517 lines
22 KiB
Markdown
517 lines
22 KiB
Markdown
# | aicra |
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[![Go version](https://img.shields.io/badge/go_version-1.10.3-blue.svg)](https://golang.org/doc/go1.10)
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[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
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[![Go Report Card](https://goreportcard.com/badge/git.xdrm.io/go/aicra)](https://goreportcard.com/report/git.xdrm.io/go/aicra)
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[![Go doc](https://godoc.org/git.xdrm.io/go/aicra?status.svg)](https://godoc.org/git.xdrm.io/go/aicra)
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**Aicra** is a *configuration-driven* REST **API engine** in *Go* that allows you to create a fully featured API.
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The whole API management is done for you from a configuration file describing your API, you just need to implement :
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- the <u>controllers</u>
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- the <u>middle-wares</u> (_e.g. authentication, csrf_)
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- and optionnally the <u>type checkers</u> to check if input values follows some rules
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> There is 2 available drivers that will load your implementations. The `plugin` driver is for Go programmers, the `generic` one is for any language (it uses standard input and output).
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The engine has been designed with the following concepts in mind.
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| concept | explanation |
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|---|---|
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| meaningful defaults | Defaults and default values work without further understanding |
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| configuration driven | Avoid information duplication. Automate anything that can be automated without losing control. Have *one* configuration that summarizes the whole API, its behavior and its automation flow. |
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> A example project is available [here](https://git.xdrm.io/example/aicra)
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### Table of contents
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<!-- toc -->
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* [I. Installation](#i-installation)
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* [1. Download and install the package](#1-download-and-install-the-package)
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* [II. Setup a project](#ii-setup-a-project)
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* [1. Compilation configuration](#1-compilation-configuration)
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* [Example](#example)
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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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* [3. Example](#3-example)
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* [3. Controllers](#3-controllers)
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* [1. Plugin driver](#1-plugin-driver)
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* [2. Generic driver](#2-generic-driver)
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* [4. Middle-wares](#4-middle-wares)
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* [1. Plugin driver](#1-plugin-driver-1)
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* [2. Generic driver](#2-generic-driver-1)
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* [5. Type checkers](#5-type-checkers)
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* [1. Plugin driver](#1-plugin-driver-2)
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* [2. Generic driver](#2-generic-driver-2)
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* [III. Build your project](#iii-build-your-project)
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* [IV. Main](#iv-main)
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* [V. Change Log](#v-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).
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> This package has not been tested under the version **1.10**.
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#### 1. Download and install the package
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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 locally as `git.xdrm.io/go/aicra` your imports. Moreover, the **project compiler** have been installed as the `aicra` command.
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> The executable `aicra` will be placed into your `$GOPATH/bin` folder, if added to your environment PATH it should be available as a standalone command in your terminal. If not, you can simply run `$GOPATH/bin/aicra` to use the command or create a symbolic link into `/usr/local/bin` for instance.
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### II. Setup a project
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The default project structure is :
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```bash
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├── main.go # entry point
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├── aicra.json # server configuration file
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├── api.json # API configuration file
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├── middleware # middleware implementations
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├── controller # controller implementations
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└── type # custom type checkers
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```
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#### 1. Compilation configuration
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The `aicra.json` configuration file defines where are located your controllers, type checkers, and middle-wares ; also it contains what driver you want to use, you have 2 choices :
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1. **plugin** - for Go implementations (_c.f. [go plugin system](https://golang.org/pkg/plugin/)_)
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2. **generic** - for any language implementation (uses standard input and output)
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The file uses the [json](https://json.org/) format, each field is described in the table above.
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| field | description | example value |
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| ---------------------- | ------------------------------------------------------------ | --------------------------------- |
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| `root` | The project folder path | `./some-path` or `/some/path` |
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| `driver` | The driver to use for loading controllers, middlewares and type checkers | `plugin` or `generic` |
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| `types`.`default` | Whether to load default types into the project | `true` or `false` |
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| `types`.`folder` | The folder (relative to the project root) where type checkers' implementations are located | `./type` or `type` |
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| `controllers`.`folder` | The folder (relative to the project root) where controllers' implementations are located | `./controller` or `controller` |
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| `middlewares`.`folder` | The folder (relative to the project root) where middlewares' implementations are located | `./middleware` or `middleware` |
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A sample file can be found [here](https://git.xdrm.io/example/aicra/src/master/aicra.json).
