require 'abstract_controller/collector' require 'active_support/core_ext/class/attribute' require 'active_support/core_ext/object/inclusion' module ActionController #:nodoc: module MimeResponds extend ActiveSupport::Concern include ActionController::ImplicitRender included do class_attribute :responder, :mimes_for_respond_to self.responder = ActionController::Responder clear_respond_to end module ClassMethods # Defines mime types that are rendered by default when invoking # respond_with. # # Examples: # # respond_to :html, :xml, :json # # Specifies that all actions in the controller respond to requests # for :html, :xml and :json. # # To specify on per-action basis, use :only and # :except with an array of actions or a single action: # # respond_to :html # respond_to :xml, :json, :except => [ :edit ] # # This specifies that all actions respond to :html # and all actions except :edit respond to :xml and # :json. # # respond_to :json, :only => :create # # This specifies that the :create action and no other responds # to :json. def respond_to(*mimes) options = mimes.extract_options! only_actions = Array(options.delete(:only)).map(&:to_s) except_actions = Array(options.delete(:except)).map(&:to_s) new = mimes_for_respond_to.dup mimes.each do |mime| mime = mime.to_sym new[mime] = {} new[mime][:only] = only_actions unless only_actions.empty? new[mime][:except] = except_actions unless except_actions.empty? end self.mimes_for_respond_to = new.freeze end # Clear all mime types in respond_to. # def clear_respond_to self.mimes_for_respond_to = ActiveSupport::OrderedHash.new.freeze end end # Without web-service support, an action which collects the data for displaying a list of people # might look something like this: # # def index # @people = Person.all # end # # Here's the same action, with web-service support baked in: # # def index # @people = Person.all # # respond_to do |format| # format.html # format.xml { render :xml => @people.to_xml } # end # end # # What that says is, "if the client wants HTML in response to this action, just respond as we # would have before, but if the client wants XML, return them the list of people in XML format." # (Rails determines the desired response format from the HTTP Accept header submitted by the client.) # # Supposing you have an action that adds a new person, optionally creating their company # (by name) if it does not already exist, without web-services, it might look like this: # # def create # @company = Company.find_or_create_by_name(params[:company][:name]) # @person = @company.people.create(params[:person]) # # redirect_to(person_list_url) # end # # Here's the same action, with web-service support baked in: # # def create # company = params[:person].delete(:company) # @company = Company.find_or_create_by_name(company[:name]) # @person = @company.people.create(params[:person]) # # respond_to do |format| # format.html { redirect_to(person_list_url) } # format.js # format.xml { render :xml => @person.to_xml(:include => @company) } # end # end # # If the client wants HTML, we just redirect them back to the person list. If they want JavaScript, # then it is an Ajax request and we render the JavaScript template associated with this action. # Lastly, if the client wants XML, we render the created person as XML, but with a twist: we also # include the person's company in the rendered XML, so you get something like this: # # # ... # ... # # ... # ... # ... # # # # Note, however, the extra bit at the top of that action: # # company = params[:person].delete(:company) # @company = Company.find_or_create_by_name(company[:name]) # # This is because the incoming XML document (if a web-service request is in process) can only contain a # single root-node. So, we have to rearrange things so that the request looks like this (url-encoded): # # person[name]=...&person[company][name]=...&... # # And, like this (xml-encoded): # # # ... # # ... # # # # In other words, we make the request so that it operates on a single entity's person. Then, in the action, # we extract the company data from the request, find or create the company, and then create the new person # with the remaining data. # # Note that you can define your own XML parameter parser which would allow you to describe multiple entities # in a single request (i.e., by wrapping them all in a single root node), but if you just go with the flow # and accept Rails' defaults, life will be much easier. # # If you need to use a MIME type which isn't supported by default, you can register your own handlers in # config/initializers/mime_types.rb as follows. # # Mime::Type.register "image/jpg", :jpg # # Respond to also allows you to specify a common block for different formats by using any: # # def index # @people = Person.all # # respond_to do |format| # format.html # format.any(:xml, :json) { render request.format.to_sym => @people } # end # end # # In the example above, if the format is xml, it will render: # # render :xml => @people # # Or if the format is json: # # render :json => @people # # Since this is a common pattern, you can use the class method respond_to # with the respond_with method to have the same results: # # class PeopleController < ApplicationController # respond_to :html, :xml, :json # # def index # @people = Person.all # respond_with(@person) # end # end # # Be sure to check respond_with and respond_to documentation for more examples. # def respond_to(*mimes, &block) raise ArgumentError, "respond_to takes either types or a block, never both" if mimes.any? && block_given? if response = retrieve_response_from_mimes(mimes, &block) response.call(nil) end end # respond_with wraps a resource around a responder for default representation. # First it invokes respond_to, if a response cannot be found (ie. no block # for the request was given and template was not available), it instantiates # an ActionController::Responder with the controller and resource. # # ==== Example # # def index # @users = User.all # respond_with(@users) # end # # It also accepts a block to be given. It's used to overwrite a default # response: # # def create # @user = User.new(params[:user]) # flash[:notice] = "User was successfully created." if @user.save # # respond_with(@user) do |format| # format.html { render } # end # end # # All options given to respond_with are sent to the underlying responder, # except for the option :responder itself. Since the responder interface # is quite simple (it just needs to respond to call), you can even give # a proc to it. # # In order to use respond_with, first you need to declare the formats your # controller responds to in the class level with a call to respond_to. # def respond_with(*resources, &block) raise "In order to use respond_with, first you need to declare the formats your " << "controller responds to in the class level" if self.class.mimes_for_respond_to.empty? if response = retrieve_response_from_mimes(&block) options = resources.size == 1 ? {} : resources.extract_options! options.merge!(:default_response => response) (options.delete(:responder) || self.class.responder).call(self, resources, options) end end protected # Collect mimes declared in the class method respond_to valid for the # current action. # def collect_mimes_from_class_level #:nodoc: action = action_name.to_s self.class.mimes_for_respond_to.keys.select do |mime| config = self.class.mimes_for_respond_to[mime] if config[:except] !action.in?(config[:except]) elsif config[:only] action.in?(config[:only]) else true end end end # Collects mimes and return the response for the negotiated format. Returns # nil if :not_acceptable was sent to the client. # def retrieve_response_from_mimes(mimes=nil, &block) #:nodoc: mimes ||= collect_mimes_from_class_level collector = Collector.new(mimes) { |options| default_render(options || {}) } block.call(collector) if block_given? if format = request.negotiate_mime(collector.order) self.content_type ||= format.to_s lookup_context.freeze_formats([format.to_sym]) collector.response_for(format) else head :not_acceptable nil end end class Collector #:nodoc: include AbstractController::Collector attr_accessor :order def initialize(mimes, &block) @order, @responses, @default_response = [], {}, block mimes.each { |mime| send(mime) } end def any(*args, &block) if args.any? args.each { |type| send(type, &block) } else custom(Mime::ALL, &block) end end alias :all :any def custom(mime_type, &block) mime_type = Mime::Type.lookup(mime_type.to_s) unless mime_type.is_a?(Mime::Type) @order << mime_type @responses[mime_type] ||= block end def response_for(mime) @responses[mime] || @responses[Mime::ALL] || @default_response end end end end