil || len(regexMatches) < 3 {
 		return 0, 0, false

validator/string_test.go

@@ -1,16 +1,29 @@
-package builtin_test
+package validator_test
 
 import (
 	"fmt"
+	"reflect"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
+func TestString_ReflectType(t *testing.T) {
+	t.Parallel()
+
+	var (
+		dt       = validator.StringType{}
+		expected = reflect.TypeOf(string("abc"))
+	)
+	if dt.GoType() != expected {
+		t.Fatalf("invalid GoType() %v ; expected %v", dt.GoType(), expected)
+	}
+}
+
 func TestString_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	dt := builtin.StringDataType{}
+	dt := validator.StringType{}
 
 	tests := []struct {
 		Type    string
@@ -53,7 +66,7 @@ func TestString_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			validator := dt.Build(test.Type)
+			validator := dt.Validator(test.Type)
 
 			if validator == nil {
 				if test.Handled {
@@ -75,7 +88,7 @@ func TestString_AnyLength(t *testing.T) {
 
 	const typeName = "string"
 
-	validator := builtin.StringDataType{}.Build(typeName)
+	validator := validator.StringType{}.Validator(typeName)
 	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()
@@ -133,7 +146,7 @@ func TestString_FixedLength(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			validator := builtin.StringDataType{}.Build(test.Type)
+			validator := validator.StringType{}.Validator(test.Type)
 			if validator == nil {
 				t.Errorf("expect %q to be handled", test.Type)
 				t.Fail()
@@ -194,7 +207,7 @@ func TestString_VariableLength(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
-			validator := builtin.StringDataType{}.Build(test.Type)
+			validator := validator.StringType{}.Validator(test.Type)
 			if validator == nil {
 				t.Errorf("expect %q to be handled", test.Type)
 				t.Fail()

validator/uint.go

@@ -1,25 +1,28 @@
-package builtin
+package validator
 
 import (
 	"encoding/json"
 	"math"
 	"reflect"
-
-	"git.xdrm.io/go/aicra/datatype"
 )
 
-// UintDataType is what its name tells
-type UintDataType struct{}
+// UintType makes the "uint" type available in the aicra configuration
+// It considers valid:
+// - uint
+// - int (since it does not overflow)
+// - float64 (since it does not overflow)
+// - strings containing json-compatible integers
+// - []byte containing json-compatible integers
+type UintType struct{}
 
-// Type returns the type of data
-func (UintDataType) Type() reflect.Type {
+// GoType returns the `uint` type
+func (UintType) GoType() reflect.Type {
 	return reflect.TypeOf(uint(0))
 }
 
-// Build returns the validator
-func (UintDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
-	// nothing if type not handled
-	if typeName != "uint" {
+// Validator for uint values
+func (UintType) Validator(other string, avail ...Type) ValidateFunc {
+	if other != "uint" {
 		return nil
 	}
 

validator/uint_test.go

@@ -1,17 +1,30 @@
-package builtin_test
+package validator_test
 
 import (
 	"fmt"
 	"math"
+	"reflect"
 	"testing"
 
-	"git.xdrm.io/go/aicra/datatype/builtin"
+	"github.com/xdrm-io/aicra/validator"
 )
 
+func TestUint_ReflectType(t *testing.T) {
+	t.Parallel()
+
+	var (
+		dt       = validator.UintType{}
+		expected = reflect.TypeOf(uint(0))
+	)
+	if dt.GoType() != expected {
+		t.Fatalf("invalid GoType() %v ; expected %v", dt.GoType(), expected)
+	}
+}
+
 func TestUint_AvailableTypes(t *testing.T) {
 	t.Parallel()
 
-	dt := builtin.UintDataType{}
+	dt := validator.UintType{}
 
 	tests := []struct {
 		Type    string
@@ -27,7 +40,7 @@ func TestUint_AvailableTypes(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.Type, func(t *testing.T) {
-			validator := dt.Build(test.Type)
+			validator := dt.Validator(test.Type)
 			if validator == nil {
 				if test.Handled {
 					t.Errorf("expect %q to be handled", test.Type)
@@ -50,7 +63,7 @@ func TestUint_Values(t *testing.T) {
 
 	const typeName = "uint"
 
-	validator := builtin.UintDataType{}.Build(typeName)
+	validator := validator.UintType{}.Validator(typeName)
 	if validator == nil {
 		t.Errorf("expect %q to be handled", typeName)
 		t.Fail()

validator/validator.go

@@ -0,0 +1,55 @@
+package validator
+
+import (
+	"reflect"
+)
+
+// ValidateFunc returns whether a given value fulfills the datatype and casts
+// the value into a go type.
+//
+// for example, if a validator checks for upper case strings, whether the value
+// is a []byte, a string or a []rune, if the value matches is all upper-case, it
+// will be cast into a go type, say, string.
+type ValidateFunc func(value interface{}) (cast interface{}, valid bool)
+
+// Type defines an available in/out parameter "type" for the aicra configuration
+//
+// A Type maps to a go type in order to generate the handler signature from the
+// aicra configuration
+//
+// A Type returns a custom validator when the typename matches
+type Type interface {
+	// Validator function when the typename matches. It must return nil when the
+	// typename does not match
+	//
+	// The `typename` argument has to match types used in your aicra configuration
+	// in parameter definitions ("in", "out") and in the "type" json field.
+	//
+	// basic example:
+	// - `IntType.Validator("string")`` should return nil
+	// - `IntType.Validator("int")`` should return its ValidateFunc
+	//
+	// The `typename` is not returned by a simple method i.e. `TypeName() string`
+	// because it allows for validation relative to the typename, for instance:
+	// - `VarcharType.Validator("varchar")` valides any string
+	// - `VarcharType.Validator("varchar(2)")` validates any string of 2
+	//   characters
+	// - `VarcharType.Validator("varchar(1,3)")` validates any string
+	//   with a length between 1 and 3
+	//
+	// The `avail` argument represents all other available Types. It allows a
+	// Type to use other available Types internally.
+	//
+	// recursive example: slices
+	// - `SliceType.Validator("[]int", avail...)` validates a slice containing
+	//   values that are valide to the `IntType`
+	// - `SliceType.Validator("[]varchar", avail...)` validates a slice containing
+	//   values that are valid to the `VarcharType`
+	//
+	// and so on.. this works for maps, structs, etc
+	Validator(typename string, avail ...Type) ValidateFunc
+
+	// GoType must return the go type associated with the output type of ValidateFunc.
+	// It is used to define handlers' signature from the configuration file.
+	GoType() reflect.Type
+}