Yii2: can't upload file through FileUploadUI

Question

I'm trying to upload a file through FileUploadUI::widget in yii2 advanced. But I can't achieve my goal. I don't know what the problem is, but the file doesn't appear in the folder I wish to upload to.

this is my view

<?= FileUploadUI::widget([
        'model' => $model,
        'attribute' => 'img',
        'url' => ['image-upload', 'id' => $model],
        'gallery' => false,
        'fieldOptions' => [
            'accept' => 'image/*'
        ],
        'clientOptions' => [
            'maxFileSize' => 2000000
        ],
        // ...
        'clientEvents' => [
            'fileuploaddone' => 'function(e, data) {
                                console.log(e);
                                console.log(data);
                            }',
            'fileuploadfail' => 'function(e, data) {
                                console.log(e);
                                console.log(data);
                            }',
        ],
    ]); ?>

this is controller my controller is into backend but I want to upload the file to frontend/web/img/temp action

public function actionImageUpload()
{
    $model = new MyNews();

    $imageFile = UploadedFile::getInstance($model, 'img');
    $directory = Yii::getAlias('/../frontend/web/img/temp/');

    if ($imageFile != null) { //can't saveAs() file into my ../img/temp/ folder
        $uid = 'qqqq';
        $fileName = $uid . '.' . $imageFile->extension;
        $filePath = $directory . $fileName;
        if ($imageFile->saveAs($filePath)) {
            $path = '/../frontend/web/img/temp/' . $fileName;
             //.....
        }
    }
        return '';
    }

Answer 1

You should use aliases defined by Yii like @frontend @backend rather than providing the path inside the Yii::getAlias(), few common like i stated are defined in common/config/bootstrap.php like

Yii::setAlias ( '@frontend' , dirname ( dirname ( __DIR__ ) ) . '/frontend' );
Yii::setAlias ( '@backend' , dirname ( dirname ( __DIR__ ) ) . '/backend' );

The path you are providing is also wrong because Yii is inside the backend/web/ not at the root of backend app from where you are trying to upload.

What i would suggest is to define your path inside the common/config/bootstrap.php like below

Yii::setAlias('@uploadDir',realpath(Yii::getAlias('@frontend').'/web/img/temp/'));

and then change your code to the following

public function actionImageUpload()
{
    $model = new MyNews();

    $imageFile = UploadedFile::getInstance($model, 'img');
    $directory = Yii::getAlias('@uploadDir');

    if ($imageFile != null) { //can't saveAs() file into my ../img/temp/ folder
        $uid = 'qqqq';
        $fileName = $uid . '.' . $imageFile->extension;
        $filePath = $directory . $fileName;
        if ($imageFile->saveAs($filePath)) {
            Yii::$app->session->setFlash('success','The file has been uploaded successfuly');
            return $this->redirect('index');
        }
    }

}