Module: ActionController::Resources
- Included in:
- ActionController::Routing::RouteSet::Mapper
- Defined in:
- lib/action_controller/resources.rb
Overview
Overview
ActionController::Resources are a way of defining RESTful resources. A RESTful resource, in basic terms, is something that can be pointed at and it will respond with a representation of the data requested. In real terms this could mean a user with a browser requests an HTML page, or that a desktop application requests XML data.
RESTful design is based on the assumption that there are four generic verbs that a user of an application can request from a resource (the noun).
Resources can be requested using four basic HTTP verbs (GET, POST, PUT, DELETE), the method used denotes the type of action that should take place.
The Different Methods and their Usage
GET
Requests for a resource, no saving or editing of a resource should occur in a GET request POST
Creation of resources PUT
Editing of attributes on a resource DELETE
Deletion of a resource
Examples
# A GET request on the Posts resource is asking for all Posts
GET /posts
# A GET request on a single Post resource is asking for that particular Post
GET /posts/1
# A POST request on the Posts resource is asking for a Post to be created with the supplied details
POST /posts # with => { :post => { :title => "My Whizzy New Post", :body => "I've got a brand new combine harvester" } }
# A PUT request on a single Post resource is asking for a Post to be updated
PUT /posts # with => { :id => 1, :post => { :title => "Changed Whizzy Title" } }
# A DELETE request on a single Post resource is asking for it to be deleted
DELETE /posts # with => { :id => 1 }
By using the REST convention, users of our application can assume certain things about how the data is requested and how it is returned. Rails simplifies the routing part of RESTful design by supplying you with methods to create them in your routes.rb file.
Read more about REST at en.wikipedia.org/wiki/Representational_State_Transfer
Defined Under Namespace
Classes: Resource, SingletonResource
Instance Method Summary collapse
-
#resource(*entities, &block) ⇒ Object
Creates named routes for implementing verb-oriented controllers for a singleton resource.
-
#resources(*entities, &block) ⇒ Object
Creates named routes for implementing verb-oriented controllers for a collection resource.
Instance Method Details
#resource(*entities, &block) ⇒ Object
Creates named routes for implementing verb-oriented controllers for a singleton resource. A singleton resource is global to its current context. For unnested singleton resources, the resource is global to the current user visiting the application, such as a user’s /account profile. For nested singleton resources, the resource is global to its parent resource, such as a projects
resource that has_one :project_manager
. The project_manager
should be mapped as a singleton resource under projects
:
map.resources :projects do |project|
project.resource :project_manager
end
See map.resources for general conventions. These are the main differences:
-
A singular name is given to map.resource. The default controller name is still taken from the plural name.
-
To specify a custom plural name, use the
:plural
option. There is no:singular
option. -
No default index route is created for the singleton resource controller.
-
When nesting singleton resources, only the singular name is used as the path prefix (example: ‘account/messages/1’)
For example:
map.resource :account
maps these actions in the Accounts controller:
class AccountsController < ActionController::Base
# GET new_account_url
def new
# return an HTML form for describing the new account
end
# POST account_url
def create
# create an account
end
# GET account_url
def show
# find and return the account
end
# GET edit_account_url
def edit
# return an HTML form for editing the account
end
# PUT account_url
def update
# find and update the account
end
# DELETE account_url
def destroy
# delete the account
end
end
Along with the routes themselves, resource
generates named routes for use in controllers and views. map.resource :account
produces these named routes and helpers:
Named Route Helpers
============ =============================================
account account_url, hash_for_account_url,
account_path, hash_for_account_path
new_account new_account_url, hash_for_new_account_url,
new_account_path, hash_for_new_account_path
edit_account edit_account_url, hash_for_edit_account_url,
edit_account_path, hash_for_edit_account_path
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# File 'lib/action_controller/resources.rb', line 423 def resource(*entities, &block) = entities. entities.each { |entity| map_singleton_resource(entity, .dup, &block) } end |
#resources(*entities, &block) ⇒ Object
Creates named routes for implementing verb-oriented controllers for a collection resource.
For example:
map.resources :messages
will map the following actions in the corresponding controller:
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
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. For example:
redirect_to :controller => 'messages', :action => 'index'
# and
<%= link_to "edit this message", :controller => 'messages', :action => 'edit', :id => @message.id %>
now become:
redirect_to messages_url
# and
<%= 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, :url => message_path(@message), :html => {:method => :put} do |f| %>
or
<% form_for @message do |f| %>
which takes into account whether @message
is a new record or not and generates the path and method accordingly.
The resources
method accepts the following options to customize the resulting routes:
-
: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 ofrss_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. -
:controller
- Specify the controller name for the routes. -
:singular
- Specify the singular name used in the member routes. -
:requirements
- Set custom routing parameter requirements. -
:conditions
- Specify custom routing recognition conditions. Resources sets the:method
value for the method-specific routes. -
:as
- Specify a different resource name to use in the URL path. For example:# products_path == '/productos' map.resources :products, :as => 'productos' do |product| # product_reviews_path(product) == '/productos/1234/comentarios' product.resources :product_reviews, :as => 'comentarios' end
-
:has_one
- Specify nested resources, this is a shorthand for mapping singleton resources beneath the current. -
:has_many
- Same has:has_one
, but for plural resources.You may directly specify the routing association with
has_one
andhas_many
like:map.resources :notes, :has_one => :author, :has_many => [:comments, :attachments]
This is the same as:
map.resources :notes do |notes| notes.resource :author notes.resources :comments notes.resources :attachments end
-
:path_names
- Specify different names for the ‘new’ and ‘edit’ actions. For example:# new_products_path == '/productos/nuevo' map.resources :products, :as => 'productos', :path_names => { :new => 'nuevo', :edit => 'editar' }
You can also set default action names from an environment, like this:
config.action_controller.resources_path_names = { :new => 'nuevo', :edit => 'editar' }
-
: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
.article_comments_url(@article) article_comment_url(@article, @comment) article_comments_url(:article_id => @article) 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_'
You may also use :name_prefix
to override the generic named routes in a nested resource:
map.resources :articles do |article|
article.resources :comments, :name_prefix => nil
end
This will yield named resources like so:
comments_url(@article)
comment_url(@article, @comment)
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"
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.
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# File 'lib/action_controller/resources.rb', line 349 def resources(*entities, &block) = entities. entities.each { |entity| map_resource(entity, .dup, &block) } end |