WCF POST method doesn't get called

I've created a WCF REST service and initially used .Net Framework version 4. The service has two methods, one returns a plain string with the service status. The second allows a file to be uploaded. Both methods were working fine.

I was asked to see if the project could be moved back to only depend on .Net Framework 3.5 instead of version 4. I changed some references, and it built ok, and when I use the existing C++ client I can use the GetStatus method fine. However, now when a file gets uploaded, the client sees successful return codes to all methods, but, when I set a breakpoint at the start of WCF service's FileUpload method, it never gets executed. The file doesn't gets uploaded, it just disappears into the ether.

[ServiceContract]
internal interface IMyWebService
{
    [OperationContract]
    [WebGet(UriTemplate = "/Status", BodyStyle=WebMessageBodyStyle.Bare)]
    Stream GetStatus();

    [OperationContract]
    [WebInvoke(Method = "POST", UriTemplate = "/FileUpload/{fileName}")]
    Stream FileUpload(string fileName, Stream fileStream);
}

I've tried to use the开发者_开发技巧 WFetch tool as an alternative client. When I call the FileUpload method, I get this log:

started....WWWConnect::Close("localhost","80")\nclosed source port: 15800\r\n
WWWConnect::Connect("localhost","80")\nIP = "[::1]:80"\nsource port: 15866\r\n
REQUEST: **************\nPOST http://myMachine/MyService/FileUpload/hello.txt HTTP/1.1\r\n
Host: localhost\r\n
Accept: */*\r\n
Content-Length:11\r\n
\r\n
hello thereRESPONSE: **************\nHTTP/1.1 415 Missing Content Type\r\n
Content-Length: 0\r\n
Server: Microsoft-HTTPAPI/2.0\r\n
Date: Thu, 22 Sep 2011 13:26:09 GMT\r\n
\r\n
finished.

Could anybody give me any pointers for how I can diagnose this issue? I'm having trouble seeing where to start because no breakpoints get hit, and there are no error codes to investigate.

The WCF service must be doing something, because if I stop it, the client then fails to upload files, I just can't understand why execution never gets to the method that implements the POST operation.

Hmm, when using WFetch, even if I misspell the name of the method, it still seems to succeed with no error.

Thanks.

I'd start troubleshooting with the original 4.0 version of the service and a C# WCF-based test client to verify the service code will actually upload a file successfully. You could use the code in this Technet article for developing the test client.

Next, use your C++ client against the 4.0 service to verify your client will successfully send a file. Lastly, set the service back to 3.5 and see if it still works. To log messages the service is receiving for troubleshooting, look at this MSDN post to configure the built-WCF message logging capability.