module ActionDispatch
module Routing
# In config/routes.rb you define 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 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. In general, this module should not be included on its own,
# as it is usually included by url_helpers (as in Rails.application.routes.url_helpers).
#
# == 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!') %>
# # => "/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')
# # => "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 that'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
# config/routes.rb:
#
# 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 Rails.application.routes.url_helpers in your class:
#
# class User < ActiveRecord::Base
# include Rails.application.routes.url_helpers
#
# def base_uri
# user_path(self)
# end
# end
#
# User.find(1).base_uri # => "/users/1"
#
module UrlFor
extend ActiveSupport::Concern
include PolymorphicRoutes
included do
unless method_defined?(:default_url_options)
# 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_writer :default_url_options
end
self.default_url_options = {}
end
end
def initialize(*)
@_routes = nil
super
end
# Hook overriden in controller to add request information
# with `default_url_options`. Application logic should not
# go into url_options.
def url_options
default_url_options
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+.
# * :subdomain - Specifies the subdomain of the link, using the +tld_length+
# to split the subdomain from the host.
# If false, removes all subdomains from the host part of the link.
# * :domain - Specifies the domain of the link, using the +tld_length+
# to split the domain from the host.
# * :tld_length - Number of labels the TLD id composed of, only used if
# :subdomain or :domain are supplied. Defaults to
# ActionDispatch::Http::URL.tld_length, which in turn defaults to 1.
# * :port - Optionally specify the port to connect to.
# * :anchor - An anchor name to be appended to the path.
# * :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 = nil)
case options
when nil
_routes.url_for(url_options.symbolize_keys)
when Hash
_routes.url_for(options.symbolize_keys.reverse_merge!(url_options))
when String
options
else
polymorphic_url(options)
end
end
protected
def optimize_routes_generation?
return @_optimized_routes if defined?(@_optimized_routes)
@_optimized_routes = _routes.optimize_routes_generation? && default_url_options.empty?
end
def _with_routes(routes)
old_routes, @_routes = @_routes, routes
yield
ensure
@_routes = old_routes
end
def _routes_context
self
end
end
end
end