Getting an extension of an uploaded file in yii2 - php

Question

I'm trying to get an extension of a file during upload but I get an error that path info requires a string:
I have tried:
$path_parts = pathinfo($_FILES['evidence']['name']);
echo $path_parts['extension'];
How can extract file extension, for example jpeg, doc, pdf, etc.

Answer 1

If you are using yii2 kartik file input you can get the instance of yii\web\uploadedFile this way to:
$file = UploadedFile::getInstanceByName('evidence'); // Get File Object byName
// Then you can get extension by this:
$file->getExtension()
If you want to validate file as well then you can use FileValidator using adhoc role:
$validator = new FileValidator(['extensions' => ['png','jpg']]);
if( $validator->validate($file, $errors) ) {
// Validation success now you can save file using $file->saveAs method
} else {
// ToDO with error: print_r($errors);
}

Answer 2

It's better not use $_FILES directly in Yii2 since framework provides abstraction with a class yii\web\UploadedFile. There is also separate page in guide describing working with uploaded files.
There is an example with model.
namespace app\models;
use yii\base\Model;
use yii\web\UploadedFile;
class UploadForm extends Model
{
/**
* #var UploadedFile
*/
public $imageFile;
public function rules()
{
return [
[['imageFile'], 'file', 'skipOnEmpty' => false, 'extensions' => 'png, jpg'],
];
}
public function upload()
{
if ($this->validate()) {
$this->imageFile->saveAs('uploads/' . $this->imageFile->baseName . '.' . $this->imageFile->extension);
return true;
} else {
return false;
}
}
}
As you can see, extension is extracted using extension property ($this->imageFile->extension).
There are more info about form settings, handling in controller, uploading multiple files. All this can be found by the link mentioned above.