module ActionController::Rendering

Constants

RENDER_FORMATS_IN_PRIORITY

Public Instance Methods

render(*args) click to toggle source

Renders a template and assigns the result to self.response_body.

If no rendering mode option is specified, the template will be derived from the first argument.

render "posts/show"
# => renders app/views/posts/show.html.erb

# In a PostsController action...
render :show
# => renders app/views/posts/show.html.erb

If the first argument responds to render_in, the template will be rendered by calling render_in with the current view context.

class Greeting
  def render_in(view_context)
    view_context.render html: "<h1>Hello, World</h1>"
  end

  def format
    :html
  end
end

render(Greeting.new)
# => "<h1>Hello, World</h1>"

render(renderable: Greeting.new)
# => "<h1>Hello, World</h1>"

Rendering Mode

:partial

See ActionView::PartialRenderer for details.

    render partial: "posts/form", locals: { post: Post.new }
    # => renders app/views/posts/_form.html.erb
:file

Renders the contents of a file. This option should not be used with unsanitized user input.

    render file: "/path/to/some/file"
    # => renders /path/to/some/file
:inline

Renders an ERB template string.

    @name = "World"
    render inline: "<h1>Hello, <%= @name %>!</h1>"
    # => renders "<h1>Hello, World!</h1>"
:body

Renders the provided text, and sets the content type as text/plain.

    render body: "Hello, World!"
    # => renders "Hello, World!"
:plain

Renders the provided text, and sets the content type as text/plain.

    render plain: "Hello, World!"
    # => renders "Hello, World!"
:html

Renders the provided HTML string, and sets the content type as text/html. If the string is not html_safe?, performs HTML escaping on the string before rendering.

    render html: "<h1>Hello, World!</h1>".html_safe
    # => renders "<h1>Hello, World!</h1>"

    render html: "<h1>Hello, World!</h1>"
    # => renders "&lt;h1&gt;Hello, World!&lt;/h1&gt;"
:json

Renders the provided object as JSON, and sets the content type as application/json. If the object is not a string, it will be converted to JSON by calling to_json.

    render json: { hello: "world" }
    # => renders "{\"hello\":\"world\"}"
:renderable

Renders the provided object by calling render_in with the current view context. The response format is determined by calling format on the renderable if it responds to format, falling back to text/html by default.

    render renderable: Greeting.new
    # => renders "<h1>Hello, World</h1>"

By default, when a rendering mode is specified, no layout template is rendered.

Options

:assigns

Hash of instance variable assignments for the template.

    render inline: "<h1>Hello, <%= @name %>!</h1>", assigns: { name: "World" }
    # => renders "<h1>Hello, World!</h1>"
:locals

Hash of local variable assignments for the template.

    render inline: "<h1>Hello, <%= name %>!</h1>", locals: { name: "World" }
    # => renders "<h1>Hello, World!</h1>"
:layout

The layout template to render. Can also be false or true to disable or (re)enable the default layout template.

    render "posts/show", layout: "holiday"
    # => renders app/views/posts/show.html.erb with the app/views/layouts/holiday.html.erb layout

    render "posts/show", layout: false
    # => renders app/views/posts/show.html.erb with no layout

    render inline: "<h1>Hello, World!</h1>", layout: true
    # => renders "<h1>Hello, World!</h1>" with the default layout
:status

The HTTP status code to send with the response. Can be specified as a number or as the status name in Symbol form. Defaults to 200.

    render "posts/new", status: 422
    # => renders app/views/posts/new.html.erb with HTTP status code 422

    render "posts/new", status: :unprocessable_entity
    # => renders app/views/posts/new.html.erb with HTTP status code 422
Calls superclass method
# File lib/action_controller/metal/rendering.rb, line 165
def render(*args)
  raise ::AbstractController::DoubleRenderError if response_body
  super
end
render_to_string(*) click to toggle source

Similar to render, but only returns the rendered template as a string, instead of setting self.response_body.

Calls superclass method
# File lib/action_controller/metal/rendering.rb, line 174
def render_to_string(*)
  result = super
  if result.respond_to?(:each)
    string = +""
    result.each { |r| string << r }
    string
  else
    result
  end
end

Private Instance Methods

_normalize_options(options) click to toggle source

Normalize both text and status options.

Calls superclass method
# File lib/action_controller/metal/rendering.rb, line 227
def _normalize_options(options)
  _normalize_text(options)

  if options[:html]
    options[:html] = ERB::Util.html_escape(options[:html])
  end

  if options[:status]
    options[:status] = Rack::Utils.status_code(options[:status])
  end

  super
end
_normalize_text(options) click to toggle source
# File lib/action_controller/metal/rendering.rb, line 241
def _normalize_text(options)
  RENDER_FORMATS_IN_PRIORITY.each do |format|
    if options.key?(format) && options[format].respond_to?(:to_text)
      options[format] = options[format].to_text
    end
  end
end
_process_options(options) click to toggle source

Process controller specific options, as status, content-type and location.

Calls superclass method
# File lib/action_controller/metal/rendering.rb, line 250
def _process_options(options)
  status, content_type, location = options.values_at(:status, :content_type, :location)

  self.status = status if status
  self.content_type = content_type if content_type
  headers["Location"] = url_for(location) if location

  super
end
_process_variant(options) click to toggle source
# File lib/action_controller/metal/rendering.rb, line 196
def _process_variant(options)
  if defined?(request) && !request.nil? && request.variant.present?
    options[:variant] = request.variant
  end
end
_render_in_priorities(options) click to toggle source
# File lib/action_controller/metal/rendering.rb, line 202
def _render_in_priorities(options)
  RENDER_FORMATS_IN_PRIORITY.each do |format|
    return options[format] if options.key?(format)
  end

  nil
end
_set_html_content_type() click to toggle source
# File lib/action_controller/metal/rendering.rb, line 210
def _set_html_content_type
  self.content_type = Mime[:html].to_s
end
_set_rendered_content_type(format) click to toggle source
# File lib/action_controller/metal/rendering.rb, line 214
def _set_rendered_content_type(format)
  if format && !response.media_type
    self.content_type = format.to_s
  end
end
_set_vary_header() click to toggle source
# File lib/action_controller/metal/rendering.rb, line 220
def _set_vary_header
  if response.headers["Vary"].blank? && request.should_apply_vary_header?
    response.headers["Vary"] = "Accept"
  end
end