Module: ActionController::PolymorphicRoutes

Included in:
Routing::Helpers, ActionView::TestCase
Defined in:
lib/action_controller/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 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"

Instance Method Summary collapse

Instance Method Details

#polymorphic_path(record_or_hash_or_array, options = {}) ⇒ Object

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



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# File 'lib/action_controller/polymorphic_routes.rb', line 106

def polymorphic_path(record_or_hash_or_array, options = {})
  options[:routing_type] = :path
  polymorphic_url(record_or_hash_or_array, options)
end

#polymorphic_url(record_or_hash_or_array, options = {}) ⇒ Object

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()



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# File 'lib/action_controller/polymorphic_routes.rb', line 71

def polymorphic_url(record_or_hash_or_array, options = {})
  if record_or_hash_or_array.kind_of?(Array)
    record_or_hash_or_array = record_or_hash_or_array.dup
  end

  record    = extract_record(record_or_hash_or_array)
  format    = extract_format(record_or_hash_or_array, options)
  namespace = extract_namespace(record_or_hash_or_array)
  
  args = case record_or_hash_or_array
    when Hash;  [ record_or_hash_or_array ]
    when Array; record_or_hash_or_array.dup
    else        [ record_or_hash_or_array ]
  end

  args << format if format

  inflection =
    case
    when options[:action].to_s == "new"
      args.pop
      :singular
    when record.respond_to?(:new_record?) && record.new_record?
      args.pop
      :plural
    else
      :singular
    end
  
  named_route = build_named_route_call(record_or_hash_or_array, namespace, inflection, options)
  send!(named_route, *args)
end