module ActionController #:nodoc: module MimeResponds #:nodoc: def self.included(base) base.send(:include, ActionController::MimeResponds::InstanceMethods) end module InstanceMethods # Without web-service support, an action which collects the data for displaying a list of people # might look something like this: # # def list # @people = Person.find(:all) # end # # Here's the same action, with web-service support baked in: # # def list # @people = Person.find(:all) # # respond_to do |wants| # wants.html # wants.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 add # @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 add # company = params[:person].delete(:company) # @company = Company.find_or_create_by_name(company[:name]) # @person = @company.people.create(params[:person]) # # respond_to do |wants| # wants.html { redirect_to(person_list_url) } # wants.js # wants.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 # (wants.js), then it is an RJS request and we render the RJS 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—a 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 note), but if you just go with the flow # and accept Rails' defaults, life will be much easier. def respond_to(*types, &block) raise ArgumentError, "respond_to takes either types or a block, never bot" unless types.any? ^ block block ||= lambda { |responder| types.each { |type| responder.send(type) } } responder = Responder.new(block.binding) block.call(responder) responder.respond end end class Responder #:nodoc: DEFAULT_BLOCKS = { :html => 'Proc.new { render }', :js => 'Proc.new { render :action => "#{action_name}.rjs" }', :xml => 'Proc.new { render :action => "#{action_name}.rxml" }' } def initialize(block_binding) @block_binding = block_binding @mime_type_priority = eval( "(params[:format] && Mime::EXTENSION_LOOKUP[params[:format]]) ? " + "[ Mime::EXTENSION_LOOKUP[params[:format]] ] : request.accepts", block_binding ) @order = [] @responses = {} end def custom(mime_type, &block) mime_type = mime_type.is_a?(Mime::Type) ? mime_type : Mime::Type.lookup(mime_type.to_s) @order << mime_type if block_given? @responses[mime_type] = block else @responses[mime_type] = eval(DEFAULT_BLOCKS[mime_type.to_sym], @block_binding) end end def any(*args, &block) args.each { |type| send(type, &block) } end def method_missing(symbol, &block) mime_constant = symbol.to_s.upcase if Mime::SET.include?(Mime.const_get(mime_constant)) custom(Mime.const_get(mime_constant), &block) else super end end def respond for priority in @mime_type_priority if priority == Mime::ALL @responses[@order.first].call return else if priority === @order @responses[priority].call return # mime type match found, be happy and return end end end if @order.include?(Mime::ALL) @responses[Mime::ALL].call else eval 'render(:nothing => true, :status => "406 Not Acceptable")', @block_binding end end end end end