Module ActionController::PolymorphicRoutes
In: vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb

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
  • formatted_polymorphic_url, formatted_polymorphic_path

Example usage:

  edit_polymorphic_path(@post)              # => "/posts/1/edit"
  formatted_polymorphic_path([@post, :pdf]) # => "/posts/1.pdf"

Methods

Public Instance methods

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

[Source]

     # File vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb, line 106
106:     def polymorphic_path(record_or_hash_or_array, options = {})
107:       options[:routing_type] = :path
108:       polymorphic_url(record_or_hash_or_array, options)
109:     end

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"

Options

  • :action - Specifies the action prefix for the named route: :new, :edit, or :formatted. 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()

[Source]

     # File vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb, line 71
 71:     def polymorphic_url(record_or_hash_or_array, options = {})
 72:       if record_or_hash_or_array.kind_of?(Array)
 73:         record_or_hash_or_array = record_or_hash_or_array.dup
 74:       end
 75: 
 76:       record    = extract_record(record_or_hash_or_array)
 77:       format    = extract_format(record_or_hash_or_array, options)
 78:       namespace = extract_namespace(record_or_hash_or_array)
 79:       
 80:       args = case record_or_hash_or_array
 81:         when Hash;  [ record_or_hash_or_array ]
 82:         when Array; record_or_hash_or_array.dup
 83:         else        [ record_or_hash_or_array ]
 84:       end
 85: 
 86:       args << format if format
 87: 
 88:       inflection =
 89:         case
 90:         when options[:action].to_s == "new"
 91:           args.pop
 92:           :singular
 93:         when record.respond_to?(:new_record?) && record.new_record?
 94:           args.pop
 95:           :plural
 96:         else
 97:           :singular
 98:         end
 99:       
100:       named_route = build_named_route_call(record_or_hash_or_array, namespace, inflection, options)
101:       send!(named_route, *args)
102:     end

[Validate]