1 files changed, 136 insertions, 0 deletions
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
new file mode 100644
index 0000000000..02c4e563f5
--- /dev/null
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -0,0 +1,136 @@
+require 'set'
+
+module ActionController
+  # See <tt>Renderers.add</tt>
+  def self.add_renderer(key, &block)
+    Renderers.add(key, &block)
+  end
+
+  # See <tt>Renderers.remove</tt>
+  def self.remove_renderer(key)
+    Renderers.remove(key)
+  end
+
+  class MissingRenderer < LoadError
+    def initialize(format)
+      super "No renderer defined for format: #{format}"
+    end
+  end
+
+  module Renderers
+    extend ActiveSupport::Concern
+
+    included do
+      class_attribute :_renderers
+      self._renderers = Set.new.freeze
+    end
+
+    module ClassMethods
+      def use_renderers(*args)
+        renderers = _renderers + args
+        self._renderers = renderers.freeze
+      end
+      alias use_renderer use_renderers
+    end
+
+    def render_to_body(options)
+      _handle_render_options(options) || super
+    end
+
+    def _handle_render_options(options)
+      _renderers.each do |name|
+        if options.key?(name)
+          _process_options(options)
+          return send("_render_option_#{name}", options.delete(name), options)
+        end
+      end
+      nil
+    end
+
+    # A Set containing renderer names that correspond to available renderer procs.
+    # Default values are <tt>:json</tt>, <tt>:js</tt>, <tt>:xml</tt>.
+    RENDERERS = Set.new
+
+    # Adds a new renderer to call within controller actions.
+    # A renderer is invoked by passing its name as an option to
+    # <tt>AbstractController::Rendering#render</tt>. To create a renderer
+    # pass it a name and a block. The block takes two arguments, the first
+    # is the value paired with its key and the second is the remaining
+    # hash of options passed to +render+.
+    #
+    # Create a csv renderer:
+    #
+    #   ActionController::Renderers.add :csv do |obj, options|
+    #     filename = options[:filename] || 'data'
+    #     str = obj.respond_to?(:to_csv) ? obj.to_csv : obj.to_s
+    #     send_data str, type: Mime::CSV,
+    #       disposition: "attachment; filename=#{filename}.csv"
+    #   end
+    #
+    # Note that we used Mime::CSV for the csv mime type as it comes with Rails.
+    # For a custom renderer, you'll need to register a mime type with
+    # <tt>Mime::Type.register</tt>.
+    #
+    # To use the csv renderer in a controller action:
+    #
+    #   def show
+    #     @csvable = Csvable.find(params[:id])
+    #     respond_to do |format|
+    #       format.html
+    #       format.csv { render csv: @csvable, filename: @csvable.name }
+    #     end
+    #   end
+    # To use renderers and their mime types in more concise ways, see
+    # <tt>ActionController::MimeResponds::ClassMethods.respond_to</tt> and
+    # <tt>ActionController::MimeResponds#respond_with</tt>
+    def self.add(key, &block)
+      define_method("_render_option_#{key}", &block)
+      RENDERERS << key.to_sym
+    end
+
+    # This method is the opposite of add method.
+    #
+    # Usage:
+    #
+    #   ActionController::Renderers.remove(:csv)
+    def self.remove(key)
+      RENDERERS.delete(key.to_sym)
+      method = "_render_option_#{key}"
+      remove_method(method) if method_defined?(method)
+    end
+
+    module All
+      extend ActiveSupport::Concern
+      include Renderers
+
+      included do
+        self._renderers = RENDERERS
+      end
+    end
+
+    add :json do |json, options|
+      json = json.to_json(options) unless json.kind_of?(String)
+
+      if options[:callback].present?
+        if self.content_type.nil? || self.content_type == Mime::JSON
+          self.content_type = Mime::JS
+        end
+
+        "/**/#{options[:callback]}(#{json})"
+      else
+        self.content_type ||= Mime::JSON
+        json
+      end
+    end
+
+    add :js do |js, options|
+      self.content_type ||= Mime::JS
+      js.respond_to?(:to_js) ? js.to_js(options) : js
+    end
+
+    add :xml do |xml, options|
+      self.content_type ||= Mime::XML
+      xml.respond_to?(:to_xml) ? xml.to_xml(options) : xml
+    end
+  end
+end