ActionController::Renderer allows you to render arbitrary templates without requirement of being in controller actions.

You get a concrete renderer class by invoking ActionController::Base#renderer. For example:

ApplicationController.renderer

It allows you to call method render directly.

ApplicationController.renderer.render template: '...'

You can use this shortcut in a controller, instead of the previous example:

ApplicationController.render template: '...'

render allows you to use the same options that you can use when rendering in a controller. For example:

FooController.render :action, locals: { ... }, assigns: { ... }

The template will be rendered in a Rack environment which is accessible through ActionController::Renderer#env. You can set it up in two ways:

  • by changing renderer defaults, like

    ApplicationController.renderer.defaults # => hash with default Rack environment

  • by initializing an instance of renderer by passing it a custom environment.

    ApplicationController.renderer.new(method: 'post', https: true)

Methods

Constants

DEFAULTS = { http_host: "example.org", https: false, method: "get", script_name: "", input: "" }.freeze
IDENTITY = ->(_) { _ }
RACK_KEY_TRANSLATION = { http_host: "HTTP_HOST", https: "HTTPS", method: "REQUEST_METHOD", script_name: "SCRIPT_NAME", input: "rack.input" }
RACK_VALUE_TRANSLATION = { https: ->(v) { v ? "on" : "off" }, method: ->(v) { v.upcase }, }

Attributes

[R] controller
[R] defaults

Class Public methods

for(controller, env = {}, defaults = DEFAULTS.dup)

Create a new renderer instance for a specific controller class.

📝 Source code 
# File actionpack/lib/action_controller/renderer.rb, line 50
    def self.for(controller, env = {}, defaults = DEFAULTS.dup)
      new(controller, env, defaults)
    end
🔎 See on GitHub

new(controller, env, defaults)

Accepts a custom Rack environment to render templates in. It will be merged with the default Rack environment defined by ActionController::Renderer::DEFAULTS.

📝 Source code 
# File actionpack/lib/action_controller/renderer.rb, line 67
    def initialize(controller, env, defaults)
      @controller = controller
      @defaults = defaults
      @env = normalize_keys defaults.merge(env)
    end
🔎 See on GitHub

Instance Public methods

new(env = {})

Create a new renderer for the same controller but with a new env.

📝 Source code 
# File actionpack/lib/action_controller/renderer.rb, line 55
    def new(env = {})
      self.class.new controller, env, defaults
    end
🔎 See on GitHub

render(*args)

Render templates with any options from ActionController::Base#render_to_string.

📝 Source code 
# File actionpack/lib/action_controller/renderer.rb, line 74
    def render(*args)
      raise "missing controller" unless controller

      request = ActionDispatch::Request.new @env
      request.routes = controller._routes

      instance = controller.new
      instance.set_request! request
      instance.set_response! controller.make_response!(request)
      instance.render_to_string(*args)
    end
🔎 See on GitHub

with_defaults(defaults)

Create a new renderer for the same controller but with new defaults.

📝 Source code 
# File actionpack/lib/action_controller/renderer.rb, line 60
    def with_defaults(defaults)
      self.class.new controller, @env, self.defaults.merge(defaults)
    end
🔎 See on GitHub