A BRIEF OVERVIEW OF RUBY ON RAILS

By Nicolai Reuschling

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
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/