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###### Example
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In this example we have the controllers inside the `controller` folder, the middle-wares in the `middleware` folder and custom type checkers inside the `checker` folder, we want to load the built-in type checkers and are using the `plugin` driver. Also our project root is the relative current path `.` ; note that it is better using an absolute path as your project root.
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```json
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{
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"root": ".",
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"driver": "plugin",
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"types": {
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"default": true,
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"folder": "checker"
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},
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"controllers": {
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"folder": "controller.plugin"
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},
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"middlewares": {
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"folder": "middleware.plugin"
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}
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}
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```
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#### 2. API Configuration
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The whole project behavior is described inside the `api.json` file. For a better understanding of the format, take a look at this working [template](https://git.xdrm.io/example/aicra/src/master/api.json). This file defines :
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- resource 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 for clients to use which method)
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- input policy :
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- type of argument (_i.e. for type checkers_)
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- required/optional
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- default value
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- variable renaming
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###### Definition
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At the root of the json file are available 5 field names :
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1. `GET` - to define what to do when receiving a request with a GET HTTP method at the root URI
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2. `POST` - to define what to do when receiving a request with a POST HTTP method at the root URI
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3. `PUT` - to define what to do when receiving a request with a PUT HTTP method at the root URI
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4. `DELETE` - to define what to do when receiving a request with a DELETE HTTP method at the root URI
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5. `/` - to define children URIs ; each will have the same available fields
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For each method 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. See [here](#input-arguments) for details. | |
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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 is only use for readability purpose and documentation. | |
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##### Input Arguments
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###### 1. Input types
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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** - Slash-separated strings right after the resource URI. For instance, if your controller is bound to the `/user` URI, you can use the *URI slot* right after to send the user ID ; Now a client can send requests to the URI `/user/:id` where `:id` is a number sent by the client. This kind of input cannot be extracted by name, but rather by index in the URL (_begins at 0_).
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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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###### 2. Global 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 must be <u>prefixed</u> when requesting **URI** or **Query** input types.
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>
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> - The first **URI** data has to be named `URL#0`, the second one `URL#1` and so on...
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> - The variable named `somevar` in the **Query** has to be named `GET@somvar` in the configuration.
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**Example**
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In this example we want 3 arguments :
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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 (else the controller will not be run). It is renamed `uri-param`, this new name will be sent to the controller.
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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 `int` or not given at all (the `?` at the beginning of the type tells that the argument is **optional**) ; it will be named `get-param`.
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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 controller with the name `multipart-var`.
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```json
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"in": {
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// arg 1
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"URL#0": {
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"info": "some integer in the URI",
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"type": "int",
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"name": "uri-param"
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},
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// arg 2
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"GET@get-var": {
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"info": "some Query OPTIONAL variable",
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"type": "?int",
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"name": "get-param"
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},
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// arg 3
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"multipart-var": { /* ... */ }
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}
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```
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###### 3. Example
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In this example you can see a pretty basic user/article REST API definition. The API let's you fetch, create, edit, and delete users and do the same for their articles. Users actions will be available at the uri `/user`, and `/article` for articles.
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#### 3. Controllers
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Controllers implement `Get`, `Post`, `Put`, and `Delete` methods, and have access to special variables injected in the argument list :
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- `_HTTP_METHOD_` the request's HTTP method in uppercase
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- `_SCOPE_` the scope filled by middle-wares
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- `_AUTHORIZATION_` the request's **Authorization** header
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Also special variables found in the return data are processed with special actions :
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- `_REDIRECT_` will redirect to the URL contained in the variable
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##### 1. Plugin driver
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For each route, you'll have to place your implementation into the `controller` folder (according to the *aicra.json* configuration) following the naming convention : add `/main.go` at the end of the route.
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> <u>Example</u> - the URI `/path/to/some/uri` is handled by the file `controller/path/to/some/uri/main.go`
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>
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> <u>Exception</u> - the URI `/` is handled by the file `controller/ROOT/main.go`
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A sample directory structure is available [here](https://git.xdrm.io/example/aicra/src/master/controller.plugin).
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Each controller must implement the [driver.Controller](https://godoc.org/git.xdrm.io/go/aicra/driver#Controller) interface. In addition you must declare the function `func Export() Controller` to allow dynamic loading of your controller.
