Module: ActionDispatch::Routing::UrlFor

Extended by:
ActiveSupport::Concern
Includes:
PolymorphicRoutes
Included in:
AbstractController::UrlFor, Integration::Session, RouteSet::MountedHelpers, RoutesProxy
Defined in:
lib/action_dispatch/routing/url_for.rb

Overview

# Action Dispatch Routing UrlFor

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 ActionDispatch::Routing::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 ActionDispatch::Routing::UrlFor under the hood. And in particular, they use the ActionDispatch::Routing::UrlFor#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 ActionDispatch::Routing::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"

Instance Method Summary collapse

Methods included from PolymorphicRoutes

#polymorphic_path, #polymorphic_url

Instance Method Details

#full_url_for(options = nil) ⇒ Object

:nodoc:



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# File 'lib/action_dispatch/routing/url_for.rb', line 182

def full_url_for(options = nil) # :nodoc:
  case options
  when nil
    _routes.url_for(url_options.symbolize_keys)
  when Hash, ActionController::Parameters
    route_name = options.delete :use_route
    merged_url_options = options.to_h.symbolize_keys.reverse_merge!(url_options)
    _routes.url_for(merged_url_options, route_name)
  when String
    options
  when Symbol
    HelperMethodBuilder.url.handle_string_call self, options
  when Array
    components = options.dup
    polymorphic_url(components, components.extract_options!)
  when Class
    HelperMethodBuilder.url.handle_class_call self, options
  else
    HelperMethodBuilder.url.handle_model_call self, options
  end
end

#initialize ⇒ Object 



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# File 'lib/action_dispatch/routing/url_for.rb', line 111

def initialize(...)
  @_routes = nil
  super
end

#route_for(name, *args) ⇒ Object

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"



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# File 'lib/action_dispatch/routing/url_for.rb', line 222

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

#url_for(options = nil) ⇒ Object

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 `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.

  • ‘: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.



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# File 'lib/action_dispatch/routing/url_for.rb', line 178

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

#url_options ⇒ Object

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



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# File 'lib/action_dispatch/routing/url_for.rb', line 118

def url_options
  default_url_options
end