Uploading files

Uploading files is explained in the guide but it won't hurt to elaborate it a bit more because often, when Active Record model is reused as a form it causes confusion when a field storing file path is reused for file upload.


We'll have a posts manager with a form. In the form we'll be able to upload an image, enter title and text. Image is not mandatory. Existing image path should not be set to null when saving without image uploaded.


We'll need a database table with the following structure:

    title VARCHAR(255) NOT NULL,
    text TEXT NOT NULL,
    image VARCHAR(255)

Next, let's generate Post model with Gii and a CRUD in PostController.

Now we're ready to start.

Post model adjustments

Post model's image stores a path to the image uploaded it should not be confused with the actual file uploaded so we'll need a separate field for that purpose. Since the file isn't saved to database we don't need to store it. Let's just add a public field called upload:

class Post extends \yii\db\ActiveRecord
    public $upload;

Now we need to adjust validation rules:

 * @inheritdoc
public function rules()
    return [
        [['title', 'text'], 'required'],
        [['text'], 'string'],
        [['title'], 'string', 'max' => 255],
        [['upload'], 'file', 'extensions' => 'png, jpg'],

In the above we removed everything concerning image because it's not user input and added file validation for upload.

A form

A form in the views/post/_form.php needs two things. First, we should remove a field for image. Second, we should add a file upload field for upload:

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]); ?>

    <?= $form->field($model, 'title')->textInput(['maxlength' => true]) ?>

    <?= $form->field($model, 'text')->textarea(['rows' => 6]) ?>

    <?= $form->field($model, 'upload')->fileInput() ?>

    <div class="form-group">
        <?= Html::submitButton($model->isNewRecord ? 'Create' : 'Update', ['class' => $model->isNewRecord ? 'btn btn-success' : 'btn btn-primary']) ?>

<?php ActiveForm::end(); ?>

Processing upload

The handling, for simplicity sake, is done in PostController. Two actions: actionCreate and actionUpdate. Both are repetitive so the first step is to extract handling into separate method:

public function actionCreate()
    $model = new Post();

    return $this->render('create', [
        'model' => $model,

public function actionUpdate($id)
    $model = $this->findModel($id);


    return $this->render('update', [
        'model' => $model,

Now let's implement handlePostSave():

protected function handlePostSave(Post $model)
    if ($model->load(Yii::$app->request->post())) {
        $model->upload = UploadedFile::getInstance($model, 'upload');

        if ($model->validate()) {
            if ($model->upload) {
                $filePath = 'uploads/' . $model->upload->baseName . '.' . $model->upload->extension;
                if ($model->upload->saveAs($filePath)) {
                    $model->image = $filePath;

            if ($model->save(false)) {
                return $this->redirect(['view', 'id' => $model->id]);

In the code above right after filling model from POST we're also filling its upload field with an instance of the file uploaded. The important thing is that it should be done before validation. After validating a form, if there's file uploaded we're saving it and writing path into model's image field. Last, regular save() is called with a false argument which means "don't validate". It's done this way because we've just validated above and sure it's OK.

That's it. Objective achieved.

A note on forms and Active Record

For the sake of simplicity and laziness, Active Record is often reused for forms directly. There are scenarious making it doable and usually it doesn't cause any problems. However, there are situations when what's in the form actually differs from what is saved into database. In this case it is preferrable to create a separate form model which is not Active Record. Data saving should be done in this model instead of controller directly.