input-file-upload.md

Uploading Files

Note: This section is under development.

Uploading files in Yii is done via form model, its validation rules and some controller code. Let's review what's needed to handle uploads properly.

Form model

First of all, you need to create a model that will handle file upload. Create models/UploadForm.php with the following content:

namespace app\models;

use yii\base\Model;
use yii\web\UploadedFile;

/**
 * UploadForm is the model behind the upload form.
 */
class UploadForm extends Model
{
    /**
     * @var UploadedFile|Null file attribute
     */
    public $file;

    /**
     * @return array the validation rules.
     */
    public function rules()
    {
        return [
            [['file'], 'file'],
        ];
    }
}

In the code above, we created a model UploadForm with an attribute $file that will become <input type="file"> in the HTML form. The attribute has the validation rule named file that uses [[yii\validators\FileValidator|FileValidator]].

Form view

Next create a view that will render the form.

<?php
use yii\widgets\ActiveForm;

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

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

<button>Submit</button>

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

The 'enctype' => 'multipart/form-data' is important since it allows file uploads. fileInput() represents a form input field.

Controller

Now create the controller that connects form and model together:

namespace app\controllers;

use Yii;
use yii\web\Controller;
use app\models\UploadForm;
use yii\web\UploadedFile;

class SiteController extends Controller
{
    public function actionUpload()
    {
        $model = new UploadForm();

        if (Yii::$app->request->isPost) {
            $model->file = UploadedFile::getInstance($model, 'file');

            if ($model->validate()) {                
                $model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);
            }
        }

        return $this->render('upload', ['model' => $model]);
    }
}

Instead of model->load(...) we are using UploadedFile::getInstance(...). [[\yii\web\UploadedFile|UploadedFile]] does not run the model validation. It only provides information about the uploaded file. Therefore, you need to run validation manually via $model->validate(). This triggers the [[yii\validators\FileValidator|FileValidator]] that expects a file:

$file instanceof UploadedFile || $file->error == UPLOAD_ERR_NO_FILE //in code framework

If validation is successful, then we're saving the file:

$model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);

If you're using "basic" application template then folder uploads should be created under web.

That's it. Load the page and try uploading. Uplaods should end up in basic/web/uploads.

Additional information

Required rule

If you need to make file upload mandatory use skipOnEmpty like the following:

public function rules()
{
    return [
        [['file'], 'file', 'skipOnEmpty' => false],
    ];
}

MIME type

It is wise to validate type of the file uploaded. FileValidator has property $types for the purpose:

public function rules()
{
    return [
        [['file'], 'file', 'types' => 'gif, jpg',],
    ];
}

The thing is that it validates only file extension and not the file content. In order to validate content as well use mimeTypes property of ImageValidator:

public function rules()
{
    return [
        [['file'], 'image', 'mimeTypes' => 'image/jpeg, image/png',],
    ];
}

Uploading multiple files

If you need download multiple files at once some adjustments are required. View:

<?php
use yii\widgets\ActiveForm;

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

if ($model->hasErrors()) { //it is necessary to see all the errors for all the files.
    echo '<pre>';
    print_r($model->getErrors());
    echo '</pre>';
}
?>

<?= $form->field($model, 'file[]')->fileInput(['multiple' => '']) ?>

    <button>Submit</button>

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

The difference is the following line:

<?= $form->field($model, 'file[]')->fileInput(['multiple' => '']) ?>

Controller:

namespace app\controllers;

use Yii;
use yii\web\Controller;
use app\models\UploadForm;
use yii\web\UploadedFile;

class SiteController extends Controller
{
    public function actionUpload()
    {
        $model = new UploadForm();

        if (Yii::$app->request->isPost) {

            $files = UploadedFile::getInstances($model, 'file');

            foreach ($files as $file) {

                $_model = new UploadForm();

                $_model->file = $file;

                if ($_model->validate()) {
                    $_model->file->saveAs('uploads/' . $_model->file->baseName . '.' . $_model->file->extension);
                } else {
                    foreach ($_model->getErrors('file') as $error) {
                        $model->addError('file', $error);
                    }
                }
            }

            if ($model->hasErrors('file')){
                $model->addError(
                    'file',
                    count($model->getErrors('file')) . ' of ' . count($files) . ' files not uploaded'
                );
            }

        }

        return $this->render('upload', ['model' => $model]);
    }
}

The difference is UploadedFile::getInstances($model, 'file'); instead of UploadedFile::getInstance($model, 'file');. Former returns instances for all uploaded files while the latter gives you only a single instance.