Getting a POST endpoint to work in self-hosted (WebServiceHost) C# webservice?

Question

So, I have been messing around with webservices for a while now, and I keep getting back to some basics, that I never seem to get right.

Question 1:

When using a WebServiceHost in .NET/C#, you can define a method/endpoint as using GET/POST/etc. Setting up a GET-method is easy and it works pretty much directly, and its easy to understand how it works. For example:

[OperationContract]
[WebInvoke(Method = "GET", UriTemplate = "/PutMessage/{jsonString}", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
string PutMessage(string jsonString);

If I call http:///MyWebService/PutMessage/{MyJsonString} I get passed on the the method, and all is well (more or less).

But then what does it mean when I define this as a POST instead?

[OperationContract]
[WebInvoke(Method = "POST", UriTemplate = "/PutMessage/{jsonString}", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
string PutMessage(string jsonString);

What does the UriTemplate do here? If I do a POST, I expect the data to be contained not in the URI, but in the "data section" of the post. But do I define the variable name in the data section? How does the WebServiceHost/.NET know that what is contained in the "data section" of the post is to be put into the variable jsonString? How do I post the data from the client side (not C#, let's say JQuery instead) so that it is interpreted correctly on the serer side?

(And how does the WebMessageFormat affet things? I have read everywhere about this (MSDN, Stackoverflow etc) but haven't found a clear and good answer.)

Question 2:

In my attempts to understand this, I thought I'd make a very simple POST-method, like this:

[OperationContract]
[WebInvoke]
string PutJSONRequest(string pc);

I then try call this method using Fiddler, but that does not work at all. I just get a 400 error back, saying "HTTP/1.1 400 Bad Request". I have a breakpoint on the very first line in the code of the method, and the method itself contains nothing:

public string PutJSONRequest(string pc)
{
    return null;
}

Again, how does .NET know that what I POSTed using Fiddler should be contained in the "string pc"? How does it interpret it as a string, and what type of string (UT8, ASCII etc)?

This is the RAW HTTP request, sent from Fiddler:

POST http://<myip>:8093/AlfaCustomerApp/PutJSONRequest HTTP/1.1
User-Agent: Fiddler
Host: <myip>:8093
Content-Length: 3
Content-type: application/x-www-form-urlencoded; charset=UTF-8

asd

and it doesnt matter what type of Content-type I use, as far as I can see.

The response is a standard-thing, that I am not in control of myself:

HTTP/1.1 400 Bad Request
Content-Length: 1165
Content-Type: text/html
Server: Microsoft-HTTPAPI/2.0
Date: Mon, 15 Oct 2012 15:45:02 GMT

[then HTML code]

Any help would be appreciated. Thanks.

Answer 1

I think a simple code can answer all your questions

Task.Factory.StartNew(()=>StartServer());
Thread.Yield();
StartClient();

---

void StartServer()
{
    Uri uri = new Uri("http://localhost:8080/test");
    WebServiceHost host = new WebServiceHost(typeof(WCFTestServer), uri);
    host.Open();
}

void StartClient()
{
    try
    {
        WebClient wc = new WebClient();

        //GET
        string response1 = wc.DownloadString("http://localhost:8080/test/PutMessageGET/abcdef");
        //returns: "fedcba"

        //POST with UriTemplate
        string response2 = wc.UploadString("http://localhost:8080/test/PutMessagePOSTUriTemplate/abcdef",
                                            JsonConvert.SerializeObject(new { str = "12345" }));
        //returns: fedcba NOT 54321


        //POST with BodyStyle=WebMessageBodyStyle.WrappedRequest
        //Request: {"str":"12345"}
        wc.Headers["Content-Type"] = "application/json";
        string response3 = wc.UploadString("http://localhost:8080/test/PutMessagePOSTWrappedRequest",
                                            JsonConvert.SerializeObject(new { str="12345" }));

        //POST with BodyStyle=WebMessageBodyStyle.Bare
        wc.Headers["Content-Type"] = "application/json";
        string response4 = wc.UploadString("http://localhost:8080/test/PutMessagePOSTBare", "12345" );

    }
    catch (WebException wex)
    {
        Console.WriteLine(wex.Message);
    }
}

---

[ServiceContract]
public class WCFTestServer
{
    [OperationContract]
    [WebInvoke(Method = "GET", UriTemplate = "/PutMessageGET/{str}", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
    public string PutMessageGET(string str)
    {
        return String.Join("", str.Reverse());
    }

    [OperationContract]
    [WebInvoke(Method = "POST", UriTemplate = "/PutMessagePOSTUriTemplate/{str}", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
    public string PutMessagePOSTUriTemplate(string str)
    {
        return String.Join("", str.Reverse());
    }

    [OperationContract]
    [WebInvoke(Method = "POST", BodyStyle=WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
    public string PutMessagePOSTWrappedRequest(string str)
    {
        return String.Join("", str.Reverse());
    }

    [OperationContract]
    [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.Bare, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
    public string PutMessagePOSTBare(string str)
    {
        return String.Join("", str.Reverse());
    }
}

---

PS: You can find the JsonConvert here