When Session objects don't update

Thursday, January 5, 2006

.NET

This is weird. I did that little HttpHandler that generates images in the simple NewsBlog app. It saves a sequence of characters to Session so the (hopefully not blind) user has to type in the stuff on the graphic and confirm they're a human.

On my dev machine, works like a champ running it from VS. I deploy it to the server, and it saves the first set of letters to Session, but subsequent calls do not. Here's the code from the handler...

    public void ProcessRequest(HttpContext context)
    {
    ...
        context.Session.Remove("antispamimage");
        context.Session.Add("antispamimage", s.ToString());
        context.Response.End();
    }

Why do you suppose it doesn't work right on the server?

10 Comments

That should work, by I'm just curious....Couldn't you just to the following...

context.Session("antispamimage") = s.ToString();

context.Response.End();

Also, why the context.Response.End() line?

John Walker - Thursday, January 5, 2006 2:00:00 AM

I did set it that way originally... I was just trying other things for the sake of doing so.

Jeff - Thursday, January 5, 2006 2:02:00 AM

Is the image cached on the browser?

Steven - Thursday, January 5, 2006 2:53:00 AM

another question: is this not a topic for a forum? and not for a blog?

Hannes Preishuber - Thursday, January 5, 2006 6:25:00 AM

Hannes, surely jeff can post what he likes on his blog?

zzzzzzzzzzzz - Thursday, January 5, 2006 7:20:00 AM

Does it work when you take out the context.Response.End() call? Response.End() will 'immediately' stop the execution of the page, by throwing a ThreadAbortException. It is likely that this results in not a session object that is not persisted properly.

For more information see Bertrand's blog post: http://weblogs.asp.net/bleroy/archive/2004/08/03/207486.aspx

Wilco Bauwer - Thursday, January 5, 2006 8:04:00 AM

I'll have to try that, but it doesn't make sense that it works at home in the VS server but not in IIS.

Jeff - Thursday, January 5, 2006 9:08:00 AM

It sort of makes sense that different server could have different behaviors.

Did you try on IIS "at home"?

AndrewSeven - Thursday, January 5, 2006 9:21:00 AM

I haven't looked into this, by my guess is that the difference is between IIS' worker request (which is ISAPIWorkerRequest or something like that) and Cassini's worker request (which is a derivation of SimpleWorkerRequest IIRC). Like AndrewSeven suggested - try the same thing at home on IIS and I am pretty confident that it will fail there aswell.

Wilco Bauwer - Thursday, January 5, 2006 10:18:00 AM

Still no joy here... I don't get it. Doesn't make much sense that the Session update runs once but not on subsequent requests.

Jeff - Thursday, January 5, 2006 8:53:00 PM

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