The error "cannot be empty" when saving () due to the rule of checking the "file"

Question

I got this error when the image file is required: "Preview cannot be empty." Although I filled out this field.

My rules:

public function rules()
{
    return [
        [['name', 'preview', 'date', 'author_id'], 'required', 'on' => 'update'],
        [['name', 'preview', 'date', 'author_id'], 'required', 'on' => 'create'],
        [['date_create', 'date_update', 'author_id'], 'integer'],
        [['preview'], 'file', 'skipOnEmpty' => 'false', 'extensions' => 'png, jpg, jpeg'],
        [['date'], 'safe'],
        [['name'], 'string', 'max' => 255]
    ];
}

Controller:

public function actionCreate()
{
    $model = new Book();
    $model->scenario = 'create';
    if ($model->load(Yii::$app->request->post()) && $model->validate()) {
        $model->preview = UploadedFile::getInstance($model, 'preview');
        if ($model->save() && $model->preview->saveAs('uploads/' . $model->preview->baseName . '.' . $model->preview->extension))
        {
            return $this->redirect(['view', 'id' => $model->id]);
        }
    } else {
        return $this->render('create', [
            'model' => $model,
        ]);
    }
}

If the file is previewnot required, there is no error, and the file is downloaded to the folder uploads.

Answer 1

It’s best not to use the same field for different purposes.

In your case, you are rewriting previewwith an instance UploadedFile, you can create another field for this, and then:

$model->previewFile = UploadedFile::getInstance($model, 'preview');

, save(), preview, previewFile, preview $model->validate().

Answer 2

, , $_POST. $_FILES, - $_POST. , $_POST.

. , , :

public function actionCreate()
{
    $model = new Book();
    $model->load(Yii::$app->request->post());
    $model->scenario = 'create';
    $model->preview = UploadedFile::getInstance($model, 'preview');
    if ($model->validate()) {
        if ($model->save() && $model->preview->saveAs('uploads/' . $model->preview->baseName . '.' . $model->preview->extension))
        {
            return $this->redirect(['view', 'id' => $model->id]);
        }
    } else {
        return $this->render('create', [
            'model' => $model,
        ]);
    }
}

, - .

P.S. , "skipOnEmpty" = > false, "" false.