Module: ActionController::Resources

Defined in:
lib/action_controller/resources.rb

Defined Under Namespace

Classes: Resource

Instance Method Summary collapse

Instance Method Details

#resources(*entities, &block) ⇒ Object

Creates named routes for implementing verb-oriented controllers. This is useful for implementing REST API’s, where a single resource has different behavior based on the HTTP verb (method) used to access it.

Example:

map.resources :messages 

class MessagesController < ActionController::Base
  # GET messages_url
  def index
    # return all messages
  end

  # GET new_message_url
  def new
    # return an HTML form for describing a new message
  end

  # POST messages_url
  def create
    # create a new message
  end

  # GET message_url(:id => 1)
  def show
    # find and return a specific message
  end

  # GET edit_message_url(:id => 1)
  def edit
    # return an HTML form for editing a specific message
  end

  # PUT message_url(:id => 1)
  def update
    # find and update a specific message
  end

  # DELETE message_url(:id => 1)
  def destroy
    # delete a specific message
  end
end

The #resources method sets HTTP method restrictions on the routes it generates. For example, making an HTTP POST on new_message_url will raise a RoutingError exception. The default route in config/routes.rb overrides this and allows invalid HTTP methods for resource routes.

Along with the routes themselves, #resources generates named routes for use in controllers and views. map.resources :messages produces the following named routes and helpers:

Named Route   Helpers
messages      messages_url, hash_for_messages_url, 
              messages_path, hash_for_messages_path
message       message_url(id), hash_for_message_url(id), 
              message_path(id), hash_for_message_path(id)
new_message   new_message_url, hash_for_new_message_url, 
              new_message_path, hash_for_new_message_path
edit_message  edit_message_url(id), hash_for_edit_message_url(id),
              edit_message_path(id), hash_for_edit_message_path(id)

You can use these helpers instead of #url_for or methods that take #url_for parameters:

redirect_to :controller => 'messages', :action => 'index'
# becomes
redirect_to messages_url

<%= link_to "edit this message", :controller => 'messages', :action => 'edit', :id => @message.id %>
# becomes
<%= link_to "edit this message", edit_message_url(@message) # calls @message.id automatically

Since web browsers don’t support the PUT and DELETE verbs, you will need to add a parameter ‘_method’ to your form tags. The form helpers make this a little easier. For an update form with a @message object:

<%= form_tag message_path(@message), :method => :put %>

or 

<% form_for :message, @message, message_path(@message), :html => {:method => :put} do |f| %>

The #resources method accepts various options, too, to customize the resulting routes:

  • :controller – specify the controller name for the routes.

  • :singular – specify the singular name used in the member routes.

  • :path_prefix – set a prefix to the routes with required route variables. Weblog comments usually belong to a post, so you might use resources like:

    map.resources :articles
map.resources :comments, :path_prefix => '/articles/:article_id'

    You can nest resources calls to set this automatically:

    map.resources :articles do |article|
  article.resources :comments
end

    The comment resources work the same, but must now include a value for :article_id.

    comments_url(@article)
comment_url(@article, @comment)

comments_url(:article_id => @article)
comment_url(:article_id => @article, :id => @comment)

  • :name_prefix – define a prefix for all generated routes, usually ending in an underscore. Use this if you have named routes that may clash.

    map.resources :tags, :path_prefix => '/books/:book_id', :name_prefix => 'book_'
map.resources :tags, :path_prefix => '/toys/:toy_id',   :name_prefix => 'toy_'

  • :collection – add named routes for other actions that operate on the collection. Takes a hash of #{action} => #{method}, where method is :get/:post/:put/:delete or :any if the method does not matter. These routes map to a URL like /messages;rss, with a route of rss_messages_url.

  • :member – same as :collection, but for actions that operate on a specific member.

  • :new – same as :collection, but for actions that operate on the new resource action.

If map.resources is called with multiple resources, they all get the same options applied.

Examples:

map.resources :messages, :path_prefix => "/thread/:thread_id"
# --> GET /thread/7/messages/1

map.resources :messages, :collection => { :rss => :get }
# --> GET /messages;rss (maps to the #rss action)
#     also adds a named route called "rss_messages"

map.resources :messages, :member => { :mark => :post }
# --> POST /messages/1;mark (maps to the #mark action)
#     also adds a named route called "mark_message"

map.resources :messages, :new => { :preview => :post }
# --> POST /messages/new;preview (maps to the #preview action)
#     also adds a named route called "preview_new_message"

map.resources :messages, :new => { :new => :any, :preview => :post }
# --> POST /messages/new;preview (maps to the #preview action)
#     also adds a named route called "preview_new_message"
# --> /messages/new can be invoked via any request method

map.resources :messages, :controller => "categories",
      :path_prefix => "/category/:category_id",
      :name_prefix => "category_"
# --> GET /categories/7/messages/1
#     has named route "category_message"



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# File 'lib/action_controller/resources.rb', line 215

def resources(*entities, &block)
  options = entities.last.is_a?(Hash) ? entities.pop : { }
  entities.each { |entity| map_resource entity, options.dup, &block }
end