C# REST Service Client and Server

Question

I'm trying to write a simple REST service that I can talk to through my C# application. I want to send the REST service a JSON string and for it to send me a JSON string back. I want to do this using POST not GET as there is a fair amount of data that needs to be sent to it.. Also I would like to do it using what is built into the .net library that I'm using - .NET Framework 4.0.

So far I have the following code:

Client

        public void SendJSONPostRequest(string sFunction, string sJSON)
        {
            string sRequest = FormRequest(m_sWebServiceURL, sFunction, string.Empty);

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(sRequest);
        request.Method = "POST";
        System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
        Byte[] byteArray = encoding.GetBytes(sJSON);
        request.ContentLength = byteArray.Length;
        request.ContentType = @"application/json";

        using (Stream dataStream = request.GetRequestStream())
        {
            dataStream.Write(byteArray, 0, byteArray.Length);
        }
        long length = 0;
        try
        {
            using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
            {
                length = response.ContentLength;
            }
        }
        catch (WebException ex)
        {
            // Log exception and throw as for GET example above
        }
}



public static string FormRequest(string sURL, string sFunction, string sParam)
        {
            StringBuilder sbRequest = new StringBuilder();
            sbRequest.Append(sURL);
            if (!sURL.EndsWith("/"))
            {
                sbRequest.Append("/");
            }
            sbRequest.Append(sFunction);

            if ((!sFunction.EndsWith("/") && 
                (!string.IsNullOrEmpty(sParam))))
            {
                sbRequest.Append("/");
            }
            sbRequest.Append(sParam);

            return sbRequest.ToString();
        }

Server

using System;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.ServiceModel.Activation;
using System.IO;

namespace ExampleRESTService
{
    [ServiceContract(Name = "RESTServices")]
    public interface IRESTServices
    {    
        [OperationContract]
        [WebInvoke(Method = "POST", UriTemplate = Routing.Route, BodyStyle = WebMessageBodyStyle.Bare)]
        string GetCounts();
    }

    public static class Routing
    {            
        public const string Route = "/GetCounts";
    }

   [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Single, IncludeExceptionDetailInFaults = true)]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class RESTServices : IRESTServices
    {
        public string GetCounts()
        {
            string sData = "Hello"
            return sData;
        }
    }
}

Now this isn't all of the code but it is the bits that are important I think. Also I've changed names for display online but it all compiles so please ignore if a typo. Apologies if there is something significant.

The REST service can be called from my client fine as is but my question is...

How do I extract the data in my REST service GetCounts() method that was posted to it from the client, i.e the JSON string?

Thanks in advance.

This looks like WCF. If you're just trying to write a simple REST service, why not use WebAPI? [Here's a link to an SO resource that you might be interested in.](https://stackoverflow.com/questions/9348639/wcf-vs-asp-net-web-api) — Joshua Shearer, Jan 22 '16 at 21:10
`var data = (new StreamReader(Request.InputStream)).ReadToEnd();` or something — Alexandru, Jan 22 '16 at 21:13
I think what you are looking for is `GetCounts(Someobject data)` just define the class for the `Someobject` — Omar Martinez, Jan 22 '16 at 21:18
Hi Thanks. Should I be changing to public string GetCounts([FromBody] string data) If so how should my request be from the client? If it was previously: http://localhost:8000/ExampleRESTService/GetCounts Do I now need a parameter? http://localhost:8000/ExampleRESTService/GetCounts/data (really long) — Yos, Jan 22 '16 at 21:39
If you are doing [FromBody] you don't need a parameter, the url is whatever your Route is set to. — Cleverguy25, Jan 22 '16 at 22:48
Hi Cleverguy25. Thanks for this. However it doesn't work.. The same URL does work if I test in Chromes POSTER but in my C# Client it gives me the following exception: {System.Net.WebException: The remote server returned an error: (400) Bad Request. at System.Net.HttpWebRequest.GetResponse() Do you have any ideas why this might be? Thanks — Yos, Jan 22 '16 at 22:57
In fact it seems to work if I don't post any data strangely! — Yos, Jan 22 '16 at 23:26

score 0 · Answer 1 · edited May 23 '17 at 11:52

0

The response is returned as a stream.

I think you will find that the answer is in this link

How to convert WebResponse.GetResponseStream return into a string?

The sample there which I have used myself plenty of times is as follows

using (Stream stream = response.GetResponseStream())
{
   StreamReader reader = new StreamReader(stream, Encoding.UTF8);
   String responseString = reader.ReadToEnd();
}

if you then want to convert the JSON into a class for easier manipulation then Newtonsoft have a library to serialize and Deserialize to transfer between both.

edited May 23 '17 at 11:52

Community

1
1

answered Jan 22 '16 at 21:11

Paul S Chapman

832
10
37

1

I may be wrong, but it seemed to me like the question was referring to how to access the `POST` data on the server. – Joshua Shearer Jan 22 '16 at 21:12
Hi Thanks, This is really useful and I will use this but for now I need to be able to extract the data in the Web Service Server GetCounts method that I originally POSTed to it? – Yos Jan 22 '16 at 21:40

C# REST Service Client and Server

1 Answers1