     
     private func mockedResponseFilePath(url: NSURL)->String? {
         
+        return mockedFilePath(mockedResponseFileName(url))
+    }
+    
+    private func mockedResponseHeadersFilePath(url: NSURL)->String? {
+        
+        return mockedFilePath(mockedResponseHeadersFileName(url))
+    }
+    
+    private func mockedFilePath(fileName: String?)->String? {
+        
         let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true) as NSArray
         let documentsDirectory = paths[0] as? String
         
-        guard let fileName =  mockedResponseFileName(url),
+        guard let fileName =  fileName,
             let filePath = documentsDirectory?.stringByAppendingString("/\(fileName)") else {
                 return nil
         }

        }
    }
    
}

// MARK: File extension

        urlString = urlString.substringFromIndex(urlString.endIndex.advancedBy(-fromIndex))
        guard let fileName = urlString.stringByAddingPercentEncodingWithAllowedCharacters(.URLHostAllowedCharacterSet()) else {
            fatalError("You must provide a request with a valid URL")
        }
        if isData {
            return  fileName + "DATA." + fileType(mimeType(url))
        }
        return  fileName + "." + fileType(mimeType(url))
    }
