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Improved URL Mapping for Castle MonoRail

Hammett announced a new MonoRail Routing Engine on his blog. The Routing Engine is responsible for mapping URL patterns to Controller actions, which has been a weakness of MonoRail so far. As Hammett stated on his blog, the need for an improvement has mainly been triggered by the announcement (and features) of the ASP.NET MVC Framework.

The basic idea is to map (friendly) URLs to the actions of your controllers:

Suppose you want to offer listing of say, cars. You want that the urls show the data that is being queries on the resource identifier, not through the query string (have you read about REST?).

Something like:

www.cardealer.com/listings/ -> can list all or show a search page, up to you
www.cardealer.com/listings/new/ -> shows a nationwide list of new cars
www.cardealer.com/listings/old/ -> shows a nationwide list of second hand cars
www.cardealer.com/listings/new/ford -> new ford cars
www.cardealer.com/listings/new/toyota -> new toyota cars

In order to allow for friendly URLs you’ll have to remove all script mappings from your web site and route all requests to the ASP.NET ISAPI extension. Many people don’t like the idea, stating that “no one would do or want to do such a  thing”. What’s the problem with this approach? I’ve been developing web applications for several years (as part of enterprise applications) and I’ve never experienced the need to serve static content. What’s the use of databases then? However, if you want to serve static content as well, you might follow David Moore’s suggestion to “have the web site and a separate web site to handle static content (images/css/js)”.

The Routing Engine is configured in the Application Start event:

    PatternRule.Build(“bycondition”, “listings/<cond:new|old>”, typeof(SearchController), “View”));

This piece of code tells the engine to route URL-requests such as “/listings/new” or “listings/old” to the SearchController’s View action/method, which expects a parameter called “cond”. The parameter values might be “new” or “old”. The StandardUrlRules utility class allows to easily define generic patterns for all actions/methods of a controller.

The code is available from the MonoRail SVN repository.

Posted by Hartmut Wilms at 23.10.07 20:45


So those enterprise apps of yours have never served CSS or JS or GIF files? :-)

Anyway, another reasonable option would be to put something like an Apache HTTPD in front of your ASP.NET app; presumably people use IIS for this in .NET land?

Posted by: Stefan Tilkov at 24.10.07 07:42

You’re right, as usual :-). As I pointed out in the post, in .NET land you would use a second web site to handle static content.

Posted by: Hartmut Wilms at 27.10.07 20:35