2010 07-20 TDD with ActiveResource
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The document discusses the development of API-based client/server applications using TDD and ActiveResource, highlighting trade-offs between database-backed and API-backed applications. It provides coding examples and explores testing methods with RSpec and mocks in TDD. Additionally, it mentions the use of Distributed Ruby (DRB) for remote method invocation and outlines details about a business conference event for Rails and web app professionals.
2010 07-20 TDD with ActiveResource
- 1. API-based client/serverAPI-based client/server applications with TDD andapplications with TDD and ActiveResourceActiveResource Wolfram ArnoldWolfram Arnold www.rubyfocus.bizwww.rubyfocus.biz In collaboration with:In collaboration with: Kurt SnyderKurt Snyder papercheck.compapercheck.com marakana.commarakana.com
- 4. Tradeoffs?Tradeoffs? DB-backed Fast ActiveRecord well developed Complex relationships possible Limited scalability—tight coupling API-backed Extra network & server latency Complex relationships more difficult Scales well to different front-ends—loose coupling
- 5. Client Application (Flash or JS) Frontend ScalabilityFrontend Scalability Client Application ActiveResource Server Application API JSON DB SQL Client Application (Mobile)
- 6. Rails ActiveResourceRails ActiveResource Model objects that behaves ActiveRecord objects Maps CRUD operations to RESTful API No Associations No Validations (added in Rails 3) Rougher around the edges than ActiveRecord
- 7. From CRUD to RESTFrom CRUD to REST class Person < ActiveResource::Base site “http://server.example.com/people” format :json end Person.create(:name => “Joe”) → POST /people, {'name':'Joe'} Person.find(4) → GET /people/4
- 8. Resourceful RoutesResourceful Routes map.resources :people (in config/routes.rb) people_path, people_url “named route methods” GET /people → “index” action POST /people → “create” action new_person_path, new_person_url GET /people/new → “new” action edit_person_path, edit_person_url GET /people/:id/edit → “edit” action with ID person_path, person_url GET /people/:id → “show” action with ID PUT /people/:id → “update” action with ID DELETE /people/:id → “destroy” action with ID
- 9. Hyperactive ResourceHyperactive Resource http://github.com/taryneast/hyperactiveresource Adds Associations Supports nested routes /people/5/addresses/3 But: Cannot mix nested and non-nested routes for the same resource Adds Validations
- 10. Let's do some codingLet's do some coding Demo RESTful Person Server API with JSON HyperactiveResource-based client
- 11. TDD anyone?TDD anyone? DB Application ActiveRecord SQL RSpec model tests with fixtures, factories Test Database with transaction support
- 12. TDD ActiveRecord StyleTDD ActiveRecord Style it “should create the object” do lambda { Person.create(:first_name => “Joe”) }.should change(Person, :count).by(1) end it “should destroy the object” do p = Factory.create(:person) lambda { p.destroy }.should change(Person, :count).by(-1) end
- 13. API-backedAPI-backed Client Application ActiveResource Server Application API JSON DB SQL RSpec model test Test Database on Test Server instance!
- 14. Mocks anyone?Mocks anyone? FakeWeb gem: http://github.com/chrisk/fakeweb FakeWeb.register_uri(:get, "http://server.example.com/people", :body => "Hello World!") Body is the mock object. It should simulate the server response. Great solution if it's a 3rd party server.
- 15. Problems with Mocks?Problems with Mocks? If the server code is under our control... What happens if the server API changes but the mock doesn't? What process keeps the simulated server responses and the actual API in sync? Better ideas?
- 16. Beyond MocksBeyond Mocks Remote Specs Rely on remote server running (in test environment) Mechanism to set up data Mechanism to inspect data Mechanism to clean up data
- 17. Distributed Ruby “DRb”Distributed Ruby “DRb” Client Application DRb Client Server Application DRb Server DRb Remote Method Invocation foo(args) foo(args)
- 18. Demo DRb
- 19. Gotcha'sGotcha's ActiveResource::Base.include_root_in_json after_initialize hook for starting DRb server :id problem for Objects, via DRb Need to run server in test mode Ideas/Questions: Front Object in DRb? rake task to start/stop server—reliably find process? DRb port inflation—better way?
- 20. SummarySummary Server application with REST controller Client application with ActiveResource Use DRb to: test objects inquire “actual” data TDD with ActiveResource
- 21. BizConfBizConf Aug 4-6, 2010 Amelia Island, FL Discount code: WOLF for 43% off http://bizconf.org? coupon=WOLF Rails & Web App Professionals, Entrepreneurs, Consultants Small group Network with Who's Who Organized by Obie Fernandez of Hashrocket Highlight: David Allen