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**Example**
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Here is a base code for any controllers
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```go
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package main
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import (
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"git.xdrm.io/go/aicra/driver"
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"git.xdrm.io/go/aicra/api"
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e "git.xdrm.io/go/aicra/err"
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)
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// Mockup controller implementation
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type MyController interface{}
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func Export() driver.Controller { return new(MyController) }
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// GET method management
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func (c MyController) Get(args api.Arguments) api.Response {
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res := api.NewResponse()
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res.Err = e.Success
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return *res
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}
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// POST method management
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func (c MyController) Post(args api.Arguments) api.Response { /*...*/ }
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// PUT method management
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func (c MyController) Put(args api.Arguments) api.Response { /*...*/ }
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// DELETE method management
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func (c MyController) Delete(args api.Arguments) api.Response { /*...*/ }
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```
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##### 2. Generic driver
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This is the same as with the plugin driver but without `/main.go` at the end.
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> <u>Example</u> - The URI `/path/to/some/uri` will be handled by the executable `controller/path/to/some/uri`.
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> <u>Exception</u> - The URI `/` will be handled by the executable `controller/ROOT`.
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A sample directory structure is available [here](https://git.xdrm.io/example/aicra/src/master/controller.generic).
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The programs will be given useful data (*i.e. method and arguments*) through its input arguments :
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| Argument index | Description | Examble value |
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| -------------- | ------------------------------------------------------------ | ------------------------------------------------------------ |
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| 1 | Uppercase HTTP method.<br>(_e.g. **$1** in bash, **argv[1]** in php_) | `GET`, `POST`, ... |
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| 2 | JSON representation of the input arguments.<br>(_e.g. **$2** in bash, **argv[2]** in php_) | `{`<br> `"_SCOPE_": ["admin", "token"],`<br> `"somstring": "string",`<br> `"someint": 12`<br>`}` |
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The standard output you will give back must be a key-value JSON representation of all the output variables.
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#### 4. Middle-wares
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In order for your project to manage authentication, the best solution is to use middle-wares, there are programs that updates a *Scope* (*i.e. a list of strings*) according to internal or persistent (*i.e.* database) information and the actual http request. They are all run before each request is forwarded to your controller. The Scopes are used to match the `scope` field in the configuration file and automatically block access to non-authenticated method calls. Scopes can also be used for implementation-specific behavior such as _CSRF_ management. Controllers have access to the scope through the variable `_SCOPE_`.
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##### 1. Plugin driver
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Each middleware must be **directly** inside the `middleware` folder (according to the _aicra.json_ configuration).
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> Example - the `1-authentication` middleware will be inside `middleware/1-authentication/main.go`.
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**Note** - middle-ware execution will be ordered by name. Prefixing your middle-wares with their order is a good practice.
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A sample directory structure is available [here](https://git.xdrm.io/example/aicra/src/master/middleware.plugin).
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Each middle-ware must implement the [driver.Middleware](https://godoc.org/git.xdrm.io/go/aicra/driver#Middleware) interface. In addition you must declare the function `func Export() Middleware` to allow dynamic loading of your middle-ware.
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**Example**
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Here is a base code for any middle-ware
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```go
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package main
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import (
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"git.xdrm.io/go/aicra/driver"
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"net/http"
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)
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// Mockup middle-ware implementation
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type MyMiddleware interface{}
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func Export() driver.Middleware { return new(MyMiddleware) }
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func (c MyMiddleware) Inspect(req http.Request, scope *[]string) {
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// add scope according to request
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if req.Header.Get("SomeHeader") {
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*scope = append(*scope, "some-scope")
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}
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}
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```
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##### 2. Generic driver
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This is the same as with the plugin driver but instead of without `/main.go` at the end.
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> Example - the `1-authentication` middle-ware will be inside `middleware/1-authentication` where **1-authentication** is an executable
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A sample directory structure is available [here](https://git.xdrm.io/example/aicra/src/master/middleware.generic).
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The programs will be given useful data (*i.e. method and arguments*) through its input arguments :
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| Argument index | Description | Examble value |
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| -------------- | ------------------------------------------------------------ | ------------- |
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| 1 | JSON representation of the input arguments.<br>(_e.g. **$1** in bash, **argv[1]** in php_) | ??? |
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The standard output you will give back must be a JSON array containing the scope you want to add.
