php - "An error occurred while handling another error: yii\web\HeadersAlreadySentException"

Question

我正在尝试对基于 Yii 2 框架的留言簿应用程序提交评论。在我的 PC 上的本地主机上一切正常，但在共享主机上，当我想在 View 中提交评论时，出现此错误。

这里是错误:

An error occurred while handling another error:
    exception 'yii\web\HeadersAlreadySentException' with message 'Headers already sent in /home/mahdikas/public_html/guestbook/controllers/PostController.php on line 117.' in /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/web/Response.php:366
    Stack trace:
    #0 /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/web/Response.php(339): yii\web\Response->sendHeaders()
    #1 /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/web/ErrorHandler.php(135): yii\web\Response->send()
    #2 /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/base/ErrorHandler.php(111): yii\web\ErrorHandler->renderException(Object(yii\web\HeadersAlreadySentException))
    #3 [internal function]: yii\base\ErrorHandler->handleException(Object(yii\web\HeadersAlreadySentException))
    #4 {main}
    Previous exception:
    exception 'yii\web\HeadersAlreadySentException' with message 'Headers already sent in /home/mahdikas/public_html/guestbook/controllers/PostController.php on line 117.' in /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/web/Response.php:366
    Stack trace:
    #0 /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/web/Response.php(339): yii\web\Response->sendHeaders()
    #1 /home/mahdikas/public_html/guestbook/vendor/yiisoft/yii2/base/Application.php(392): yii\web\Response->send()
    #2 /home/mahdikas/public_html/guestbook/web/index.php(12): yii\base\Application->run()
    #3 {main}

在 postController 中我有这段代码:

public function actionAdd_comment()
{
  //print_r($_POST);
  $model = new \app\models\Comments;
  if ($model->load(Yii::$app->request->post()) && $model->validate()) {
    $model->comment_date = date('Y-m-d H:i:s');
    if ($model->save()) {
      echo 'Thanks for your comment.';
    } else {
      echo 'Failed!';
    }
  }
}

错误中第117行是:

echo 'Thanks for your comment.';

我该如何解决这个问题？

Answer 1

从 Yii 2.0.14 开始，您不能在 Controller 中回显。必须返回响应:

public function actionAdd_comment() {
    $model = new \app\models\Comments();
    if ($model->load(Yii::$app->request->post()) && $model->validate()) {
        $model->comment_date = date('Y-m-d H:i:s');
        if ($model->save()) {
            return 'Thanks for your comment.';
        } else {
            return 'Failed!';
        }
    }
}

---

您也可以调用exit在你的方法结束时防止进一步处理或用 ob_start() 包装你的代码和 ob_get_clean() ，如果您无法避免 echo 。

public function actionAdd_comment() {
    $model = new \app\models\Comments();
    if ($model->load(Yii::$app->request->post()) && $model->validate()) {
        $this->someMagicWithEcho();
        exit;
    }
}

或

public function actionAdd_comment() {
    $model = new \app\models\Comments();
    if ($model->load(Yii::$app->request->post()) && $model->validate()) {
        ob_start();
        $this->someMagicWithEcho();
        return ob_get_clean();
    }
}