add checks for HEAD request

framework/yii/web/Request.php

@@ -155,6 +155,15 @@ class Request extends \yii\base\Request
 	}
   
 	/**
+	 * Returns whether this is a HEAD request.
+	 * @return boolean whether this is a HEAD request.
+	 */
+	public function getIsHead()
+	{
+		return $this->getMethod() === 'HEAD';
+	}
+  
+	/**
 	 * Returns whether this is a POST request.
 	 * @return boolean whether this is a POST request.
 	 */