Why isn't this WCF service accessible via JSON Ajax?

Question

I have a WCF service that needs to be called via SOAP (working) and via JSON (not working).

My C# code:

[ServiceContract]
public interface IService1
{
    [OperationContract]
    [WebGet(ResponseFormat=WebMessageFormat.Json)]
    string Foo();
}

public class Service1 : IService1
{
    public string Foo()
    {
        return "woohooo";
    }
}

And here's my config:

<?xml version="1.0"?>
<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>
  <system.serviceModel>

    <services>
      <service name="Service1">
        <endpoint address="soap" binding="basicHttpBinding" contract="DummyService.IService1"/>
        <endpoint address="json" binding="webHttpBinding" behaviorConfiguration="jsonBehavior" contract="DummyService.IService1"/>
      </service>
    </services>

    <behaviors>
      <serviceBehaviors>
        <behavior>
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="jsonBehavior">
          <enableWebScript/>
          <webHttp/>
        </behavior>
      </endpointBehaviors>
    </behaviors>

    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />

  </system.serviceModel>
 <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>

</configuration>

And here's my Javascript:

$.getJSON("/Service1.svc/Foo")
    .success(function (result) {
        alert("success! " + result);
    })
    .fail(function (result) {
        console.log("failed!");
        console.log(result);
    });

The response I get is "400 Bad Request". What am I doing wrong? I've followed the advice in REST / SOAP endpoints for a WCF service, but it still-a-no-worksies. :-) Help!

Forgive me if you've done this: In the service behaviour, set IncludeExceptionDetailInFaults to true. In fiddler, look at the Inspectors tab, an in the bottom panel click on TextView. This gives you a wealth of information. — Andrew Shepherd, Nov 02 '11 at 22:23
If you look at the config file, you'll see I have already set IncludeExceptionDetailInFaults to true. I'll check the inspectors tab in Fiddler and let you know the results. Thanks for all your help so far, I feel like we're close to fixing this. — Judah Gabriel Himango, Nov 03 '11 at 14:30
I ended up getting this working via Garret's answer. Thanks for your help in debugging this problem. — Judah Gabriel Himango, Nov 17 '11 at 04:35

Andrew Shepherd · Answer 1 · 2011-11-02T04:22:44.600

1

I'm thinking it's because the URL you are using is an absolute URL, not a relative one.

If you are running this in the ASP.NET debugger, the service would be available on the following address:

http://localhost:52200/Web/Service1.svc

Because you are preceeding the URL with a forward slash, the service query is actually being sent to

http://localhost:52200/Service1.svc

So you need to pass in the appropriate relative address. If your service and the script file are in the same directory, change it to:

$.getJSON("./Service1.svc/Foo")

edited Nov 02 '11 at 04:22

answered Nov 02 '11 at 04:09

Andrew Shepherd

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No luck. The service and script file are in the same directory, and I'm running this under Visual Studio debugger. Looking at the request in Chrome dev tools, it says, "GET http://localhost:4618/Service1.svc/Foo 400 (Bad Request)" – Judah Gabriel Himango Nov 02 '11 at 04:28
@Judah - And what's the request path of the page that is hosting the script? – Andrew Shepherd Nov 02 '11 at 04:34
OK, I'm convinced that that isn't the problem – Andrew Shepherd Nov 02 '11 at 04:59

Garett · Accepted Answer · 2011-11-03T04:22:26.170

Try including the endpoint address in the service URL. Something like:

$.getJSON("/Service1.svc/json/Foo")

Also, you should enable WCF tracing to see what error is being returned. You will need the Service Trace Viewer to view the log information.

UPDATE:

Below is an example using your code that works.

The configuration file contains

<system.serviceModel>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true"/>

    <services>
      <service behaviorConfiguration="jsonServiceBehavior" name="DummyService.Service1">
        <endpoint address="soap" binding="basicHttpBinding" contract="DummyService.IService1"/>
        <endpoint address="json" 
                  behaviorConfiguration="jsonBehavior" 
                  binding="webHttpBinding" contract="DummyService.IService1"/>
      </service>
    </services>

    <behaviors>
      <endpointBehaviors>
        <behavior name="jsonBehavior">
          <webHttp/>
        </behavior>
      </endpointBehaviors>

      <serviceBehaviors>
        <behavior name="jsonServiceBehavior">
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="true"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>

I created an empty web project and added the following HTML page to test the service.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>
    <script src="Scripts/jquery-1.6.4.min.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $.getJSON("/Service1.svc/json/Foo")
            .success(function (result) {
                alert("success! " + result);
            })
            .fail(function (result) {
                console.log("failed!");
                console.log(result);
            });
        });
    </script>
</head>
<body>    

</body>
</html>

And my Service1.svc has the following:

<%@ ServiceHost Language="C#" Service="DummyService.Service1" %>

Tried including the endpoint address, still no luck; result is 400 (Bad Format). — Judah Gabriel Himango, Nov 02 '11 at 05:28
Have you enabled tracing? What is the exact WCF exception? Did you check the event log? You can also try using fiddler to trace the call. — Garett, Nov 02 '11 at 05:58
Just saw your update. It works! Thank you so much, I was just about to rewrite the WCF service as a REST controller, which would have been costly. This preserves my current code, and makes my AJAX workable. Awesome! Thank you. — Judah Gabriel Himango, Nov 17 '11 at 04:34

score 1 · Answer 3 · answered Nov 02 '11 at 04:47

1

Try taking out the <webHttp /> element from the endpoint behavior.

I have a web service that is invoked by Ajax, and it doesn't have this element.

When I tried putting the element in, it stopped working.

(Admittedly, this was to do with not recognizing the date formats, so it's not an exact match for your problem).

answered Nov 02 '11 at 04:47

Andrew Shepherd

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Oops, that was accidental left-over from testing. But still, if I take it out, still no luck, still getting the 400 error (Bad Request) – Judah Gabriel Himango Nov 02 '11 at 05:27
I noticed I didn't paste my whole config file. Can you look at it again? Does it look good to you? – Judah Gabriel Himango Nov 02 '11 at 15:57

score 1 · Answer 4 · answered Nov 02 '11 at 22:43

(My third answer. I know that ONE of these answers is going to be right :-)

Try setting aspNetCompatibilityEnabled to true on the serviceHostingEnvironment.

   <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />

This is just a guess. When I turn this off on my implementation the call still arrives, but HttpContext.Current returns NULL.

Why isn't this WCF service accessible via JSON Ajax?

4 Answers4