This document summarizes a presentation about Ruby on Rails given at BarCamp Saigon in December 2010. It introduces Ruby on Rails as a full-stack web framework built on Ruby that follows conventions over configurations and Don't Repeat Yourself (DRY) principles. It discusses starting a new Rails application, using the model, view, controller (MVC) pattern with Active Record to manage data and perform CRUD operations. It also covers routing, controllers, views, mailers and other Rails features.

1. Ruby on Rails 3 December 2010, BarCamp Saigon Nam Ho

2. About me Working at KMS Technology A member of ALT.NET Saigon group 2 @hotrannam

3. Ruby on Rails Web framework Ruby Model-View-Controller pattern Open source Created by David H. Hansson Maintained and developed by Rails core team 3

4. Ruby on Rails Full-stack framework Gives everything you need to create a web app Pretty much forces to use it Convention over configuration Common structures and naming conventions Don’t break conventions unless you really have to Don’t repeat yourself Code is written in just one place Easier for changes Testing 4

5. Confidential 5 Getting started

6. Starting a new app rails new barcamp 6

7. Starting a new app rails server 7

8. Starting a new app 8

9. 9 Quick and easy? More information: http://rubyonrails.org/download

10. Confidential 10 Model

11. Model Contains almost the application logic The heart of application Object Relational Mappings Active Record Data Mapper Mongo Mapper 11

12. Active Record rails g model Article rake db:migrate rails console The generated model class Table and Class name convention The generated database migration file

13. Active Record: CRUD article = Article.new article.title = “Rails 3” article.body = “Barcamp Saigon” article.save Create

14. Active Record: CRUD article = Article.first article = Article.find(id) article = Article.find_by_title(“Rails 3”) articles = Artcile.all() Lots of dynamic finders Read

15. Active Record: CRUD article.title = “Web development with Rails 3” article.save Update

16. Active Record: CRUD article.destroy Article.delete(id) Article.delete_all(“created_at < '2011-01-01'") Delete

17. Active Record: Scope A scope represents a narrowing of a database query articles = Article.published.where_title(“Rails”) Confidential 17

18. Active Record: Validation article.title = nil article.save article.errors.full_messages Confidential 18

19. Active Record: Custom Val. comment = article.comments.create :body => “Great article!” comment.errors.full_messages Confidential 19

20. Active Record: Relationship Confidential 20 1 : 1

21. Active Record: Relationship Confidential 21 1 : n

22. Active Record: Relationship Confidential 22 n : n

23. Active Record: Callbacks before_create after_create before_save after_save before_destroy after_destroy

24. Active Record: Observers When the Model is in a clutter by callbacks Hard to read the Model Observers are callbacks but in a separate class Good at readability Separation of concerns

25. Active Record: Db Migration rails g migration review rake db:migrate

26. Confidential 26 Controller

27. Controller Handle requests and issue responses Pull data from the Model Choose the View to render An action is a public method and/or a corresponding method

28. Controller: Rendering responses A response is rendered with the render command Redirects are made with the redirect_to command An action can only render a response once

29. Controller: Filters before_filter after_filter around_filter Separation of cross-cutting concerns

30. Controller: Example rails g controller article

31. Routing Forward requests to action methods

32. Restful routes and resources

33. View

34. View .html.erb: used for rendering HTML .js.erb: used for AJAX functionality .xml.builder: used for RSS/Atom

35. View Helper methods to generate links, forms, and JavaScript, and to format text Partials are templates that render a part of a page Layouts a templates that contains common page elements

36. Action Mailer Bundler: manages dependencies etc. Confidential 36 Others

37. Confidential 37 Discussion! http://github.com/hotrannam/barcamp