The routing module provides URL rewriting in native Ruby. It‘s a way to redirect incoming requests to controllers and actions. This replaces mod_rewrite rules. Best of all, RailsRouting works with any web server. Routes are defined in config/routes.rb.

Consider the following route, installed by Rails when you generate your application:

  map.connect ':controller/:action/:id'

This route states that it expects requests to consist of a :controller followed by an :action that in turn is fed some :id.

Suppose you get an incoming request for /blog/edit/22, you‘ll end up with:

  params = { :controller => 'blog',
             :action     => 'edit',
             :id         => '22'

Think of creating routes as drawing a map for your requests. The map tells them where to go based on some predefined pattern:

  ActionController::Routing::Routes.draw do |map|
    Pattern 1 tells some request to go to one place
    Pattern 2 tell them to go to another

The following symbols are special:

  :controller maps to your controller name
  :action     maps to an action with your controllers

Other names simply map to a parameter as in the case of :id.

Route priority

Not all routes are created equally. Routes have priority defined by the order of appearance of the routes in the config/routes.rb file. The priority goes from top to bottom. The last route in that file is at the lowest priority and will be applied last. If no route matches, 404 is returned.

Within blocks, the empty pattern is at the highest priority. In practice this works out nicely:

  ActionController::Routing::Routes.draw do |map|
    map.with_options :controller => 'blog' do |blog| '',  :action => 'list'
    map.connect ':controller/:action/:view'

In this case, invoking blog controller (with an URL like ’/blog/’) without parameters will activate the ‘list’ action by default.

Defaults routes and default parameters

Setting a default route is straightforward in Rails - you simply append a Hash at the end of your mapping to set any default parameters.


  ActionController::Routing:Routes.draw do |map|
    map.connect ':controller/:action/:id', :controller => 'blog'

This sets up blog as the default controller if no other is specified. This means visiting ’/’ would invoke the blog controller.

More formally, you can include arbitrary parameters in the route, thus:

  map.connect ':controller/:action/:id', :action => 'show', :page => 'Dashboard'

This will pass the :page parameter to all incoming requests that match this route.

Note: The default routes, as provided by the Rails generator, make all actions in every controller accessible via GET requests. You should consider removing them or commenting them out if you‘re using named routes and resources.

Named routes

Routes can be named with the syntax map.name_of_route options, allowing for easy reference within your source as name_of_route_url for the full URL and name_of_route_path for the URI path.


  # In routes.rb
  map.login 'login', :controller => 'accounts', :action => 'login'

  # With render, redirect_to, tests, etc.
  redirect_to login_url

Arguments can be passed as well.

  redirect_to show_item_path(:id => 25)

Use map.root as a shorthand to name a route for the root path "".

  # In routes.rb
  map.root :controller => 'blogs'

  # would recognize as
  params = { :controller => 'blogs', :action => 'index' }

  # and provide these named routes
  root_url   # => ''
  root_path  # => ''

You can also specify an already-defined named route in your map.root call:

  # In routes.rb
  map.new_session :controller => 'sessions', :action => 'new'
  map.root :new_session

Note: when using with_options, the route is simply named after the method you call on the block parameter rather than map.

  # In routes.rb
  map.with_options :controller => 'blog' do |blog|    '',            :action  => 'list'
    blog.delete  'delete/:id',  :action  => 'delete',
    blog.edit    'edit/:id',    :action  => 'edit'

  # provides named routes for show, delete, and edit
  link_to @article.title, show_path(:id =>

Pretty URLs

Routes can generate pretty URLs. For example:

  map.connect 'articles/:year/:month/:day',
              :controller => 'articles',
              :action     => 'find_by_date',
              :year       => /\d{4}/,
              :month      => /\d{1,2}/,
              :day        => /\d{1,2}/

Using the route above, the URL "localhost:3000/articles/2005/11/06" maps to

  params = {:year => '2005', :month => '11', :day => '06'}

Regular Expressions and parameters

You can specify a regular expression to define a format for a parameter.

  map.geocode 'geocode/:postalcode', :controller => 'geocode',
              :action => 'show', :postalcode => /\d{5}(-\d{4})?/

or, more formally:

  map.geocode 'geocode/:postalcode', :controller => 'geocode',
              :action => 'show', :requirements => { :postalcode => /\d{5}(-\d{4})?/ }

Formats can include the ‘ignorecase’ and ‘extended syntax’ regular expression modifiers:

  map.geocode 'geocode/:postalcode', :controller => 'geocode',
              :action => 'show', :postalcode => /hx\d\d\s\d[a-z]{2}/i

  map.geocode 'geocode/:postalcode', :controller => 'geocode',
              :action => 'show',:requirements => {
                :postalcode => /# Postcode format
                                \d{5} #Prefix
                                (-\d{4})? #Suffix

Using the multiline match modifier will raise an ArgumentError. Encoding regular expression modifiers are silently ignored. The match will always use the default encoding or ASCII.

Route globbing

Specifying *[string] as part of a rule like:

  map.connect '*path' , :controller => 'blog' , :action => 'unrecognized?'

will glob all remaining parts of the route that were not recognized earlier. The globbed values are in params[:path] as an array of path segments.

Route conditions

With conditions you can define restrictions on routes. Currently the only valid condition is :method.

