add Image and Upload helper classes

common/components/Upload.php

@@ -0,0 +1,50 @@
+<?php
+namespace common\components;
+
+use Yii;
+use yii\web\UploadedFile;
+use \yii\web\HttpException;
+use yii\helpers\Inflector;
+use yii\helpers\StringHelper;
+use yii\helpers\FileHelper;
+
+class Upload
+{
+    public static $UPLOADS_DIR = 'uploads';
+
+    public static function file(UploadedFile $fileInstance, $dir = '', $namePostfix = true)
+    {
+        $fileName = Upload::getUploadPath($dir) . DIRECTORY_SEPARATOR . Upload::getFileName($fileInstance, $namePostfix);
+
+        if(!$fileInstance->saveAs($fileName)){
+            throw new HttpException(500, 'Cannot upload file "'.$fileName.'". Please check write permissions.');
+        }
+        return Upload::getLink($fileName);
+    }
+
+    static function getUploadPath($dir)
+    {
+        $uploadPath = $dir = Yii::getAlias('@frontend/web').DIRECTORY_SEPARATOR.self::$UPLOADS_DIR.($dir ? DIRECTORY_SEPARATOR.$dir : '');
+        if(!FileHelper::createDirectory($uploadPath)){
+            throw new HttpException(500, 'Cannot create "'.$uploadPath.'". Please check write permissions.');
+        }
+        return $uploadPath;
+    }
+
+    static function getLink($fileName)
+    {
+        return str_replace('\\', '/', str_replace(Yii::getAlias('@frontend/web'), '', $fileName));
+    }
+
+    static function getFileName($fileInstanse, $namePostfix = true)
+    {
+        $baseName = str_ireplace('.'.$fileInstanse->extension, '', $fileInstanse->name);
+        $fileName =  StringHelper::truncate(Inflector::slug($baseName), 32, '');
+        if($namePostfix || !$fileName) {
+            $fileName .= ($fileName ? '-' : '') . substr(uniqid(md5(rand()), true), 0, 10);
+        }
+        $fileName .= '.' . $fileInstanse->extension;
+
+        return $fileName;
+    }
+}