Yii2 Restful API 原理分析

Yii2 有个很重要的特性是对 Restful API的默认支持， 通过短短的几个配置就可以实现简单的对现有Model的RESTful API

参考另一篇文章： http://www.cnblogs.com/ganiks/p/yii2-restful-api-dev.html

本文通过分析rest部分源码，简单剖析下yii2 实现 restful 的原理，并通过一些定制实现 对 关联模型的RESTful api 操作。

原创文章， 转载请注明 http://www.cnblogs.com/ganiks/

~ 代表 extends from 的关系

| | rest/

| | |-Action.php ~ `\yii\base\Action`
| | |-Controller.php ~  `\yii\web\Controller`
| | | |-ActiveController.php ~ `rest\Controller`

| | |-Serializer.php ~ `yii\base\Component`
| | |-UrlRule.php ~ `yii\web\CompositeUrlRule`

| | |-CreateAction.php ~ `rest\Action`
| | |-DeleteAction.php ~ `rest\Action`
| | |-IndexAction.php ~ `rest\Action`
| | |-OptionsAction.php ~ `rest\Action`
| | |-UpdateAction.php ~ `rest\Action`
| | |-ViewAction.php ~ `rest\Action`

1. rest/Controller ~ \yii\web\Controller

---

Controller是 RESTful API 控制器类的基类

它在一个API请求的控制周期中一次实现了下面的步骤 1~5：

1. 解析响应的内容格式
2. 校验请求方法
3. 检验用户权限
4. 限制速度
5. 格式化响应数据

use yii\filters\auth\CompositeAuth;
use yii\filters\ContentNegotiator;
use yii\filters\RateLimiter;
use yii\web\Response;
use yii\filters\VerbFilter;
/**
 * Controller is the base class for RESTful API controller classes.
 *
 * Controller implements the following steps in a RESTful API request handling cycle
 * 1. Resolving response format (see [[ContentNegotiator]]);
 * 2. Validating request method (see [[verbs()]]).
 * 3. Authenticating user (see [[\yii\filters\auth\AuthInterface]]);
 * 4. Rate limiting (see [[RateLimiter]]);
 * 5. Formatting response data (see [[serializeData()]])

• behaviors
  • contentNegotiator
  • verbFilter
  • authenticator
  • rateLimiter
• afterAction
  • serializeData Yii::createObject($this->serializer)->serialize($data)
• verbs []

class Controller extends \yii\web\Controller
{
    public $serializer = 'yii\rest\Serializer';
    public $enableCsrfValidation = false;
    public function behaviors()
    {
        return [
            'contentNegotiator' => [
                'class' => ContentNegotiator::className(),
                'formats' => [
                    'application/json' => Response::FORMAT_JSON,
                    'application/xml' => Response::FORMAT_XML,
                ],
            ],
            'verbFilter' => [
                'class' => VerbFilter::className(),
                'actions' => $this->verbs(),
            ],
            'authenticator' => [
                'class' => CompositeAuth::className(),
            ],
            'rateLimiter' => [
                'class' => RateLimiter::className(),
            ],
        ]
    }
    public function verbs()
    {
        return [];
    }
    public function serializeData($data)
    {
        return Yii::createObject($this->serializer)->serialize($data);
    }
    public function afterAction($action, $result)
    {
        $result = parent::afterAction($action, $result);
        return $this->serializeData($result);
    }
}

1. rest/ActiveController ~ rest/Controller

---

ActiveController 实现了一系列的和 ActiveRecord 互通数据的RESTful方法

ActiveRecord 的类名由 modelClass 变量指明， yii\db\ActiveRecordInterface ???

默认的， 支持下面的方法：

 * - `index`: list of models
 * - `view`: return the details of a model
 * - `create`: create a new model
 * - `update`: update an existing model
 * - `delete`: delete an existing model
 * - `options`: return the allowed HTTP methods

可以通过覆盖 actions() 并且 unsetting 响应的 action 来禁用这些默认的动作。

要增加一个新的动作， 覆盖 actions() 向其末尾增加一个新的 action class 或者 是一个新的 action method

注意一点，确保你同时也覆盖了 verbs() 方法来声明这个新的动作支持那些HTTP Method

也需要覆盖checkAccess() 来检查当前用户是否有权限来执行响应的某个动作。

根据上面的说明再写一遍 Controller

class ActiveController extends Controller
{
    public #modelClass;
    public $updateScenario = Model::SCENARIO_DEFAULT;
    public $createScenario = Model::SCENARIO_DEFAULT;
    public function init()
    {
        parent::init();
        if($this->modelClass == null){
            throw new InvalidConfigException('The "modelClass" property must be set.');
        }
    }

    public function actions()
    {
        return [
            'index' => [
                'class' => 'app\controllers\rest\IndexAction',
                'modelClass' => $this->modelClass,
                'checkAccess' => [$this, 'checkAccess'],
            ],
            'view'...
            'create'...
            'update'...
            'delete'...
            'options'...
        ];
    }

    protected function verbs()
    {
        return [
            'index' => ['GET', 'HEAD'],
            'view' =>['GET', 'HEAD'],
            'create' =>['POST'],
            'update' =>['PUT', 'PATCH'],
            'delete' =>['DELETE'],
        ];
    }

    public function checkAccess($action, $model=null, $params = [])
    {
    }
}

下面来实现一个继承自 这个rest\ActiveController的 News 控制器：

namespace app\controllers;
use app\controllers\rest\ActiveController; #刚才这个AC，我从yii/rest下面拷贝了一份出来
class NewsController extends ActiveController
{
    public $modelClass ='app\models\News';
}

