## Yii返回指定格式的RESTful json
- 期望的返回格式，同时自动转换需要的内容
``` json
{
"code":0,
"msg":"OK", // 自动封装code 和 msg
"data":[] // yii return 的内容赋值给data
}
```
#### 新增 backend\extensions\ResBeforeSendBehavior.php 继承自Behavior
``` php
namespace backend\extensions;
use Yii;
use yii\web\Response;
use yii\base\Behavior;
use common\models\Users;
class ResBeforeSendBehavior extends Behavior{
public $defaultCode = 500;
public $defaultMsg = 'error';
// 重载events() 使得在事件触发时，调用行为中的一些方法
public function events() {
// 在 EVENT_BEFORE_SEND 事件触发时，调用成员函数 beforeSend
return [
Response::EVENT_BEFORE_SEND => 'beforeSend',
];
}
public function beforeSend($event)
{
$response = $event->sender;
$status = $response->getStatusCode();
$response->data = [
'code' => $status == 200 ? 0 : $status ,
'data' => $response->data,
'msg' => $response->statusText
];
$response->format = yii\web\Response::FORMAT_JSON;
return true;
}
}
```
#### 新增 backend\components\Exception.php 处理异常响应
``` php
namespace backend\components;
use yii\web\ErrorHandler;
use common\models\Users;
class Exception extends ErrorHandler {
/**
* 重写渲染异常页面方法
* @param type $exception
*/
public function renderException($exception) {
$code = $exception->getCode();
if( intval($code) == 0 ){
$code = 500;
}
$data = [
'code' => $code,
'msg' => $exception->getMessage()
//'callback' =>$_GET['callback'],
];
$data['data'] = [];
if(YII_DEBUG){
$data['data'] = [
'file' => $exception->getFile(),
'line' => $exception->getLine(),
'trace' => $exception->getTraceAsString()
];
}
header('Content-Type: application/json; charset=utf-8');
echo json_encode( $data , JSON_UNESCAPED_UNICODE );
//header('Content-Type: application/javascript; charset=utf-8');//for jsonp
//echo $_GET['callback'].'('.json_encode($data).')';
die;
}
}
```
#### 在 backend/config/main.php中增加配置，修改errorHandler和response，设置为自定义的类处理响应
``` php
...
'errorHandler' => [
'errorAction' => 'site/error',
'class' => 'backend\components\Exception'
],
...
'response' => [
'class' => 'yii\web\Response',
'as resBeforeSend' => [
'class' => 'backend\extensions\ResBeforeSendBehavior',
],
],
...
```
#### 完成，这样响应就会自动封装格式，异常也能响应一样的格式