Yii2 file upload

//Model
<?php
namespace backend\models;
use Yii;
use yii\web\UploadedFile;
class UploalModel extends \yii\db\ActiveRecord
{
    /**
     * @var UploadedFile|Null file attribute
     */
    public $file;
    /**
     * @return array the validation rules.
     */
    public function rules()
    {
        return [
            [["file"], "file",],
        ];
    }
    /**Public Upload Information (Array) File Name Size Suffix Name Limits Update to Remove Existing Pictures for Update Pictures*/
    public function upload($img,$name = '/vessel',$siez = '',$arr_type = '',$text_name = '',$act='update',$url='/vessel/20180831/153571385083726.jpg')
    {
        $path = '../..';
        $dirname = $path.$name;
        $fill=$this->file->extension;//The name of the picture is suffix only.
        if(empty($text_name)){
            $ran=time().rand(10000,99999);//Random name
        }else{$ran = $text_name;}
        $arr = $arr_type;
        if(!empty($arr)){
            if(!in_array($fill,$arr)){ return json_encode('Incorrect format);}
        }
        //Define upload size and type
        if(!empty($siez)){
            if($img['size']>$siez) {return json_encode('File size exceeds limit.);}
        }
        //Files uploaded and stored
        $dir=$dirname.'/'.date("Ymd");
        $dir_sev=$name.'/'.date("Ymd");/*Database storage path*/
        if(!file_exists($dir)) {
            mkdir($dir,0777,true);
        }
        if ($this->validate()) {
            //file name
            $fileName = $ran .'.'.$fill;
            $dir = $dir."/". $fileName;
            if($act == 'update'){if($this->file->saveAs($dir)){@unlink($path.$url);}}/*Delete the picture*/
            $uploadSuccessPath = $dir_sev."/". $fileName;/*Final path*/
            return $uploadSuccessPath;
        }
    }
}

//Controller
<?php
namespace backend\controllers;
use Yii;
use backend\models\UploalModel;
use yii\web\UploadedFile;
class TestController extends \yii\web\Controller
{
    /**
     *    File upload* we return the address of the picture after the upload is successful.*/
    public function actionIndex ()
    {
        $model = new UploalModel();
        $uploadSuccessPath = "";
        if (Yii::$app->request->isPost) {
            $model->file = UploadedFile::getInstance($model, "file");
            $file = $model->upload((array)$model->file);
            return $file;
        }
        return $this->render("index", [
            "model" => $model,
            "uploadSuccessPath" => $uploadSuccessPath,
        ]);
    }
}

//view
<?php
use yii\widgets\ActiveForm;

$form = ActiveForm::begin(["options" => ["enctype" => "multipart/form-data"]]);
?>
    <input type="hidden" name="UploalModel[file]" value="">
    <input type="file" id="uploalmodel-file" name="UploalModel[file]">
    <button>Submit</button>

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