197 lines
7.4 KiB
Markdown
197 lines
7.4 KiB
Markdown
# | aicra |
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[](https://golang.org/doc/go1.10)
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[](https://opensource.org/licenses/MIT)
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[](https://goreportcard.com/report/git.xdrm.io/go/aicra)
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[](https://godoc.org/git.xdrm.io/go/aicra)
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[](https://drone.xdrm.io/go/aicra)
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Aicra is a *configuration-driven* REST API engine written in Go.
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Most of the management is done for you using a configuration file describing your API. you're left with implementing :
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- handlers
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- optionnally middle-wares (_e.g. authentication, csrf_)
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- and optionnally your custom type checkers to check input parameters
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> A example project is available [here](https://git.xdrm.io/go/articles-api)
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## Table of contents
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<!-- toc -->
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- [I/ Installation](#i-installation)
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- [II/ Usage](#ii-usage)
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* [1) Build a server](#1-build-a-server)
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* [2) API Configuration](#2-api-configuration)
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- [Definition](#definition)
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+ [Input Arguments](#input-arguments)
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- [1. Input types](#1-input-types)
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- [2. Global Format](#2-global-format)
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- [III/ Change Log](#iii-change-log)
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<!-- tocstop -->
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## I/ Installation
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You need a recent machine with `go` [installed](https://golang.org/doc/install). This package has not been tested under the version **1.14**.
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```bash
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go get -u git.xdrm.io/go/aicra/cmd/aicra
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```
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The library should now be available as `git.xdrm.io/go/aicra` in your imports.
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## II/ Usage
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### 1) Build a server
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Here is some sample code that builds and sets up an aicra server using your api configuration file.
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```go
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package main
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import (
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"log"
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"net/http"
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"os"
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"git.xdrm.io/go/aicra"
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"git.xdrm.io/go/aicra/api"
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"git.xdrm.io/go/aicra/datatype/builtin"
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)
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func main() {
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builder := &aicra.Builder{}
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// add datatypes your api uses
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builder.AddType(builtin.BoolDataType{})
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builder.AddType(builtin.UintDataType{})
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builder.AddType(builtin.StringDataType{})
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config, err := os.Open("./api.json")
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if err != nil {
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log.Fatalf("cannot open config: %s", err)
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}
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// pass your configuration
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err = builder.Setup(config)
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config.Close()
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if err != nil {
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log.Fatalf("invalid config: %s", err)
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}
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// bind your handlers
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builder.Bind(http.MethodGet, "/user/{id}", getUserById)
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builder.Bind(http.MethodGet, "/user/{id}/username", getUsernameByID)
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// build the server and start listening
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server, err := builder.Build()
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if err != nil {
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log.Fatalf("cannot build server: %s", err)
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}
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http.ListenAndServe("localhost:8080", server)
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}
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```
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Here is an example handler
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```go
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type req struct{
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Param1 int
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Param3 *string // optional are pointers
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}
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type res struct{
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Output1 string
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Output2 bool
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}
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func myHandler(r req) (*res, api.Error) {
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err := doSomething()
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if err != nil {
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return nil, api.ErrorFailure
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}
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return &res{}, api.ErrorSuccess
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}
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```
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### 2) API Configuration
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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 [template](https://git.xdrm.io/go/articles-api/src/master/api.json). This file defines :
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- routes and their methods
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- every input for each method (called *argument*)
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- every output for each method
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- scope permissions (list of permissions needed by clients)
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- input policy :
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- type of argument (_c.f. data types_)
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- required/optional
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- variable renaming
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#### Format
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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.
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| field path | description | example |
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| ---------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
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| `info` | A short human-readable description of what the method does | `create a new user` |
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| `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) |
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| `in` | The list of arguments that the clients will have to provide. [Read more](#input-arguments). | |
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| `out` | The list of output data that will be returned by your controllers. It has the same syntax as the `in` field but optional parameters are not allowed |
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### Input Arguments
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Input arguments defines what data from the HTTP request the method needs. Aicra is able to extract 3 types of data :
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- **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.
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- **Query** - data formatted at the end of the URL following the standard [HTTP Query](https://tools.ietf.org/html/rfc3986#section-3.4) syntax.
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- **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.
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- **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.
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- **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.
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#### Format
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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.
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> Variable names from **URI** or **Query** must be named accordingly :
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>
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> - the **URI** variable `{id}` from your request route must be named `{id}`.
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> - the variable `somevar` in the **Query** has to be names `GET@somevar`.
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**Example**
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In this example we want 3 arguments :
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```json
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[
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{
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"method": "PUT",
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"path": "/article/{id}",
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"scope": [["author"]],
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"info": "updates an article",
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"in": {
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"{id}": { "info": "article id", "type": "int", "name": "article_id" },
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"GET@title": { "info": "new article title", "type": "?string", "name": "title" },
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"content": { "info": "new article content", "type": "string" }
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},
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"out": {
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"id": { "info": "updated article id", "type": "uint" },
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"title": { "info": "updated article title", "type": "string" },
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"content": { "info": "updated article content", "type": "string" }
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}
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}
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]
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```
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- 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.
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- 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`.
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- 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`.
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