A BRIEF OVERVIEW OF RUBY ON RAILS

Transcript

1. Rails Girls Frankfurt am Main 2013 A BRIEF OVERVIEW OF

   RUBY ON RAILS

2. WHO AM I? Nicolai Reuschling nicolai@reuschling.name software developer, agile coach

   & lecturer

3. „MATZ“ Yukihiro Matsumoto inventor, designer & creator of Ruby

4. „DHH“ David Heinemeier Hansson creator of Ruby on Rails

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10. RUBY ON RAILS FRAMEWORK implemented in Ruby collection of great

    solutions for common problems highly opinionated golden path leads to high productivity configurable as well (convention over configuration)

11. PROJECT SCAFFOLD Run in console: rails new rails-girls-weblog-demo

12. SCAFFOLDING code generator tool generates all necessary files model, views,

    controller routing configuration database migration great and easy way to start and build upon Run in console (one line): rails generate scaffold Post title:string body:text

13. PROJECT SCAFFOLD

14. PROJECT SCAFFOLD

15. PROJECT SCAFFOLD

16. PROJECT SCAFFOLD

17. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

18. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

19. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

20. ROUTING too magical and complex to explain in this context

    basically, it decides: what request goes where? splits URI and forwards request to controller, e.g.: /posts/ goes to PostsController /comments/42 goes to CommentsController let‘s assume: it just works!

21. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

22. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

23. CONTROLLER handles HTTP requests and sessions collaborates with models pushes

    information into the views decides, which view and what format to render

24. CONTROLLER ACTIONS index (collection; list of all available resources) show

    (single resource; displays values) new (form for creating a new resource) create (logic to create a new resource) edit (form for updating an existing resource) update (logic to update an existing resource) destroy (logic to delete an existing resource)

25. CONTROLLER EXAMPLE 1/2 # GET /posts # GET /posts.json #

    GET /posts.xml def index @posts = Post.all respond_to do |format| format.html # index.html.erb format.json { render json: @posts } format.xml { render xml: @posts } end end

26. CONTROLLER EXAMPLE 2/2 # GET /posts/1 # GET /posts/1.json #

    GET /posts/1.xml def show @post = Post.find(params[:id]) respond_to do |format| format.html # show.html.erb format.json { render json: @post } format.xml { render xml: @post } end end

27. CONTROLLER EXAMPLE 2/2 # GET /posts/1 # GET /posts/1.json #

    GET /posts/1.xml def show @post = Post.find(params[:id]) respond_to do |format| format.html # show.html.erb format.json { render json: @post } format.xml { render xml: @post } end end

28. CONTROLLER EXAMPLE 2/2 # GET /posts/1 # GET /posts/1.json #

    GET /posts/1.xml def show @post = Post.find(params[:id]) respond_to do |format| format.html # show.html.erb format.json { render json: @post } format.xml { render xml: @post } end end

29. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

30. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

31. MODELS implements „business logic“ (your application idea) associates collaborators and

    connects data validates information stores and retrieves information from the database

32. MODEL EXAMPLE 1/2 class Post < ActiveRecord::Base # attributes attr_accessible

    :body, :title # associations has_many :comments # validations validates :title, presence: true, uniqueness: true, length: { within: 2..100 } validates :body, length: { minimum: 10 } # scopes default_scope order('created_at DESC') end

33. MODEL EXAMPLE 2/2 class Comment < ActiveRecord::Base # attributes attr_accessible

    :author_name, :body, :post_id # associations belongs_to :post # validations validates :author_name, presence: true, length: { maximum: 100 } validates :body, length: { within: 10..1000 } validates :post, associated: true validates :post_id, presence: true # scopes default_scope order('created_at ASC') end

34. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

35. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

36. MIGRATIONS configuration tool for databases creates/deletes or changes tables may

    be used to change large sets of data

37. MIGRATION EXAMPLE class CreatePosts < ActiveRecord::Migration def change create_table :posts

    do |t| t.string :title t.text :body t.timestamps end end end Run in console: rake db:migrate

38. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

39. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

40. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

41. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

42. VIEWS ready HTML page = layout + template + partials

    mixture of HTML tags plus embedded Ruby (ERB) access to all instance variables (@var) set by controller other formats (e.g. JSON, XML) possible as well rendered view is delivered to browser

43. VIEW EXAMPLE (INDEX) <h1>My Weblog</h1> <table> <tr> <th>Title</th> <th>Body</th> <th

    colspan="3">Actions</th> </tr> <% @posts.each do |post| %> <tr> <td><%= post.title %></td> <td><%= truncate(post.body, separator: ' ', omission: '… (continued)') %></td> <td><%= link_to 'Show', post %></td> <td><%= link_to 'Edit', edit_post_path(post) %></td> <td><%= link_to 'Destroy', post, method: :delete, data: { confirm: 'Are you sure?' } %></td> </tr> <% end %> </table>

44. VIEW EXAMPLE (SHOW) <p id="notice"><%= notice %></p> <h1><%= @post.title %></h1>

    <p><%= @post.body %></p> <br /> <h2>Comments</h2> <% @post.comments.each do |comment| %> <h3> <%= comment.author_name %> commented on <%= comment.created_at.to_s(:long) %> </h3> <p><%= comment.body %></p> <% end %>

45. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database MVC architecture

46. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database Javascript, stylesheet, images MVC architecture

47. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database Javascript, stylesheet, images MVC architecture

48. BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model

    Database Javascript, stylesheet, images MVC architecture

49. FEED YOUR BRAIN 1/2 Ruby http://ruby-doc.org/ Ruby on Rails API

    (Official Code Documentation) http://api.rubyonrails.org/ Ruby on Rails Guides http://guides.rubyonrails.org/

50. FEED YOUR BRAIN 2/2 Screencasts http://railscasts.com/ The Pragmatic Bookshelf http://pragprog.com/categories/ruby_and_rails

    Demo Project https://github.com/ncreuschling/rails-girls-weblog-demo

51. QUESTIONS? ASK THEM! OTHERWISE: HAVE FUN!

52. QUESTIONS? ASK THEM! OTHERWISE: HAVE FUN! Thanks!

53. CITATIONS/SOURCES title photo by Jaroen Kransen http://www.flickr.com/photos/jkransen/5231797723/ Matz http://de.wikipedia.org/wiki/Yukihiro_Matsumoto DDH

    http://david.heinemeierhansson.com/