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# | aicra |
<p align="center">
<a href="https://git.xdrm.io/go/aicra">
<img src="https://git.xdrm.io/go/aicra/raw/branch/feature/improve-readme/readme.assets/logo.png" alt="aicra logo" width="200" height="200">
</a>
</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)
<h3 align="center">aicra</h3>
----
<p align="center">
Fast, intuitive, and powerful configuration-driven engine for faster and easier <em>REST</em> development.
</p>
`aicra` is a lightweight and idiomatic API engine for building Go services. It's especially good at helping you write large REST API services that remain maintainable as your project grows.
[![Go version](https://img.shields.io/badge/go_version-1.16-blue.svg)](https://golang.org/doc/go1.16) [![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)
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 configuration file to drive the server. The configuration format describes the whole API: routes, input arguments, expected output, permissions, etc.
## Presentation
TL;DR: `aicra` is a fast configuration-driven REST API engine.
`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.
Repetitive tasks is automatically processed by `aicra` from your configuration file, you just have to implement your handlers.
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.
The engine automates :
- catching input data (_url, query, form-data, json, url-encoded_)
- handling missing input data (_required arguments_)
- handling input data validation
- checking for mandatory output parameters
- checking for missing method implementations
- checking for handler signature (input and output arguments)
Repetitive tasks are automatically processed by `aicra` based on your configuration, you're left with implementing your handlers (_usually business logic_).
> An example project is available [here](https://git.xdrm.io/go/articles-api)
### Table of contents
## Table of contents
<!-- toc -->
* [Installation](#installation)
- [Usage](#usage)
- [Create a server](#create-a-server)
- [Create a handler](#create-a-handler)
- [Configuration](#configuration)
- [Global format](#global-format)
* [Input section](#input-section)
+ [Format](#format)
- [Example](#example)
- [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 -->
## Installation
You need a recent machine with `go` [installed](https://golang.org/doc/install). The package has not been tested under **go1.14**.
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
$ go get -u git.xdrm.io/go/aicra
```
2. Import it in your code:
```go
import "git.xdrm.io/go/aicra"
```
## What's automated
# Usage
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.
Http requests are only accepted when they have the permissions you have defined. If unauthorized, the request is rejected with an error response.
#### Create a server
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.
The code below sets up and creates an HTTP server from the `api.json` configuration.
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
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
@ -76,13 +91,13 @@ import (
func main() {
builder := &aicra.Builder{}
// register available validators
// register data validators
builder.AddType(builtin.BoolDataType{})
builder.AddType(builtin.UintDataType{})
builder.AddType(builtin.StringDataType{})
// load your configuration
config, err := os.Open("./api.json")
config, err := os.Open("api.json")
if err != nil {
log.Fatalf("cannot open config: %s", err)
}
@ -92,11 +107,14 @@ func main() {
log.Fatalf("invalid config: %s", err)
}
// bind your handlers
builder.Bind(http.MethodGet, "/user/{id}", getUserById)
builder.Bind(http.MethodGet, "/user/{id}/username", getUsernameByID)
// bind handlers
err = builder.Bind(http.MethodGet, "/user/{id}", getUserById)
if err != nil {
log.Fatalf("cannog bind GET /user/{id}: %s", err)
}
// ...
// build the handler and start listening
// build your services
handler, err := builder.Build()
if err != nil {
log.Fatalf("cannot build handler: %s", err)
@ -106,22 +124,123 @@ func main() {
```
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{},
// aicra handler
Handler: handler,
// ...
Handler: AICRAHandler,
}
server.ListenAndServe()
}
```
## Configuration file
#### Create a handler
First of all, the configuration uses `json`.
> Quick note if you thought: "I have JSON, I would have preferred yaml, or even xml !"
>
> 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.
Let's take a quick look at the configuration format !
> 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)
### 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": "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`.
## 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
@ -151,9 +270,9 @@ func myHandler(r req) (*res, api.Err) {
}
```
If your handler signature does not match the configuration exactly, the server will print out the error and will not start.
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; client will then always have to manage the same format.
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": {
@ -163,83 +282,7 @@ The `api.Err` type automatically maps to HTTP status codes and error description
}
```
# Configuration
The whole api 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 [configuration](https://git.xdrm.io/go/articles-api/src/master/api.json).
The configuration file defines :
- routes and their methods
- every input argument for each method
- every output for each method
- scope permissions (list of permissions required by clients)
- input policy :
- type of argument (_c.f. data types_)
- required/optional
- variable renaming
#### Global format
The root of the json file must feature an array containing your requests definitions. For each, you will have to create fields described in the table above.
- `info`: Short description of the method
- `in`: List of arguments that the clients will have to provide. [Read more](#input-arguments).
- `out`: List of output data that your controllers will output. It has the same syntax as the `in` field but optional parameters are not allowed.
- `scope`: A 2-dimensional array of permissions. The first level means **or**, the second means **and**. It allows to combine permissions in complex ways.
- Example: `[["A", "B"], ["C", "D"]]` translates to : this method requires users to have permissions (A **and** B) **or** (C **and** D)
##### Input section
Input arguments defines what data from the HTTP request the method requires. `aicra` is able to extract 3 types of data :
- **URI** - data from 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 at the end of the URL following the standard [HTTP Query](https://tools.ietf.org/html/rfc3986#section-3.4) syntax.
- **Form** - data send from the body of the request ; it can be extracted in 3 ways:
- _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 send in the body as a json object ; each key being a variable name, each value its content. Note that the 'Content-Type' header must be set to `application/json` for the API to use it.
> For Form data, the 3 methods can be used at once for different arguments; for instance if you need to send a file to an aicra server as well as other parameters, you can use JSON for parameters and Multipart for the file.
###### Format
The `in` field describes 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 :
- an **URI** variable `{var}` from your request route must be named `{var}` in the `in` section
- a variable `var` in the **Query** has to be named `GET@var` in the `in` section
#### 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`.
# Changelog
## Changelog
- [x] human-readable json configuration
- [x] nested routes (*i.e. `/user/{id}` and `/user/post/{id}`*)

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