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#### 5. Type checkers
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In your configuration you can use built-in types (*e.g.* int, any, varchar, token, float, ...), but if you want project-specific ones, you can add your own types inside the `type` folder. You can check what structure to follow by looking at the [built-in types](https://git.xdrm.io/go/aicra/src/master/internal/checker/default). Also it is not required that you use built-in types, you can ignore them by setting `types.default = false` in the _aicra.json_ configuration.
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Each type must be **directly** inside the `type` folder. The package name is arbitrary and does not have to match the name (but it is better if it is explicit), because the `Match()` method already does that.
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##### 1. Plugin driver
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Each type checker must be **directly** inside the `type` folder (according to the _aicra.json_ configuration).
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> Example - the `number` type checker will be inside `type/number/main.go`.
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A sample directory structure is available [here](https://git.xdrm.io/example/aicra/src/master/type.plugin).
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##### 2. Generic driver
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This is the same as with the plugin driver but instead of without `/main.go` at the end.
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> Example - the `number` type checker will be inside `type/number` where **number** is an executable
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A sample directory structure is available [here](https://git.xdrm.io/example/aicra/src/master/type.generic).
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The programs will be given useful data (*i.e. method and arguments*) through its input arguments :
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| Argument index | Description | Examble value |
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| -------------- | ------------------------------------------------------------ | ------------------ |
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| 1 | Uppercase method.<br>(_e.g. **$1** in bash, **argv[1]** in php_) | `MATCH` or `CHECK` |
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| 2 | JSON representation of the input arguments.<br>(_e.g. **$2** in bash, **argv[2]** in php_) | ??? |
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The standard output you will give back must be a `1` or `0` representing `true` and `false`.
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+ When calling the `MATCH` method, the input argument consists of a string being the type checker name, you must return `1` this name is handled by the current type checker.
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+ When calling the `CHECK` method, the input argument consists of a JSON representation wrapped inside the key `value`. For instance it could be `{"value": [1,2,3]}` if the input value is an array containing 1, 2, and 3.
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### III. Build your project
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After each controller, middle-ware or type checker implementation, you'll have to compile the project. This can be achieved through the command-line builder.
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Usage is `aicra /path/to/your/project`.
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Usually you just have to run the following command inside your project directory :
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```bash
|
||
aicra .
|
||
```
|
||
|
||
The output should look like
|
||
|
||
![that](./README.assets/1531039386654.png).
|
||
|
||
#### IV. Main
|
||
|
||
The main default program is pretty small as shown below :
|
||
|
||
```go
|
||
package main
|
||
|
||
import (
|
||
"git.xdrm.io/go/aicra"
|
||
"net/http"
|
||
)
|
||
|
||
func main() {
|
||
|
||
// build from config
|
||
server, err := aicra.New("api.json")
|
||
if err != nil { panic(err) }
|
||
|
||
// launch server
|
||
err = http.ListenAndServe("127.0.0.1:4242", server)
|
||
if err != nil { panic(err) }
|
||
|
||
}
|
||
```
|
||
|
||
|
||
|
||
|
||
#### V. Change Log
|
||
|
||
- [x] human-readable json configuration
|
||
- [x] nested routes (*i.e. `/user/:id:` and `/user/post/:id:`*)
|
||
- [ ] nested URL arguments (*i.e. `/user/:id:` and `/user/:id:/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
|
||
- [x] required vs. optional parameters with a default value
|
||
- [x] parameter renaming
|
||
- [ ] ~~generic authentication system (*i.e. you can override the built-in one*)~~ Replaced by the middle-ware system
|
||
- [x] generic type check (*i.e. implement custom types alongside built-in ones*)
|
||
- [ ] built-in types
|
||
- [x] `any` - wildcard matching all values
|
||
- [x] `int` - any number (*e.g. float, int, uint*)
|
||
- [x] `string` - any text
|
||
- [x] `varchar(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] response interface
|
||
- [ ] ~~devmode watcher~~ : watch manifest, watch plugins to compile + hot reload them
|
||
- [x] driver for Go plugins
|
||
- [x] controllers
|
||
- [x] middlewares
|
||
- [x] type checkers
|
||
- [x] driver working with any executable through standard input and output
|
||
- [x] controllers
|
||
- [x] middlewares
|
||
- [x] type checkers
|
||
- [x] project configuration file to select **driver**, source folders and whether to load default type checkers.
|
||
- [x] used to compile the project by the `aicra` command
|
||
- [x] used to create an API from `aicra.New()`
|