WCF JSON Multiple Parameters

Question

Hi,

I've been experimenting with calling a WCF services from a Windows Mobile device using HttpWebResponse/HttpWebRequest.  The format of the data exchange is Json.  The test service has the following method signature:

public string Process(Data dData)


{
        return string.Format("you entered: {0} {1}", dData.StringValue, dData.BoolValue);
}

When I make the call eveything is fine and I can see a trace of the exchange using TcpTrace.  However when I change the method signature to receive multiple parameters, I receive a HTTP server 500 error.

public string Process(Data dData, Data dData2)
{
       return string.Format("you entered: {0} {1} {2} {3}", dData.StringValue, dData.BoolValue, dData2.StringValue, dData2.BoolValue);
}

The code on the client is as follows:

Data dData1 = new Data();
            dData1.BoolValue = true;
            dData1.StringValue = "Hello WCF World";

            Data dData2 = new Data();
            dData2.BoolValue = false;
            dData2.StringValue = "HW";

            //DataContractJsonSerializer dcjSerialiser = null;
            JsonSerializer jsSerialiser = null;
            //string strJson = null;
            //byte[] bData = null;

            Uri uUri = new Uri("http://localhost:8080/WcfTest/Service.svc/process");

            HttpWebRequest hwrRequest = (HttpWebRequest)WebRequest.Create(uUri);
            hwrRequest.Method = "POST";
            hwrRequest.ContentType = "application/json; charset=utf-8";
            //hwrRequest.ContentLength = bData.Length;

            //using(MemoryStream msStream = new MemoryStream())
            //{
                //dcjSerialiser = new DataContractJsonSerializer(dData1.GetType());
                jsSerialiser = new JsonSerializer();
                jsSerialiser.NullValueHandling = NullValueHandling.Ignore;
                //dcjSerialiser.WriteObject(msStream, dData);

                using(Stream sData = hwrRequest.GetRequestStream())
                {
                    //sData.Write(bData, 0, bData.Length);
                    //dcjSerialiser.WriteObject(sData, dData1);
                    //dcjSerialiser.WriteObject(sData, dData2);

                    using(StreamWriter swWriter = new StreamWriter(sData))
                    {
                        using(JsonWriter jwWriter = new JsonTextWriter(swWriter))
                        {
                            jsSerialiser.Serialize(jwWriter, dData1);
                            jsSerialiser.Serialize(jwWriter, dData2);
                        }
                    }

                    sData.Close();
                }

                //strJson = Encoding.UTF8.GetString(msStream.ToArray());
                //bData = Encoding.UTF8.GetBytes(strJson);
                //msStream.Close();
            //}

            using(HttpWebResponse hwrResponse = (HttpWebResponse)hwrRequest.GetResponse())
            {
                StreamReader srReader = new StreamReader(hwrResponse.GetResponseStream());
                Console.WriteLine(srReader.ReadToEnd());
            }

Is it possible to send multiple parameters?

Any help would be appreciated,

Mark

Answer 1

If you use multiple parameters, you need to "wrap" the request in its own object (and note it on the [WebInvoke] attribute), otherwise you'd get an invalid JSON. For example, the request you're sending is this:

    {"StringValue":"Hello WCF World","BoolValue",true}{"StringValue":"HW","BoolValue":false}

which is not a valid JSON. You need to wrap it like the following:

    {"data1":{"StringValue":"Hello WCF World","BoolValue",true},"data2":{"StringValue":"HW","BoolValue":false}}

And your contract has to be as shown below:

[

OperationContract]
[WebInvoke(BodyStyle = WebMessageBodyStyle.WrappedRequest,
                  RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
string Process(Data dData1, Data dData2);

The code below shows the whole thing end-to-end:

    public class Post_044876ce_2643_4f2b_b9f4_250f920454ae_2Param
    {
        [DataContract]
        public class Data
        {
            [DataMember]
            public string StringValue;
            [DataMember]
            public bool BoolValue;
        }
        [ServiceContract]
        public interface ITest
        {
            [OperationContract]
            [WebInvoke(
                BodyStyle = WebMessageBodyStyle.WrappedRequest,
                RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
            string Process(Data dData1, Data dData2);
        }
        public class Service : ITest
        {
            public string Process(Data dData1, Data dData2)
            {
                if (dData1 == null) { return "dData1 == null"; }
                if (dData2 == null) { return "dData2 == null"; }
                return string.Format("you entered: {0} {1}, {2} {3}",
                    dData1.StringValue, dData1.BoolValue,
                    dData2.StringValue, dData2.BoolValue);
            }
        }
        public static void Test()
        {
            string baseAddress = "http://localhost:8000/Service";
            ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
            host.AddServiceEndpoint(typeof(ITest), new WebHttpBinding(), "").Behaviors.Add(new WebHttpBehavior());
            host.Open();
            Console.WriteLine("Host opened");

            Util.SendRequest(baseAddress + "/Process", "POST", "application/json", "{\"dData1\":{\"BoolValue\":true,\"StringValue\":\"Hello\"}, \"dData2\":{\"BoolValue\":false,\"StringValue\":\"World\"}}");

            Console.Write("Press ENTER to close the host");
            Console.ReadLine();
            host.Close();
        }
    }
    public static class Util
    {
        public static string SendRequest(string uri, string method, string contentType, string body)
        {
            string responseBody = null;

            HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(uri);
            req.Method = method;
            if (!String.IsNullOrEmpty(contentType))
            {
                req.ContentType = contentType;
            }
            if (!String.IsNullOrEmpty(body))
            {
                byte[] bodyBytes = Encoding.UTF8.GetBytes(body);
                req.GetRequestStream().Write(bodyBytes, 0, bodyBytes.Length);
                req.GetRequestStream().Close();
            }

            HttpWebResponse resp;
            try
            {
                resp = (HttpWebResponse)req.GetResponse();
            }
            catch (WebException e)
            {
                resp = (HttpWebResponse)e.Response;
            }
            Console.WriteLine("HTTP/{0} {1} {2}", resp.ProtocolVersion, (int)resp.StatusCode, resp.StatusDescription);
            foreach (string headerName in resp.Headers.AllKeys)
            {
                Console.WriteLine("{0}: {1}", headerName, resp.Headers[headerName]);
            }
            Console.WriteLine();
            Stream respStream = resp.GetResponseStream();
            if (respStream != null)
            {
                responseBody = new StreamReader(respStream).ReadToEnd();
                Console.WriteLine(responseBody);
            }
            else
            {
                Console.WriteLine("HttpWebResponse.GetResponseStream returned null");
            }
            Console.WriteLine();
            Console.WriteLine("  *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*  ");
            Console.WriteLine();

            return responseBody;
        }
    }

Answer 2

Carlos,

Thanks for the reply and code snippet.

Mark

Answer 3

http://arraycode.com/Main/Details/post-multiple-parameters-to-wcf-service-1329

Maybe This will help?

Answer 4

Link doesn't work. FYI