Develop a HttpHandler with full IntelliSense
Ashx files have a bad reputation. There is
little documentation
about them in v1, and no support for them in Visual Studio
2003. With
ASP.NET
2.0 and Visual Studio 2005, this changes, and it becomes as
easy to develop an ashx file as any other class.
But what is an ashx file, you may ask? It's an
HttpHandler, a class that handles an http request. An
ASP.NET
page
can be considered a kind of elaborate
HttpHandler, for example. There are cases where you won't need all the
Page infrastructure, WebControls, events and all that. Let's
say that you want to stream a thumbnail image to the client,
for example. All you need is a reference to the context (to
be able to get some information from the QueryString, send
data to the response, etc.). That's no more and no less than
what the HttpHandler infrastructure gives you.
So when you need raw treatment of a http request, use a
handler instead of a page.
I've made a few screen copies while developing a very simple
handler, so that you can see how easy it becomes to develop
an ashx file in Visual Studio 2005 (click on the images to
get them at full resolution):
Step 1: Adding a new item to the project. I'm choosing
"generic handler", which will create the ashx file with the
code structure already there.
Step 2: This is the code structure that Visual Studio
provides. I did not write a single character at this
point.
Step 3: I have full IntelliSense and code coloring on my
code. Everything works exactly the same as in any other code
file.
Step 4: I also have access to refactoring, immediate
squiggly red lines under my syntax errors, etc.
Step 5: I can build the page, the whole web site or the
whole solution (or even just save and let the server
auto-compile on the first request).
Step 6: I can see build errors (I made stupid errors on
purpose here, in real life I know how to initialize an
array) and click on them to get to the faulty source
code.
Step 7: I'm almost done. The handler compiles.
Step 8: And it works perfectly!
Update: Scott Hanselman has
a great HttpHandler template
to get you started.