Module: ActionDispatch::Routing::UrlFor

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Included In: `::AbstractController::UrlFor`, `::ActionController::API`, `::ActionController::Base`, `::ActionController::Redirecting`, `::ActionController::UrlFor`, `::ActionDispatch::Integration::Session`, `RouteSet::MountedHelpers`, ActionDispatch::Routing::RoutesProxy, `::ActionView::TestCase::TestController`, Rails::ApplicationController, Rails::InfoController, Rails::MailersController, Rails::WelcomeController
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, `::ActiveSupport::Concern`
Instance Chain: self, `PolymorphicRoutes`
Defined in:	actionpack/lib/action_dispatch/routing/url_for.rb

Overview

In config/routes.rb you define URL-to-controller mappings, but the reverse is also possible: a 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!') %>
# => <a href="/users/new?message=Welcome%21">Click here</a>

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 you still have to provide the :host argument or set the default host that will be used in all mailers using the configuration option config.action_mailer.default_url_options. For more information on url_for in mailers read the ActionMailer#Base documentation.

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"

Class Method Summary

`::ActiveSupport::Concern` - Extended

append_features, class_methods, included

Instance Method Summary

#initialize
#route_for(name, *args)

Allows calling direct or regular named route.
#url_for(options = nil)

Generate a URL based on the options provided, default_url_options and the routes defined in routes.rb.
#url_options

Hook overridden in controller to add request information with default_url_options.
#_routes_context private
#_with_routes(routes) private

`PolymorphicRoutes` - Included

#polymorphic_path	Returns the path component of a URL for the given record.
#polymorphic_url	Constructs a call to a named RESTful route for the given record and returns the resulting URL string.

DSL Calls

included

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 91


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

  include(*_url_for_modules) if respond_to?(:_url_for_modules)
end

Instance Method Details

#_routes_context (private)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 231


def _routes_context # :doc:
  self
end

#_with_routes(routes) (private)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 224


def _with_routes(routes) # :doc:
  old_routes, @_routes = @_routes, routes
  yield
ensure
  @_routes = old_routes
end

#initialize

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 106


def initialize(*)
  @_routes = nil
  super
end

#route_for(name, *args)

Allows calling direct or regular named route.

resources :buckets

direct :recordable do |recording|
  route_for(:bucket, recording.bucket)
end

direct :threadable do |threadable|
  route_for(:recordable, threadable.parent)
end

This maintains the context of the original caller on whether to return a path or full URL, e.g:

threadable_path(threadable)  # => "/buckets/1"
threadable_url(threadable)   # => "http://example.com/buckets/1"

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 212


def route_for(name, *args)
  public_send(:"#{name}_url", *args)
end

#url_for(options = nil)

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 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/”
:script_name - Specifies application path relative to domain root. If provided, prepends application path.

Any other key (:controller, :action, etc.) given to url_for is forwarded to the Routes module.

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'
url_for controller: 'tasks', action: 'testing', host: 'somehost.org', script_name: "/myapp"
# => 'http://somehost.org/myapp/tasks/testing'
url_for controller: 'tasks', action: 'testing', host: 'somehost.org', script_name: "/myapp", only_path: true
# => '/myapp/tasks/testing'

Missing routes keys may be filled in from the current request’s parameters (e.g. :controller, :action, :id and any other parameters that are placed in the path). Given that the current action has been reached through GET /users/1:

url_for(only_path: true)                        # => '/users/1'
url_for(only_path: true, action: 'edit')        # => '/users/1/edit'
url_for(only_path: true, action: 'edit', id: 2) # => '/users/2/edit'

Notice that no :id parameter was provided to the first url_for call and the helper used the one from the route’s path. Any path parameter implicitly used by url_for can always be overwritten like shown on the last url_for calls.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 168


def url_for(options = nil)
  full_url_for(options)
end

#url_options

Hook overridden in controller to add request information with default_url_options. Application logic should not go into url_options.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 114


def url_options
  default_url_options
end

Module: ActionDispatch::Routing::UrlFor

Overview

URL generation from parameters

URL generation for named routes

Class Method Summary

::ActiveSupport::Concern - Extended

Instance Method Summary

PolymorphicRoutes - Included

DSL Calls

included

Instance Method Details

#_routes_context (private)

#_with_routes(routes) (private)

#initialize

#route_for(name, *args)

#url_for(options = nil)

#url_options

`::ActiveSupport::Concern` - Extended

`PolymorphicRoutes` - Included