定义到这里就足够实现 rest\ActiveController 里面的默认方法了

下面来覆盖下，实现一些定制的方法

class NewsController extends ActiveController
{
    public $modelClass = 'app\models\News';
    #定制serializer
    #public $serializer = 'yii\rest\Serializer';
    public $serializer = [
        'class' => 'app\controllers\rest\Serializer',
        'collectionEnvelope' => 'items',
    ];
    public function behaviors()
    {
        $be = ArrayHelper::merge(
            parent::behaviors(),
            [
                'verbFilter' => [
                    'class' => VerbFilter::className(),
                    'actions' => [
                        'index' => ['get'],
                        ...
                    ]
                ],
                'authenticator' => [
                    'class' => CompositeAuth::className(),
                    'authMethods' => [
                        HttpBasicAuth::className(),
                        HttpBearerAuth::className(),
                        QueryParamAuth::className(),
                    ]
                ],
                'contentNegotiator' => [
                    'class' => ContentNegotiator::className(),
                    'formats' => [
                        'text/html' => Response::FORMAT_HTML,
                    ]
                ],
                'access' => [
				    'class' => AccessControl::className(),
				    'only' => ['view'],
				    'rules' => [
					    [
						    'actions' => ['view'],
						    'allow' => false,
						    'roles' => ['@'],
					    ],
				    ],
			    ]
            ],
        );
        return $be;
    }
    public function checkAccess()
    {
    }
}

1. 定制Actions

---

如果要对 Actions 进行大的改动，建议拷贝一份出来，不要使用原始的 yii\rest\XXXAction命名空间

我这里以要实现对related models进行 CURD 操作为目标进行大的改动

Action

在定制各个action之前， 先看看它们的基类 rest\Action, 主要是一个 findModel的方法

class Action extend \yii\base\Action
{
    public $modelClass;
    public $findModel;
    public $checkAccess;
    public function init()
    {
        if($this->modelClass == null) {
            throw new InvalidConfigException(get_class($this). '::$modelClass must be set');
        }
    }
    public function findModel($id)
    {
        if($this->findModel !== null) {
            return call_user_func($this->findModel, $id, $this);
        }
        $modelClass = $this->modelClass;
        $keys = $modelClass::primaryKey();
        if(count($keys) > 1) {
            $values = explode(',', $id);
            if..
        } elseif($id !== null) {
            $model = $modelClass::findOne($id);
        }

        if(isset($model)){
            return $model;
        }else {
            throw new NotFoundHttpException("Object not found: $id");
        }
    }
}

view

view 动作不需要改动，因为 model 有 getRelated 的自有机制

class ViewAction extend Action
{
    public function run($id)
    {
        $model = $this->findModel($id);
        if($this->checkAccess) {
            call_user_func($this->checkAccess, $this->id, $model);
        }
    }
}

原创文章， 转载请注明 http://www.cnblogs.com/ganiks/

update

    public function run($id)
    {
        /* @var $model ActiveRecord */
        $model = $this->findModel($id);

        if ($this->checkAccess) {
            call_user_func($this->checkAccess, $this->id, $model);
        }

        $model->scenario = $this->scenario;
        $model->load(Yii::$app->getRequest()->getBodyParams(), '');
        $model->save();

        return $model;
    }

经过改造后，需要满足对关联模型的update动作

    public function run($id)
    {
        /* @var $model ActiveRecord */
        $model = $this->findModel($id);

        if ($this->checkAccess) {
            call_user_func($this->checkAccess, $this->id, $model);
        }

        $model->scenario = $this->scenario;
		/*
		 *
		 * x-www-form-urlencoded key=>value
		 * image mmmmmmmm
		 * link  nnnnnnnnnn
		 * newsItem[title]=>ttttttttttt , don't use newsItem["title"]
		 * newsItem[body]=>bbbbbbbbbbb
		 * don't use newsItem=>array("title":"tttttt","body":"bbbbbbb")
		 * don't use newsItem=>{"title":"ttttttt","body":"bbbbbbbb"}
		 *
		 */
		$newsItem = Yii::$app->getRequest()->getBodyParams()['newsItem'];
		/*
			Array
			(
				[title] => ttttttttttt
				[body] => bbbbbbbbbbb
			)
		 */
		$model->newsItem->load($newsItem, '');
		#$model->newsItem->load(Yii::$app->getRequest()->getBodyParams(), '');
		#print_R($model->newsItem);exit;
		#print_R($model->newsItem);exit;
		if($model->save())
		{
			$model->load(Yii::$app->getRequest()->getBodyParams(), '');
			$model->newsItem->save();
		}

        return $model;
    }

这里还应该对 newsItem save 失败 的情况进行处理，暂且不处理。