Custom HttpHandlers and different handler types

Question

All literature I see on creating custom handlers deals with associating an extension with a handler, e.g. if I wanted a handler for Ajax requests, I could implement the IHttpHandler interface in an AjaxHandler class.

Now, to have individual instances of AjaxHandlers, e.g. DocAjaxHander, PersonAjaxHandler etc. how would I derive the base AJAX handling of my AjaxHandler class without registering each individual *.ajax page?

Answer 1

It sounds like your assuming 1 HttpHandler = 1 Page or 1 Control, but as I understand, 1 HttpHandler can handle all pages of a certain file extension.

Your Question is not very clear, and your reponse to another answerer makes no sense...

"In fact, it seemed, to me, a lot like I was asking Http handlers, using a .ajax handler as an example."

But I shall assume you are thinking "DocAjaxHander" and "PersonAjaxHandler" should each be created for a "DocAjaxControl" and "PersonAjaxControl" respectively. I dont think that would be neccesary, 1 handler should be able to handle all your ajax requests if you choose to do it that way, but it doesn't feel like the most intuitive solution to me (using HttpHandlers), anyway, onto the details...

every IHttpHandler object needs to implement :

public void ProcessRequest(HttpContext context)

which allows :

context.Response.Write("Your JSON Response in here");

but at the level of 'ProcessRequest()', you have no access to the instance of the control which created the ajax call, or to the 'System.Web.UI.Page' object that holds the control, or anything.

context.Request

to the rescue! With the Request object above you can read QueryStrings, Sessions, an you can determine the path of the original HttpRequest (i.e. PersonAjaxObject may make an ajax call to 'myPersonobjPage.ajax' for its JSON data, but the '.ajax' extention lands the request at your custom http handler and it's ProcessRequest method.)

If I was you, and I was going to use an HttpHandler for my ajax calls, I'd use query string data to provide enough info for my handler to know 'what type of object am I responding too' as well as 'what data is that object requesting'.

Hope that helps.

Answer 2

You can automatically handle AJAX request in a number of ways. Here's how to do it with a web service:

http://www.asp.net/AJAX/Documentation/Live/Tutorials/ConsumingWebServicesWithAJAXTutorial.aspx

Answer 3

Well, one way to do it would be via query string params...