The routes.rb File
Routes are defined in the file config/routes.rb. This file is created when you create your application. It comes with a few routes already written. In most cases, you'll want to change and/or add to the routes defined in the file.
As generated by Rails, routes.rb looks like this:
ActionController::Routing::Routes.draw do |map| # The priority is based upon order of creation: first created -> highest priority. # Sample of regular route: # map.connect 'products/:id', :controller => 'catalog', :action => 'view' # Keep in mind you can assign values other than :controller and :action # Sample of named route: # map.purchase 'products/:id/purchase', :controller => 'catalog', :action => 'purchase' # This route can be invoked with purchase_url(:id => product.id) # You can have the root of your site routed by hooking up '' # -- just remember to delete public/index.html. # map.connect '', :controller => "welcome" # Allow downloading Web Service WSDL as a file with an extension # instead of a file named 'wsdl' map.connect ':controller/service.wsdl', :action => 'wsdl' # Install the default route as the lowest priority. map.connect ':controller/:action/:id.:format' map.connect ':controller/:action/:id' end
The whole thing consists of a single call to the method ActionController::Routing::Routes.draw. That method takes a block; and everything from the second line of the file to the second-to-last line is that block.
Inside the block, you have access to a variable called map. This variable is an object of the class ActionController::Routing::RouteSet::Mapper. It's what gives you leverage on the routing system: You define routing rules by calling methods on your mapper object. In the default routes.rb file, you see several calls to map.connect. Each such call (at least, those that aren't commented out) creates a new route by registering it with the routing system. The routing system has to find a pattern match for a URL it's trying to recognize, or a parameters match for a URL it's trying to generate. It does this by going through the rules -- the routes -- in the order in which they're defined; that is, the order in which they appear in routes.rb. If a given route fails to match, the matching routine falls through to the next one. As soon as any route succeeds in providing the necessary match, the search ends.
