Question

I’ve been researching this a bit but haven’t come across an answer — is there any way to programatically add an HttpHandler to an ASP.NET website without adding to the web.config?

Answer 1

By adding an HttpHandler I assume you mean the configuration files

<system.web>
    <httpHandlers>...</httpHandler>
</system.web>

There is a way to control it automatically, by adding the IHttpHandler in directly during the request. So on the PostMapRequestHandler in the Application Lifecycle, you would do the following, in your own custom IHttpModule:

private void context_PostMapRequestHandler(object sender, EventArgs e)
{
    HttpContext context = ((HttpApplication)sender).Context;
    IHttpHandler myHandler = new MyHandler();
    context.Handler = myHandler;
}

And that would automatically set the handler for that request. Obviously you probably want to wrap this in some logic to check for things such as verb, requesting url, etc. But this is how it would be done. Also this is how many popular URL Rewriters work such as:

http://urlrewriter.codeplex.com

Unfortunately though, using the pre built configuration handler that the web.config does, is hidden away and doesn’t seem to be accessible. It is based off an interface called IHttpHandlerFactory.

Update The IHttpHandlerFactory can be used just like any other IHttpHandler, only it is used as a launching point instead of a processing point. See this article.

https://web.archive.org/web/20140227135526/http://www.uberasp.net/getarticle.aspx?id=49