Using session state in http handler

Question

I have an HTTP Handler that requires access to session state. After reading some other questions on SO, I discovered that I needed to add IReadOnlySessionState to my handler in order to get session state. I did that, and now I can see in my IHttpHandler.ProcessRequest() that context.Session has a value.

This is good, but the problem is now context.Request.HttpMethod is always a GET. If I remove IReadOnlySessionState, context.Request.HttpMethod is POST which is what I expect. So somehow adding IReadOnlySessionState has caused it to change my HttpMethod to GET, and I don't know why.

My code looks something like this:

public class MyHttpHandler : IHttpHandler, IReadOnlySessionState
{
    bool IHttpHandler.IsReusable
    {
        get { return true; }
    }

    void IHttpHandler.ProcessRequest(HttpContext context)
    {
        try
        {
            switch (context.Request.HttpMethod)
            {
                case "GET":
                    HandleGet(context);
                    break;
                case "POST":
                    HandlePost(context);
                    break;
                case "PUT":
                    HandlePut(context);
                    break;
                case "DELETE":
                    HandleDelete(context);
                    break;
                default:
                    break;
            }
        }
        catch (Exception ex)
        {
            // Do something useful here
        }
    }
}

I'm invoking the handler using WinHttp in C++:

HINTERNET hRequest = WinHttpOpenRequest(hConnection, _T("POST"), webServicePath, NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, WINHTTP_FLAG_REFRESH);

BOOL rc = WinHttpSendRequest(hRequest, _T("Content-Type: application/x-www-form-urlencoded"), -1, (LPVOID)content, reqLen, reqLen, NULL);

Passing "POST" to WinHttpOpenRequest() as the method, then sending the request with WinHttpSendRequest()

Answer 1

I fixed it, but I'd still like an explanation if anyone can help - I had <sessionState cookieless="true"/> in my web.config. When I changed that to false, my request came through as a POST. Can anybody explain why?

Answer 2

IRequireSessionState will work with POST requests, like this:

public class MyHttpHandler : IHttpHandler, IRequireSessionState

Read IRequiresSessionState Interface for documentation.