Module: ActionDispatch::Routing::PolymorphicRoutes

Relationships & Source Files
Namespace Children
Classes: `HelperMethodBuilder`
Extension / Inclusion / Inheritance Descendants
Included In: `::AbstractController::UrlFor`, `::ActionController::API`, `::ActionController::Base`, `::ActionController::Redirecting`, `::ActionController::UrlFor`, `::ActionDispatch::Integration::Session`, `::ActionDispatch::IntegrationTest`, `RouteSet::MountedHelpers`, `RoutesProxy`, `UrlFor`, `::ActionView::TestCase`, `::ActionView::TestCase::Behavior`, `::ActionView::TestCase::TestController`, `::Rails::ApplicationController`, `::Rails::HealthController`, `::Rails::InfoController`, `::Rails::MailersController`, `::Rails::PwaController`, `::Rails::WelcomeController`
Defined in:	actionpack/lib/action_dispatch/routing/polymorphic_routes.rb

Overview

Polymorphic URL helpers are methods for smart resolution to a named route call when given an Active Record model instance. They are to be used in combination with ActionController::Resources.

These methods are useful when you want to generate the correct URL or path to a RESTful resource without having to know the exact type of the record in question.

Nested resources and/or namespaces are also supported, as illustrated in the example:

polymorphic_url([:admin, @article, @comment])

results in:

admin_article_comment_url(@article, @comment)

Usage within the framework

Polymorphic URL helpers are used in a number of places throughout the ::Rails framework:

url_for, so you can use it with a record as the argument, e.g. url_for(@article);
::ActionView::Helpers::FormHelper uses #polymorphic_path, so you can write form_with(model: @article) without having to specify :url parameter for the form action;
redirect_to (which, in fact, uses url_for) so you can write redirect_to(post) in your controllers;
::ActionView::Helpers::AtomFeedHelper, so you don't have to explicitly specify URLs for feed entries.

Prefixed polymorphic helpers

In addition to #polymorphic_url and #polymorphic_path methods, a number of prefixed helpers are available as a shorthand to action: "..." in options. Those are:

edit_polymorphic_url, edit_polymorphic_path
new_polymorphic_url, new_polymorphic_path

Example usage:

edit_polymorphic_path(@post)           # => "/posts/1/edit"
polymorphic_path(@post, format: :pdf)  # => "/posts/1.pdf"

Usage with mounted engines

If you are using a mounted engine and you need to use a polymorphic_url pointing at the engine's routes, pass in the engine's route proxy as the first argument to the method. For example:

polymorphic_url([blog, @post])  # calls blog.post_path(@post)
form_with(model: [blog, @post]) # => "/blog/posts/1"

Instance Method Summary

#polymorphic_path(record_or_hash_or_array, options = {})

Returns the path component of a URL for the given record.
#polymorphic_url(record_or_hash_or_array, options = {})

Constructs a call to a named RESTful route for the given record and returns the resulting URL string.
#polymorphic_mapping(record) private
#polymorphic_path_for_action(action, record_or_hash, options) private
#polymorphic_url_for_action(action, record_or_hash, options) private

Instance Method Details

#polymorphic_mapping(record) (private)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/polymorphic_routes.rb', line 177


def polymorphic_mapping(record)
  if record.respond_to?(:to_model)
    _routes.polymorphic_mappings[record.to_model.model_name.name]
  else
    _routes.polymorphic_mappings[record.class.name]
  end
end

#polymorphic_path(record_or_hash_or_array, options = {})

Returns the path component of a URL for the given record.

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/polymorphic_routes.rb', line 133


def polymorphic_path(record_or_hash_or_array, options = {})
  if Hash === record_or_hash_or_array
    options = record_or_hash_or_array.merge(options)
    record  = options.delete :id
    return polymorphic_path record, options
  end

  if mapping = polymorphic_mapping(record_or_hash_or_array)
    return mapping.call(self, [record_or_hash_or_array, options], true)
  end

  opts   = options.dup
  action = opts.delete :action
  type   = :path

  HelperMethodBuilder.polymorphic_method self,
                                         record_or_hash_or_array,
                                         action,
                                         type,
                                         opts
end

#polymorphic_path_for_action(action, record_or_hash, options) (private)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/polymorphic_routes.rb', line 173


def polymorphic_path_for_action(action, record_or_hash, options)
  polymorphic_path(record_or_hash, options.merge(action: action))
end

#polymorphic_url(record_or_hash_or_array, options = {})

Constructs a call to a named RESTful route for the given record and returns the resulting URL string. For example:

# calls post_url(post)
polymorphic_url(post) # => "http://example.com/posts/1"
polymorphic_url([blog, post]) # => "http://example.com/blogs/1/posts/1"
polymorphic_url([:admin, blog, post]) # => "http://example.com/admin/blogs/1/posts/1"
polymorphic_url([user, :blog, post]) # => "http://example.com/users/1/blog/posts/1"
polymorphic_url(Comment) # => "http://example.com/comments"

Options

:action - Specifies the action prefix for the named route: :new or :edit. Default is no prefix.
:routing_type - Allowed values are :path or :url. Default is :url.

Also includes all the options from url_for. These include such things as :anchor or :trailing_slash. Example usage is given below:

polymorphic_url([blog, post], anchor: 'my_anchor')
  # => "http://example.com/blogs/1/posts/1#my_anchor"
polymorphic_url([blog, post], anchor: 'my_anchor', script_name: "/my_app")
  # => "http://example.com/my_app/blogs/1/posts/1#my_anchor"

For all of these options, see the documentation for url_for.

Functionality

# an Article record
polymorphic_url(record)  # same as article_url(record)

# a Comment record
polymorphic_url(record)  # same as comment_url(record)

# it recognizes new records and maps to the collection
record = Comment.new
polymorphic_url(record)  # same as comments_url()

# the class of a record will also map to the collection
polymorphic_url(Comment) # same as comments_url()

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/polymorphic_routes.rb', line 110


def polymorphic_url(record_or_hash_or_array, options = {})
  if Hash === record_or_hash_or_array
    options = record_or_hash_or_array.merge(options)
    record  = options.delete :id
    return polymorphic_url record, options
  end

  if mapping = polymorphic_mapping(record_or_hash_or_array)
    return mapping.call(self, [record_or_hash_or_array, options], false)
  end

  opts   = options.dup
  action = opts.delete :action
  type   = opts.delete(:routing_type) || :url

  HelperMethodBuilder.polymorphic_method self,
                                         record_or_hash_or_array,
                                         action,
                                         type,
                                         opts
end

#polymorphic_url_for_action(action, record_or_hash, options) (private)

[ GitHub ]

# File 'actionpack/lib/action_dispatch/routing/polymorphic_routes.rb', line 169


def polymorphic_url_for_action(action, record_or_hash, options)
  polymorphic_url(record_or_hash, options.merge(action: action))
end