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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
F
N
R
W
Constants
DEFAULTS = { http_host: "example.org", https: false, method: "get", script_name: "", input: "" }.freeze
 
RACK_KEY_TRANSLATION = { http_host: "HTTP_HOST", https: "HTTPS", method: "REQUEST_METHOD", script_name: "SCRIPT_NAME", input: "rack.input" }
 
IDENTITY = ->(_) { _ }
 
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.

# File actionpack/lib/action_controller/renderer.rb, line 49
def self.for(controller, env = {}, defaults = DEFAULTS.dup)
  new(controller, env, defaults)
end
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.

# File actionpack/lib/action_controller/renderer.rb, line 66
def initialize(controller, env, defaults)
  @controller = controller
  @defaults = defaults
  @env = normalize_keys defaults.merge(env)
end
Instance Public methods
new(env = {})

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

# File actionpack/lib/action_controller/renderer.rb, line 54
def new(env = {})
  self.class.new controller, env, defaults
end
render(*args)

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

# File actionpack/lib/action_controller/renderer.rb, line 73
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
with_defaults(defaults)

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

# File actionpack/lib/action_controller/renderer.rb, line 59
def with_defaults(defaults)
  self.class.new controller, @env, self.defaults.merge(defaults)
end