         }
     }
     
-    func serializedRequestBody() -> NSData {
+    func serializedRequestBody() -> NSData? {
         return queryString().dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: true)
     }
     

    
    var url: NSURL
    var method = "GET"
    var body = NSData()
    var headers: Dictionary<String, String> = Dictionary()
    var parameters: Dictionary<String, String> = Dictionary()
    var connection: NSURLConnection?

            request.setValue(value, forHTTPHeaderField: field)
        }
        
        if let validBody = body {
            if (validBody.length > 0) {
                request.setValue(String(validBody.length), forHTTPHeaderField: "Content-Length")
            }
        }
        
        return request
