module ActionDispatch module Routing # In routes.rb one defines URL-to-controller mappings, but the reverse # is also possible: an URL can be generated from one of your routing definitions. # URL generation functionality is centralized in this module. # # See ActionDispatch::Routing and ActionController::Resources for general # information about routing and routes.rb. # # Tip: If you need to generate URLs from your models or some other place, # then ActionController::UrlFor is what you're looking for. Read on for # an introduction. # # == URL generation from parameters # # As you may know, some functions - such as ActionController::Base#url_for # and ActionView::Helpers::UrlHelper#link_to, can generate URLs given a set # of parameters. For example, you've probably had the chance to write code # like this in one of your views: # # <%= link_to('Click here', :controller => 'users', # :action => 'new', :message => 'Welcome!') %> # # #=> Generates a link to: /users/new?message=Welcome%21 # # link_to, and all other functions that require URL generation functionality, # actually use ActionController::UrlFor under the hood. And in particular, # they use the ActionController::UrlFor#url_for method. One can generate # the same path as the above example by using the following code: # # include UrlFor # url_for(:controller => 'users', # :action => 'new', # :message => 'Welcome!', # :only_path => true) # # => "/users/new?message=Welcome%21" # # Notice the :only_path => true part. This is because UrlFor has no # information about the website hostname that your Rails app is serving. So if you # want to include the hostname as well, then you must also pass the :host # argument: # # include UrlFor # url_for(:controller => 'users', # :action => 'new', # :message => 'Welcome!', # :host => 'www.example.com') # Changed this. # # => "http://www.example.com/users/new?message=Welcome%21" # # By default, all controllers and views have access to a special version of url_for, # that already knows what the current hostname is. So if you use url_for in your # controllers or your views, then you don't need to explicitly pass the :host # argument. # # For convenience reasons, mailers provide a shortcut for ActionController::UrlFor#url_for. # So within mailers, you only have to type 'url_for' instead of 'ActionController::UrlFor#url_for' # in full. However, mailers don't have hostname information, and what's why you'll still # have to specify the :host argument when generating URLs in mailers. # # # == URL generation for named routes # # UrlFor also allows one to access methods that have been auto-generated from # named routes. For example, suppose that you have a 'users' resource in your # routes.rb: # # map.resources :users # # This generates, among other things, the method users_path. By default, # this method is accessible from your controllers, views and mailers. If you need # to access this auto-generated method from other places (such as a model), then # you can do that by including ActionController::UrlFor in your class: # # class User < ActiveRecord::Base # include ActionController::UrlFor # # def base_uri # user_path(self) # end # end # # User.find(1).base_uri # => "/users/1" # module UrlFor extend ActiveSupport::Concern included do # ActionDispatch::Routing::Routes.install_helpers(self) # Including in a class uses an inheritable hash. Modules get a plain hash. if respond_to?(:class_attribute) class_attribute :default_url_options else mattr_accessor :default_url_options end self.default_url_options = {} end # Overwrite to implement a number of default options that all url_for-based methods will use. The default options should come in # the form of a hash, just like the one you would use for url_for directly. Example: # # def default_url_options(options) # { :project => @project.active? ? @project.url_name : "unknown" } # end # # As you can infer from the example, this is mostly useful for situations where you want to centralize dynamic decisions about the # urls as they stem from the business domain. Please note that any individual url_for call can always override the defaults set # by this method. def default_url_options(options = nil) # ROUTES TODO: This should probably be an instance method self.class.default_url_options end def rewrite_options(options) #:nodoc: if options.delete(:use_defaults) != false && (defaults = default_url_options(options)) defaults.merge(options) else options end end # Generate a url based on the options provided, default_url_options and the # routes defined in routes.rb. The following options are supported: # # * :only_path - If true, the relative url is returned. Defaults to +false+. # * :protocol - The protocol to connect to. Defaults to 'http'. # * :host - Specifies the host the link should be targeted at. # If :only_path is false, this option must be # provided either explicitly, or via +default_url_options+. # * :port - Optionally specify the port to connect to. # * :anchor - An anchor name to be appended to the path. # * :skip_relative_url_root - If true, the url is not constructed using the # +relative_url_root+ set in ActionController::Base.relative_url_root. # * :trailing_slash - If true, adds a trailing slash, as in "/archive/2009/" # # Any other key (:controller, :action, etc.) given to # +url_for+ is forwarded to the Routes module. # # Examples: # # url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :port=>'8080' # => 'http://somehost.org:8080/tasks/testing' # url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :anchor => 'ok', :only_path => true # => '/tasks/testing#ok' # url_for :controller => 'tasks', :action => 'testing', :trailing_slash=>true # => 'http://somehost.org/tasks/testing/' # url_for :controller => 'tasks', :action => 'testing', :host=>'somehost.org', :number => '33' # => 'http://somehost.org/tasks/testing?number=33' def url_for(options = {}) options ||= {} case options when String options when Hash _url_rewriter.rewrite(_router, rewrite_options(options)) else polymorphic_url(options) end end protected # ROUTES TODO: Figure out why _url_rewriter is sometimes the class and # sometimes an instance. def _url_rewriter ActionController::UrlRewriter end end end end