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::HealthController`, Rails::InfoController, Rails::MailersController, Rails::PwaController, 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 config/routes.rb.

Tip: If you need to generate URLs from your models or some other place, then 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 UrlFor under the hood. And in particular, they use the #url_for method. One can generate the same path as the above example by using the following code:

include ActionDispatch::Routing::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, mailers also include UrlFor. So within mailers, you can use url_for. However, mailers cannot access incoming web requests in order to derive hostname information, so you have to provide the :host option or set the default host using default_url_options. For more information on url_for in mailers see 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

class_methods	Define class methods from given block.
included	Evaluate given block in context of base class, so that you can write class macros here.
prepended	Evaluate given block in context of base class, so that you can write class macros here.

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 config/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 96


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 239


def _routes_context # :doc:
  self
end

#_with_routes(routes) (private)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/url_for.rb', line 232


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 111


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 222


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 config/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.
:params - The query parameters to be appended to the path.
:path_params - The query parameters that will only be used for the named dynamic segments of path. If unused, they will be discarded.
: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 178


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 118


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