Question

I got this in an interview question — the question was more about what they do, which I didn’t know beyond very vague terms. But after reading about them I’m still no closer to an understanding of what problems I would solve with an HttpHandler or HttpModule. I’ve worked a fair amount in ASP.NET but it’s been a few years — is this a large gap in my knowledge? Something that’s been replaced by more current technology?

Clarification: what’s a common problem in the ASP.NET world that would be much easier to solve with an HttpHandler as opposed to something you’d do in a webservice or an ajax call?

Answer 1

Believe it or not ASP.NET is built using HTTP handlers and HTTP modules to provide default ASP.NET behavior. For a good write-up, please see HTTP Handlers and HTTP Modules Overview:

An ASP.NET HTTP handler is the process
(frequently referred to as the
“endpoint”) that runs in response to a
request made to an ASP.NET Web
application. The most common handler
is an ASP.NET page handler that
processes .aspx files. When users
request an .aspx file, the request is
processed by the page through the page
handler. You can create your own HTTP
handlers that render custom output to
the browser.

An HTTP module is an assembly that is
called on every request that is made
to your application. HTTP modules are
called as part of the ASP.NET request
pipeline and have access to life-cycle
events throughout the request. HTTP
modules let you examine incoming and
outgoing requests and take action
based on the request.