Intro to Ruby on Rails
- 1. Ruby on RailsJune 17, 2011Elpizo Choi
- 2. What is Ruby on Rails?MVC Framework for building web apps in RubyUses Ruby classes to abstract out the various components of an appConvention over configuration
- 3. Main ComponentsActiveRecord(ORM – think hibernate)ActionController(business logic, routing)ActionView(template parser)Migrations, rake tasks
- 4. Creating a Rails app
- 5. Basic folder structureapps foldercontrollers, models, views – where you’ll spend most your timedatabase.ymlConfigures databaseGemfileConfigures external libraries used in app
- 6. … a little configuration
- 8. Let’s make a model
- 9. ActiveRecord::BaseWhen inherited, maps to table that’s plural of class nameTeam -> teamsBasic methodsTeam.create()Team.find()Team.where().limit().sort().skip().firstTeam.where().limit().sort().skip().all
- 10. …first we need to create table
- 11. …first we need to create table
- 12. …first we need to create tableRakeRuby build tool
- 13. rake –T to see all available tasks
- 14. rake db:migrate will run all database migrations that haven’t been run
- 15. Stores migrations that have already been runCreate a new Team
- 16. QueryingMore in-depth tutorial: http://guides.rubyonrails.org/active_record_querying.html
- 17. The “web” part of web-app
- 18. Let’s get this running
- 19. What happened?
- 20. What happened?
- 21. What happened?config/routes.rb defines how urls are mapped to controllersget “teams/index” is shorthand for:match “teams/index” => “teams#index”, :via => :getMore details: http://guides.rubyonrails.org/routing.htmlRead comments in config/routes.rb
- 22. Let’s make some changes
- 23. Let’s make some changes
- 24. Let’s make some changes
- 25. ControllerLogic to be run every time the mapped route is hit
- 26. All code in the corresponding method will happen as side effects
- 27. Instanced variables set here are available to the templateView.erb is E-Ruby
- 28. Add as extension to allow the default Rails template engine to parse Ruby code inside HTMLViewBasic HTML
- 29. <% %> tag: Ruby code to be run, but not shown
- 30. <%= %>tag: Ruby code to be run and shown
- 31. ^^ important: because everything in Ruby returns something (in this case it’ll be @team object from the block)Creating relationships
- 32. Creating relationshipsCreate the playerAdd foreign key
- 34. Creating relationshipsGotta reload console after changing modelsGet players
- 35. But wait! There’s a shortcut!has_many basically does the following:looks in a table with same name as its argument (players)
- 36. for records whose foreign key column corresponds to the current class (team_id)
- 37. and where the value is the current instance id (1)Likewise…You can either do this….…or this:It’ll accomplish the same thing:
- 38. We can now change our view
- 39. We can now change our view
- 40. More associationsActiveRecord also has shortcuts for:has_and_belongs_to (join tables)Polymorphic associations (belongs_to different objects)http://guides.rubyonrails.org/association_basics.html
- 41. Congratulations!You’ve made your first Rails app
- 42. Additional ResourcesSource code for example_app:https://github.com/fuJiin/example_appSee it live:http://cg-example-app.heroku.com/teams/indexDocumentation and light tutorials:http://guides.rubyonrails.org/More in depth:http://ruby.railstutorial.org/ruby-on-rails-tutorial-book
- 43. Questions?