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Class: ActionController::Metal

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
API, Base, Rails::ApplicationController, Rails::InfoController, Rails::MailersController, Rails::WelcomeController, ActionView::TestCase::TestController
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ::AbstractController::Base, ::ActiveSupport::DescendantsTracker
Instance Chain:
self, ::AbstractController::Base, ::ActiveSupport::Configurable
Inherits: AbstractController::Base
Defined in: actionpack/lib/action_controller/metal.rb,
actionpack/lib/action_controller/test_case.rb

Overview

Metal is the simplest possible controller, providing a valid ::Rack interface without the additional niceties provided by Base.

A sample metal controller might look like this:

class HelloController < ActionController::Metal
  def index
    self.response_body = "Hello World!"
  end
end

And then to route requests to your metal controller, you would add something like this to config/routes.rb:

get 'hello', to: HelloController.action(:index)

The .action method returns a valid ::Rack application for the Rails router to dispatch to.

Rendering Helpers

Metal by default provides no utilities for rendering views, partials, or other responses aside from explicitly calling of #response_body=, #content_type=, and #status=. To add the render helpers you’re used to having in a normal controller, you can do the following:

class HelloController < ActionController::Metal
  include AbstractController::Rendering
  include ActionView::Layouts
  append_view_path "#{Rails.root}/app/views"

  def index
    render "hello/index"
  end
end

Redirection Helpers

To add redirection helpers to your metal controller, do the following:

class HelloController < ActionController::Metal
  include ActionController::Redirecting
  include Rails.application.routes.url_helpers

  def index
    redirect_to root_url
  end
end

Other Helpers

You can refer to the modules included in Base to see other features you can bring into your metal controller.

Class Attribute Summary

::AbstractController::Base - Inherited

.abstract?

Alias for AbstractController::Base.abstract.
.supports_path?

Returns true if the given controller is capable of rendering a path.

Class Method Summary

::AbstractController::Base - Inherited

.abstract,
.abstract!

Define a controller as abstract.
.action_methods

A list of method names that should be considered actions.
.clear_action_methods!

action_methods are cached and there is sometimes a need to refresh them.
.controller_path

Returns the full controller name, underscored, without the ending Controller.
.internal_methods

A list of all internal methods for a controller.
.method_added

Refresh the cached action_methods when a new action_method is added.

::ActiveSupport::DescendantsTracker - Extended

descendants, direct_descendants, inherited,
subclasses

Alias for ActiveSupport::DescendantsTracker#direct_descendants.

Instance Attribute Summary

::AbstractController::Base - Inherited

#action_name

Returns the name of the action this controller is processing.
#formats

Returns the formats that can be processed by the controller.
#performed?

Tests if a response body is set.
#response_body

Returns the body of the HTTP response sent by the controller.

Instance Method Summary

::AbstractController::Base - Inherited

#action_methods

Delegates to the class’ .action_methods
#available_action?

Returns true if a method for the action is available and can be dispatched, false otherwise.
#controller_path

Delegates to the class’ .controller_path
#process

Calls the action going through the entire action dispatch stack.

::ActiveSupport::Configurable - Included

#config

Reads and writes attributes from a configuration OrderedOptions.

Constructor Details

.new ⇒ Metal

[ GitHub ] 

  


# File 'actionpack/lib/action_controller/metal.rb', line 152



def initialize
  @_request = nil
  @_response = nil
  @_routes = nil
  super
end


  







Class Attribute Details



  

    .middleware_stack   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 212



class_attribute :middleware_stack, default: ActionController::MiddlewareStack.new


  








  

    .middleware_stack?  ⇒ Boolean  (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 212



class_attribute :middleware_stack, default: ActionController::MiddlewareStack.new


  







Class Method Details



  

    .action(name)  
  



  

    

Returns a ::Rack endpoint for the given action name.


  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 234



def self.action(name)
  app = lambda { |env|
    req = ActionDispatch::Request.new(env)
    res = make_response! req
    new.dispatch(name, req, res)
  }

  if middleware_stack.any?
    middleware_stack.build(name, app)
  else
    app
  end
end


  








  

    .controller_name  
  



  

    

Returns the last part of the controller’s name, underscored, without the ending Controller. For instance, PostsController returns posts. Namespaces are left out, so Admin::PostsController returns posts as well.



Returns


  • 

    string
    



  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 128



def self.controller_name
  @controller_name ||= (name.demodulize.delete_suffix("Controller").underscore unless anonymous?)
end


  








  

    .dispatch(name, req, res)  
  



  

    

Direct dispatch to the controller. Instantiates the controller, then executes the action named name.


  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 250



def self.dispatch(name, req, res)
  if middleware_stack.any?
    middleware_stack.build(name) { |env| new.dispatch(name, req, res) }.call req.env
  else
    new.dispatch(name, req, res)
  end
end


  








  

    .make_response!(request)  
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 132



def self.make_response!(request)
  ActionDispatch::Response.new.tap do |res|
    res.request = request
  end
end


  








  

    .middleware  
  



  

    

Alias for .middleware_stack.


  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 229



def self.middleware
  middleware_stack
end


  








  

    .use(*args, &block)  
  



  

    

Pushes the given ::Rack middleware and its arguments to the bottom of the middleware stack.


  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 222



def use(*args, &block)
  middleware_stack.use(*args, &block)
end


  







Instance Attribute Details



  

    #content_type   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 149



delegate :headers, :status=, :location=, :content_type=,
         :status, :location, :content_type, :media_type, to: "@_response"


  








  

    #headers   (readonly)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 149



delegate :headers, :status=, :location=, :content_type=,
         :status, :location, :content_type, :media_type, to: "@_response"


  








  

    #location   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 149



delegate :headers, :status=, :location=, :content_type=,
         :status, :location, :content_type, :media_type, to: "@_response"


  








  

    #media_type   (readonly)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 149



delegate :headers, :status=, :location=, :content_type=,
         :status, :location, :content_type, :media_type, to: "@_response"


  








  

    #middleware_stack   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 212



class_attribute :middleware_stack, default: ActionController::MiddlewareStack.new


  








  

    #middleware_stack?  ⇒ Boolean  (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 212



class_attribute :middleware_stack, default: ActionController::MiddlewareStack.new


  








  

    #params   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 159



def params
  @_params ||= request.parameters
end


  








  

    #params=(val)   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 163



def params=(val)
  @_params = val
end


  








  

    #performed?  ⇒ Boolean  (readonly)
  



  

    

Tests if render or redirect has already happened.


  





  


  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 183



def performed?
  response_body || response.committed?
end


  








  

    #request   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 147



attr_internal :response, :request


  








  

    #response   (rw)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 147



attr_internal :response, :request


  








  

    #response_body=(body)   (writeonly)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 174



def response_body=(body)
  body = [body] unless body.nil? || body.respond_to?(:each)
  response.reset_body!
  return unless body
  response.body = body
  super
end


  








  

    #session   (readonly)
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 148



delegate :session, to: "@_request"


  








  

    #status   (rw)
    Also known as: #response_code
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 149



delegate :headers, :status=, :location=, :content_type=,
         :status, :location, :content_type, :media_type, to: "@_response"


  







Instance Method Details



  

    #controller_name  
  



  

    

Delegates to the class’ controller_name.


  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 143



def controller_name
  self.class.controller_name
end


  








  

    #reset_session  
  

  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 208



def reset_session
  @_request.reset_session
end


  








  

    #url_for(string)  
  



  

    

Basic url_for that can be overridden for more robust functionality.


  



  [ GitHub ]


  

  


# File 'actionpack/lib/action_controller/metal.rb', line 170



def url_for(string)
  string
end