  • :method - Allows you to specify which method can access the route. Possible values are :post, :get, :put, :delete and :any. The default value is :any, :any means that any method can access the route.


  map.connect 'post/:id', :controller => 'posts', :action => 'show',
              :conditions => { :method => :get }
  map.connect 'post/:id', :controller => 'posts', :action => 'create_comment',
              :conditions => { :method => :post }

Now, if you POST to /posts/:id, it will route to the create_comment action. A GET on the same URL will route to the show action.

Reloading routes

You can reload routes if you feel you must:


This will clear all named routes and reload routes.rb if the file has been modified from last load. To absolutely force reloading, use reload!.

Testing Routes

The two main methods for testing your routes:


  def test_movie_route_properly_splits
   opts = {:controller => "plugin", :action => "checkout", :id => "2"}
   assert_routing "plugin/checkout/2", opts

assert_routing lets you test whether or not the route properly resolves into options.


  def test_route_has_options
   opts = {:controller => "plugin", :action => "show", :id => "12"}
   assert_recognizes opts, "/plugins/show/12"

Note the subtle difference between the two: assert_routing tests that a URL fits options while assert_recognizes tests that a URL breaks into parameters properly.

In tests you can simply pass the URL or named route to get or post.

  def send_to_jail
    get '/jail'
    assert_response :success
    assert_template "jail/front"

  def goes_to_login
    get login_url

View a list of all your routes

Run rake routes.

Classes and Modules
Module ActionController::Routing::Helpers
Module ActionController::Routing::Optimisation
Class ActionController::Routing::OptionalFormatSegment
SEPARATORS = %w( / . ? )
HTTP_METHODS = [:get, :head, :post, :put, :delete, :options]
ALLOWED_REQUIREMENTS_FOR_OPTIMISATION = [:controller, :action].to_set
Routes =
Public Class methods
controller_relative_to(controller, previous)

Returns a controller path for a new controller based on a previous controller path. Handles 4 scenarios:

  • stay in the previous controller:
      controller_relative_to( nil, "groups/discussion" ) # => "groups/discussion"
  • stay in the previous namespace:
      controller_relative_to( "posts", "groups/discussion" ) # => "groups/posts"
  • forced move to the root namespace:
      controller_relative_to( "/posts", "groups/discussion" ) # => "posts"
  • previous namespace is root:
      controller_relative_to( "posts", "anything_with_no_slashes" ) # =>"posts"
     # File actionpack/lib/action_controller/routing.rb, line 366
366:       def controller_relative_to(controller, previous)
367:         if controller.nil?           then previous
368:         elsif controller[0] == ?/    then controller[1..-1]
369:         elsif %r{^(.*)/} =~ previous then "#{$1}/#{controller}"
370:         else controller
371:         end
372:       end

Returns an array of paths, cleaned of double-slashes and relative path references.

  • "\\" and "//" become "\" or "/".
  • "/foo/bar/../config" becomes "/foo/config".

The returned array is sorted by length, descending.

     # File actionpack/lib/action_controller/routing.rb, line 302
302:       def normalize_paths(paths)
303:         # do the hokey-pokey of path normalization...
304:         paths = paths.collect do |path|
305:           path = path.
306:             gsub("//", "/").           # replace double / chars with a single
307:             gsub("\\\\", "\\").        # replace double \ chars with a single
308:             gsub(%r{(.)[\\/]$}, '\1')  # drop final / or \ if path ends with it
310:           # eliminate .. paths where possible
311:           re = %r{[^/\\]+[/\\]\.\.[/\\]}
312:           path.gsub!(re, "") while path.match(re)
313:           path
314:         end
316:         # start with longest path, first
317:         paths = paths.uniq.sort_by { |path| - path.length }
318:       end

Returns the array of controller names currently available to ActionController::Routing.

     # File actionpack/lib/action_controller/routing.rb, line 321
321:       def possible_controllers
322:         unless @possible_controllers
323:           @possible_controllers = []
325:           paths = { |path| && path != "." }
327:           seen_paths = {|h, k| h[k] = true; false}
328:           normalize_paths(paths).each do |load_path|
329:             Dir["#{load_path}/**/*_controller.rb"].collect do |path|
330:               next if seen_paths[path.gsub(%r{^\.[/\\]}, "")]
332:               controller_name = path[(load_path.length + 1)..-1]
334:               controller_name.gsub!(/_controller\.rb\Z/, '')
335:               @possible_controllers << controller_name
336:             end
337:           end
339:           # remove duplicates
340:           @possible_controllers.uniq!
341:         end
342:         @possible_controllers
343:       end

Replaces the internal list of controllers available to ActionController::Routing with the passed argument.

  ActionController::Routing.use_controllers!([ "posts", "comments", "admin/comments" ])
     # File actionpack/lib/action_controller/routing.rb, line 347
347:       def use_controllers!(controller_names)
348:         @possible_controllers = controller_names
349:       end
with_controllers(names) {|| ...}

Expects an array of controller names as the first argument. Executes the passed block with only the named controllers named available. This method is used in internal Rails testing.

     # File actionpack/lib/action_controller/routing.rb, line 290
290:       def with_controllers(names)
291:         prior_controllers = @possible_controllers
292:         use_controllers! names
293:         yield
294:       ensure
295:         use_controllers! prior_controllers
296:       end
Public Instance methods

Ensures that routes are reloaded when Rails inflections are updated.

     # File actionpack/lib/action_controller/routing.rb, line 379
379:       def inflections_with_route_reloading(&block)
380:         (inflections_without_route_reloading(&block)).tap {
381:           ActionController::Routing::Routes.reload! if block_given?
382:         }
383:       end