Implement restful url in .net where service is implemented using IHTTPHandler

Question

I want to implement a restful service in ASP.NET. I want it to be compatible with .Net 2.0 and IIS 5+. I am constrained to not use ASP.NET MVC or REST starter kit. By reading on internet I have learned that it can be implemented using HTTPHandlers. The problem is, the request will come in as a POST request. And I want to URL to be like:

http://abc.com/MyService/MyMethod1/ and http://abc.com/MyService/MyMethod2/

Any workarounds for this?

Thanks, Vamyip

Answer 1

Your best option is to use URL Rewriting. This is non-trivial in IIS5. The methods I know of are as follows:

Method 1 - ISAPI filter

These are low-level modules that allow you to manipulate the incoming request. Programming one of these is hairy and tough to debug. If you go this route, you are better off using one that has already been built like ISAPI_Rewrite.

Method 2 - IHttpModule

These are managed ASP.Net modules that are easy to add/remove from your application. Again, you are better off using a pre-built component like UrlRewriter.NET. The issue with using one of these, (as BrainLy mentions), is that you have to configure IIS 5 to map all incoming requests to ASP.Net as follows (link):

1. Open Up IIS and Navigate to the “Home Directory Tab”
2. Select “Configuration”
3. Click “Add” and enter “C:\WINNT\Microsoft.NET\Framework\v2.0.50727\aspnet_isapi.dll” in the Executable box. For the file extension, enter “.*”. Finally, make sure that “Check that file exists” is not checked.

One interesting thing to note is that ASP.Net is itself an ISAPI module :)

Once you are able to manipulate URLs using one of these tools, you can easily rewrite the RESTful urls to be handled by your default.aspx page (or whatever handler you choose to use).

Answer 2

If you can allow the restriction of only IIS 7.0 and above you could use URL Rewrite http://www.iis.net/download/URLRewrite to do that pretty easily.

Can I ask why is it that you need to support IIS 5+? That is an 11 year old technology that hopefully people will move out of those platforms in favor of more recent versions. Also keep in mind support for some of those platforms is ending pretty soon.

If the concern is developers running Windows XP I would point out that IIS Express includes version 7.5+ functionality and is available for all platforms Windows XP and above.

Answer 3

I think this will be difficult to do because IIS 5 will not let you handle non ASP.NET file extensions without some additional configuration in IIS. That means you are limited to URLs ending in .aspx etc. To handle URLs like those in your examples you need to map ASP.NET to handle all URLs in IIS, implement some type of URL rewriting, or introduce some kind of hacky 404 redirection.

Once you have the correct mapping in place you can wire up an IHttpHandler, but you will have to parse the incoming request yourself to work out which is /MyService/MyMethod1/ and which is for /MyService/MyMethod2/. If your methods are simple then it is easy to do this with a regular expression.

You should start with a simple handler like this one.