Uploading Files
===============
Uploading files in Yii is done via the a form model, its validation rules and some controller code. Let's review what's
required to handle uploads properly.
Uploading single file
---------------------
First of all, you need to create a model that will handle file uploads. Create `models/UploadForm.php` with the following
content:
```php
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 file attribute
*/
public $file;
/**
* @return array the validation rules.
*/
public function rules()
{
return [
[['file'], 'file'],
];
}
}
```
In the code above, we've created a model `UploadForm` with an attribute `$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
< ?php
use yii\widgets\ActiveForm;
?>
<?php $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 necessary because it allows file uploads. `fileInput()` represents a form
input field.
### Controller
Now create the controller that connects the form and model together:
```php
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->file & & $model->validate()) {
$model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);
}
}
return $this->render('upload', ['model' => $model]);
}
}
```
Instead of `model->load(...)` , we are using `UploadedFile::getInstance(...)` . [[\yii\web\UploadedFile|UploadedFile]]
does not run the model validation, rather it only provides information about the uploaded file. Therefore, you need to run the validation manually via `$model->validate()` to trigger the [[yii\validators\FileValidator|FileValidator]] that expects a file:
```php
$file instanceof UploadedFile || $file->error == UPLOAD_ERR_NO_FILE //in the code framework
```
If validation is successful, then we're saving the file:
```php
$model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);
```
If you're using the "basic" application template, then folder `uploads` should be created under `web` .
That's it. Load the page and try uploading. Uploads should end up in `basic/web/uploads` .
Validation
----------
It's often required to adjust validation rules to accept certain files only or require uploading. Below we'll review
some common rule configurations.
### Required
If you need to make the file upload mandatory, use `skipOnEmpty` like the following:
```php
public function rules()
{
return [
[['file'], 'file', 'skipOnEmpty' => false],
];
}
```
### MIME type
It is wise to validate the type of file uploaded. FileValidator has the property `$extensions` for this purpose:
```php
public function rules()
{
return [
[['file'], 'file', 'extensions' => 'gif, jpg',],
];
}
```
Keep in mind that only the file extension will be validated, but not the actual file content. In order to validate the content as well, use the `mimeTypes` property of `FileValidator` :
```php
public function rules()
{
return [
[['file'], 'file', 'extensions' => 'jpg, png', 'mimeTypes' => 'image/jpeg, image/png',],
];
}
```
[List of common media types ](http://en.wikipedia.org/wiki/Internet_media_type#List_of_common_media_types )
### Image properties
If you upload an image, [[yii\validators\ImageValidator|ImageValidator]] may come in handy. It verifies if an attribute
received a valid image that can be then either saved or processed using the [Imagine Extension ](https://github.com/yiisoft/yii2/tree/master/extensions/imagine ).
Uploading multiple files
------------------------
If you need to upload multiple files at once, some adjustments are required.
Model:
```php
class UploadForm extends Model
{
/**
* @var UploadedFile|Null file attribute
*/
public $file;
/**
* @return array the validation rules.
*/
public function rules()
{
return [
[['file'], 'file', 'maxFiles' => 10], // < --- here !
];
}
}
```
View:
```php
< ?php
use yii\widgets\ActiveForm;
$form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]);
?>
<?= $form->field($model, 'file[]')->fileInput(['multiple' => true]) ?>
< button > Submit< / button >
<?php ActiveForm::end(); ?>
```
The difference is the following line:
```php
<?= $form->field($model, 'file[]')->fileInput(['multiple' => true]) ?>
```
Controller:
```php
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) {
$model->file = UploadedFile::getInstances($model, 'file');
if ($model->file & & $model->validate()) {
foreach ($model->file as $file) {
$file->saveAs('uploads/' . $file->baseName . '.' . $file->extension);
}
}
}
return $this->render('upload', ['model' => $model]);
}
}
```
There are two differences from single file upload. First is that `UploadedFile::getInstances($model, 'file');` used
instead of `UploadedFile::getInstance($model, 'file');` . The former returns instances for **all** uploaded files while
the latter gives you only a single instance. The second difference is that we're doing `foreach` and saving each file.
