web\Response sendFile()

Sends a file to the browser.

Note that this method only prepares the response for file sending. The file is not sent until send() is called explicitly or implicitly. The latter is done after you return from a controller action.

The following is an example implementation of a controller action that allows requesting files from a directory that is not accessible from web:

public function actionFile($filename)
{
    $storagePath = Yii::getAlias('@app/files');

    // check filename for allowed chars (do not allow ../ to avoid security issue: downloading arbitrary files)
    if (!preg_match('/^[a-z0-9]+\.[a-z0-9]+$/i', $filename) || !is_file("$storagePath/$filename")) {
        throw new \yii\web\NotFoundHttpException('The file does not exists.');
    }
    return Yii::$app->response->sendFile("$storagePath/$filename", $filename);
}

See also:

• sendContentAsFile()
• sendStreamAsFile()
• xSendFile()