ActionController::Metal

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

match 'hello', :to => HelloController.action(:index)

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

Rendering Helpers

ActionController::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 ActionController::Rendering
  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 ActionController::Base to see other features you can bring into your metal controller.

Methods

A

action

C

E

env

L

location,
location=

M

middleware

N

new

P

R

response_body=

S

status,
status=

U

url_for,
use

Class Public methods

action(name, klass = ActionDispatch::Request)

Return a rack endpoint for the given action. Memoize the endpoint, so multiple calls into MyController.action will return the same object for the same action.

Parameters

action - An action name

Returns

proc - A rack application

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 244
def self.action(name, klass = ActionDispatch::Request)
  middleware_stack.build(name.to_s) do |env|
    new.dispatch(name, klass.new(env))
  end
end

call(env)

Makes the controller a rack endpoint that points to the action in the given env’s action_dispatch.request.path_parameters key.

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 231
def self.call(env)
  action(env['action_dispatch.request.path_parameters'][:action]).call(env)
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

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 116
def self.controller_name
  @controller_name ||= self.name.demodulize.sub(%rController$/, '').underscore
end

middleware()

Alias for middleware_stack

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 225
def self.middleware
  middleware_stack
end

new()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 134
def initialize
  @_headers = {"Content-Type" => "text/html"}
  @_status = 200
  @_request = nil
  @_response = nil
  @_routes = nil
  super
end

use(*args, &block)

Adds given middleware class and its args to bottom of middleware_stack

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 220
def self.use(*args, &block)
  middleware_stack.use(*args, &block)
end

Instance Public methods

content_type()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 159
def content_type
  headers["Content-Type"]
end

content_type=(type)

Basic implementations for #content_type=, location=, and headers are provided to reduce the dependency on the RackDelegation module in Renderer and Redirector.

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 155
def content_type=(type)
  headers["Content-Type"] = type.to_s
end

controller_name()

Delegates to the class’ controller_name

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 121
def controller_name
  self.class.controller_name
end

env()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 106
def env
  @_env ||= {}
end

location()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 163
def location
  headers["Location"]
end

location=(url)

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 167
def location=(url)
  headers["Location"] = url
end

params()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 143
def params
  @_params ||= request.parameters
end

params=(val)

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 147
def params=(val)
  @_params = val
end

performed?()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 195
def performed?
  response_body
end

response_body=(val)

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 184
def response_body=(val)
  body = if val.is_a?(String)
    [val]
  elsif val.nil? || val.respond_to?(:each)
    val
  else
    [val]
  end
  super body
end

status()

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 176
def status
  @_status
end

status=(status)

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 180
def status=(status)
  @_status = Rack::Utils.status_code(status)
end

url_for(string)

basic #url_for that can be overridden for more robust functionality

Source: show | on GitHub

# File actionpack/lib/action_controller/metal.rb, line 172
def url_for(string)
  string
end