How do we identify parameters in a dynamic URL?

Question

We are building a Rails CMS where a blog or news listing can appear anywhere in the site tree. This means that any page knows their type based on a database field - eg: a p

Answer 1

You can use route globbing and constraints to match a proper pattern.

# Rails 2.x
map.connect "*path/:year/:month", 
             :constraints => {:year => /\d{4}/, :month => /0[1-9]|1[0-2]/ },
             :controller => :pages, :action => :month_archive

# Rails 3.x
match "*path/:year/:month" => "pages#month_archive", 
             :constraints => {:year => /\d{4}/, :month => /0[1-9]|1[0-2]/ }

This will match /dogs/snoopy-news/2010/11 and pass :path => "dogs/snoopy-news", :year => "2010", :month => "11" in the params hash. It will match all routes that have a year and a month as the last two segments, regardless of how many segments come beforehand. And it will reject any route that doesn't match a proper year and month in the last two segments. What you do with the :path parameter is up to you in the controller.