ActionDispatch::Routing::PolymorphicRoutes

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 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_for(@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"

Using with mounted engines

If you use mounted engine, there is a possibility that you will need to use polymorphic_url pointing at engine’s routes. To do that, just pass proxy used to reach engine’s routes as a first argument:

For example:

polymorphic_url([blog, @post]) # it will call blog.post_path(@post) form_for([blog, @post]) # => “/blog/posts/1

Methods

P

polymorphic_path,
polymorphic_url

Instance Public methods

polymorphic_path(record_or_hash_or_array, options = {})

Returns the path component of a URL for the given record. It uses polymorphic_url with :routing_type => :path.

Source: show | on GitHub

     # File actionpack/lib/action_dispatch/routing/polymorphic_routes.rb, line 134
134:       def polymorphic_path(record_or_hash_or_array, options = {})
135:         polymorphic_url(record_or_hash_or_array, options.merge(:routing_type => :path))
136:       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.

Examples

  # 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()