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Rails Girls Frankfurt am Main 2013 A BRIEF OVERVIEW OF RUBY ON RAILS

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WHO AM I? Nicolai Reuschling [email protected] software developer, agile coach & lecturer

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

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„DHH“ David Heinemeier Hansson creator of Ruby on Rails

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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)

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

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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

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PROJECT SCAFFOLD

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PROJECT SCAFFOLD

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PROJECT SCAFFOLD

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PROJECT SCAFFOLD

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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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!

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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CONTROLLER handles HTTP requests and sessions collaborates with models pushes information into the views decides, which view and what format to render

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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)

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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

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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

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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MODELS implements „business logic“ (your application idea) associates collaborators and connects data validates information stores and retrieves information from the database

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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

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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

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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MIGRATIONS conﬁguration tool for databases creates/deletes or changes tables may be used to change large sets of data

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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

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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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

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VIEW EXAMPLE (INDEX)

My Weblog

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

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VIEW EXAMPLE (SHOW)

<%= notice %>

<%= @post.title %>

<%= @post.body %>

Comments

<% @post.comments.each do |comment| %>

<%= comment.author_name %> commented on <%= comment.created_at.to_s(:long) %>

<%= comment.body %>

<% end %>

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database Javascript, stylesheet, images MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database Javascript, stylesheet, images MVC architecture

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BIRD‘S EYE VIEW View Assets + Internet Routing Controller Model Database Javascript, stylesheet, images MVC architecture

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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/

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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

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QUESTIONS? ASK THEM! OTHERWISE: HAVE FUN!

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

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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/