yii2: how to response image and let browser show it?

Question

the same work can be done by follow code：

header(\'Content-Type:image/jpeg\');
readfile(\'a.jpg\');

but now I really confused by Yii2\'s

Answer 1

Yii2 already has built-in function for sending files. This way you do not need to set response format and content type will be detected automatically (you can override it if you wish):

function actionDownload()
{
    $imgFullPath = 'picture.jpg';
    return Yii::$app->response->sendFile($imgFullPath);
}

..

If the file is only temporary created for current download action you can use AFTER_SEND event to delete the file:

function actionDownload()
{
    $imgFullPath = 'picture.jpg';
    return Yii::$app->response
        ->sendFile($imgFullPath)
        ->on(\yii\web\Response::EVENT_AFTER_SEND, function($event) {
            unlink($event->data);
        }, $imgFullPath);
}