Routing
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 Rails’ Routing works with any web server. Routes are defined in routes.rb in your RAILS_ROOT/config directory.
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 turns is fed by 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 ... end
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 routes.rb file. The priority goes from top to bottom. The last route in that file is at the lowest priority will be applied last. If no route matches, 404 is returned.
Within blocks, the empty pattern goes first i.e. is at the highest priority. In practice this works out nicely:
ActionController::Routing::Routes.draw do |map| map.with_options :controller => 'blog' do |blog| blog.show '', :action => 'list' end map.connect ':controller/:action/:view end
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 because by appending a Hash to the end of your mapping you can set default parameters.
Example:
ActionController::Routing:Routes.draw do |map| map.connect ':controller/:action/:id', :controller => 'blog' end
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 define defaults in a route with the +:defaults+ key.
map.connect ':controller/:id/:action', :action => 'show', :defaults => { :page => 'Dashboard' }
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.
Example:
# 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 http://www.example.com/ as params = { :controller => 'blogs', :action => 'index' } # and provide these named routes root_url # => 'http://www.example.com/' root_path # => ''
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| blog.show '', :action => 'list' blog.delete 'delete/:id', :action => 'delete', blog.edit 'edit/:id', :action => 'edit' end # provides named routes for show, delete, and edit link_to @article.title, show_path(:id => @article.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 below maps to: # params = {:year => '2005', :month => '11', :day => '06'} # http://localhost:3000/articles/2005/11/06
Regular Expressions and parameters
You can specify a reqular 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})?/ }
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. This idiom must appear at the end of the path. The globbed values are in params[:path] in this case.
Reloading routes
You can reload routes if you feel you must:
Action::Controller::Routes.reload
This will clear all named routes and reload routes.rb
Testing Routes
The two main methods for testing your routes:
assert_routing
def test_movie_route_properly_splits opts = {:controller => "plugin", :action => "checkout", :id => "2"} assert_routing "plugin/checkout/2", opts end
assert_routing lets you test whether or not the route properly resolves into options.
assert_recognizes
def test_route_has_options opts = {:controller => "plugin", :action => "show", :id => "12"} assert_recognizes opts, "/plugins/show/12" end
Note the subtle difference between the two: assert_routing tests that an URL fits options while assert_recognizes tests that an 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" end def goes_to_login get login_url #... end
SEPARATORS | = | %w( / ; . , ? ) |
Routes | = | RouteSet.new |
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# File vendor/rails/actionpack/lib/action_controller/routing.rb, line 310 310: def controller_relative_to(controller, previous) 311: if controller.nil? then previous 312: elsif controller[0] == ?/ then controller[1..-1] 313: elsif %r{^(.*)/} =~ previous then "#{$1}/#{controller}" 314: else controller 315: end 316: end
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# File vendor/rails/actionpack/lib/action_controller/routing.rb, line 264 264: def normalize_paths(paths) 265: # do the hokey-pokey of path normalization... 266: paths = paths.collect do |path| 267: path = path. 268: gsub("//", "/"). # replace double / chars with a single 269: gsub("\\\\", "\\"). # replace double \ chars with a single 270: gsub(%r{(.)[\\/]$}, '\1') # drop final / or \ if path ends with it 271: 272: # eliminate .. paths where possible 273: re = %r{\w+[/\\]\.\.[/\\]} 274: path.gsub!(%r{\w+[/\\]\.\.[/\\]}, "") while path.match(re) 275: path 276: end 277: 278: # start with longest path, first 279: paths = paths.uniq.sort_by { |path| - path.length } 280: end
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# File vendor/rails/actionpack/lib/action_controller/routing.rb, line 282 282: def possible_controllers 283: unless @possible_controllers 284: @possible_controllers = [] 285: 286: paths = controller_paths.select { |path| File.directory?(path) && path != "." } 287: 288: seen_paths = Hash.new {|h, k| h[k] = true; false} 289: normalize_paths(paths).each do |load_path| 290: Dir["#{load_path}/**/*_controller.rb"].collect do |path| 291: next if seen_paths[path.gsub(%r{^\.[/\\]}, "")] 292: 293: controller_name = path[(load_path.length + 1)..-1] 294: 295: controller_name.gsub!(/_controller\.rb\Z/, '') 296: @possible_controllers << controller_name 297: end 298: end 299: 300: # remove duplicates 301: @possible_controllers.uniq! 302: end 303: @possible_controllers 304: end
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# File vendor/rails/actionpack/lib/action_controller/routing.rb, line 306 306: def use_controllers!(controller_names) 307: @possible_controllers = controller_names 308: end
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# File vendor/rails/actionpack/lib/action_controller/routing.rb, line 256 256: def with_controllers(names) 257: prior_controllers = @possible_controllers 258: use_controllers! names 259: yield 260: ensure 261: use_controllers! prior_controllers 262: end