Fast Rails APIs with representer - Railsberry 2012

Slides for presentation delivered at Railsberry 2012 in Krakow, where I spoke how to speeding up Rails with faster JSON generation and tweaking Rails.

Transcript

1. Fast Rails APIs Railsberry Kraków April 19th, 2012 Monday, April 23, 12
2. ms Monday, April 23, 12
3. Monday, April 23, 12
4. Monday, April 23, 12
5. Monday, April 23, 12
6. Interpreted Dynamic typing Object-Oriented Monday, April 23, 12
7. Speed is a feature Monday, April 23, 12
8. Request Router Controller Response Monday, April 23, 12
9. Request Router Controller Response Monday, April 23, 12
10. ActionController::Metal Monday, April 23, 12
11. class NormalController < ActionController::Base def index @messages = Message.paginate(:page => params[:page]) respond_to do |format| format.json { render :json => @messages } end end end Monday, April 23, 12
12. class MetalController < ActionController::Metal def index @messages = Message.paginate(:page => params[:page]) self.response_body = @messages.to_json self.status = 200 self.content_type = 'application/json' end end Monday, April 23, 12
13. 0 175 350 525 700 Requests/second Normal Light Monday, April 23, 12
14. M V C Monday, April 23, 12
15. render :json => @posts Monday, April 23, 12
16. @posts.to_json Monday, April 23, 12
17. M C Monday, April 23, 12
18. Representer pattern Monday, April 23, 12
19. apotonick/roar josevalim/active_model_serializers Monday, April 23, 12
20. representer Monday, April 23, 12
21. Representer == Object Oriented View Monday, April 23, 12
22. app/representers/message_representer.rb Monday, April 23, 12
23. class MessageRepresenter < Representer::Base namespace :message attributes :id, :title, :body end Monday, April 23, 12
24. class MessageRepresenter < Representer::Base namespace :message attributes :id, :title, :body fields :images aggregate :images, :id do |ids, representer| # This is imaginary code!! <3 RemoteApiClient.find_images(ids).group_by(&:message_id) end def images(message) self.aggregated_images[message['id']] end end Monday, April 23, 12
25. class MessageRepresenter < Representer::Base namespace :message attributes :id, :title, :body belongs_to :user has_many :attachments end Monday, April 23, 12
26. @messages = Message.limit(50) representer = MessageRepresenter.new(@messages) representer.render(:json) Monday, April 23, 12
27. @messages.represent(:json) Monday, April 23, 12
28. { "message": { "id": 1, "title": "OMG YES", "body": "best thing ever" } } Monday, April 23, 12
29. Control Monday, April 23, 12
30. class MessageRepresenter < Representer::Base namespace :message attributes :id, :title, :body belongs_to :user has_many :attachments end class SimpleMessageRepresenter < Representer::Base namespace :post attributes :id, :title, :body end Monday, April 23, 12
31. Testability Monday, April 23, 12
32. describe MessageRepresenter do subject do MessageRepresenter.new([]) end describe "#render" do it "renders to json" do subject.render(:json).should == '[]' end end end Monday, April 23, 12
33. Speed Monday, April 23, 12
34. Benchmarking: simple to_json Average: 26ms Benchmarking: active model serializer Average: 18ms Benchmarking: simple represent Average: 5ms 50 messages with user and one attachment Monday, April 23, 12
35. Average (ms) 5 18 26 to_json Serializers Representers 50 messages with user and one attachment Monday, April 23, 12
36. Talk is cheap, show me the code Linus Torvalds Monday, April 23, 12
37. github.com/futuresimple/representer Monday, April 23, 12
38. Monday, April 23, 12