Getting started with Rails (2), Season 2

ROR Lab. Season 2
- The 2nd Round -

Getting Started
with Rails (2)

July 7, 2012

Hyoseong Choi
ROR Lab.

A Blog Project

Post
ny

on
a
m
separate form nested form

e
to form_for

to
ne

m
an
o

y
Comment Tag

form_for ﬁelds_for

ROR Lab.

Using Scaffolding
$ rails generate scaffold Post
name:string title:string content:text

Scaffolding Generator • MVC
• asset
• helper
• test unit
• routing
ROR Lab.

Creating
a Resource w scaffolding
$ rails g scaffold post name title content:text
invoke active_record
create db/migrate/20120705045702_create_posts.rb
create app/models/post.rb
invoke test_unit
create test/unit/post_test.rb
create test/ﬁxtures/posts.yml
invoke resource_route
route resources :posts
invoke scaffold_controller
create app/controllers/posts_controller.rb
invoke erb
create app/views/posts
create app/views/posts/index.html.erb
create app/views/posts/edit.html.erb
create app/views/posts/show.html.erb
create app/views/posts/new.html.erb
create app/views/posts/_form.html.erb
invoke test_unit
create test/functional/posts_controller_test.rb
invoke helper
create app/helpers/posts_helper.rb
invoke test_unit
create test/unit/helpers/posts_helper_test.rb
invoke assets
invoke coffee
create app/assets/javascripts/posts.js.coffee
invoke scss
create app/assets/stylesheets/posts.css.scss
invoke scss
create app/assets/stylesheets/scaffolds.css.scss
ROR Lab.

Running
a Migration
class CreatePosts < ActiveRecord::Migration
  def change
    create_table :posts do |t|
      t.string :name
      t.string :title
      t.text :content

      t.timestamps
    end
  end
end db/migrate/20100207214725_create_posts.rb

ROR Lab.

Running
a Migration
$ rake db:migrate
== CreatePosts: migrating
=========================================
===========
-- create_table(:posts)
-> 0.0019s
== CreatePosts: migrated (0.0020s)

to Where?

ROR Lab.

Adding a Link
<h1>Hello, Rails!</h1>
<%= link_to "My Blog", posts_path %>
app/views/home/index.html.erb

Hello, Rails!
My Blog

ROR Lab.

The Model
class Post < ActiveRecord::Base
attr_accessible :content, :name, :title
end
app/models/post.rb

Rails Active
Model Record

database.yml

ROR Lab.

Adding Validations

class Post < ActiveRecord::Base
  attr_accessible :content, :name, :title

  validates :name, :presence => true
  validates :title, :presence => true,
                    :length => { :minimum => 5 }
end app/models/post.rb
app/models/post.rb

ROR Lab.

Using the Console
$ rails console --sandbox

$ rails c --sandbox
Loading development environment in sandbox (Rails
3.2.6)
Any modiﬁcations you make will be rolled back on exit
1.9.3p194 :001 > Post.all
Post Load (0.1ms) SELECT "posts".* FROM "posts"
=> []
1.9.3p194 :002 > reload!
Reloading...
=> true

ROR Lab.

Listing All Posts
def index
  @posts = Post.all

  respond_to do |format|
    format.html # index.html.erb
    format.json { render :json => @posts }
  end
end
app/controllers/posts_controller.rb

1.9.3p194 :004 > posts = Post.all
=> []
1.9.3p194 :005 > posts.class
=> Array
1.9.3p194 :006 > post = Post.scoped
=> []
1.9.3p194 :007 > post.class
=> ActiveRecord::Relation
ROR Lab.

<h1>Listing posts</h1> Rails makes all of the

<table> instance variables from the
  <tr> action available to the view.
    <th>Name</th>
    <th>Title</th>
    <th>Content</th>
    <th></th>
    <th></th>
    <th></th>
  </tr>

<% @posts.each do |post| %>
  <tr>
    <td><%= post.name %></td>
    <td><%= post.title %></td>
    <td><%= post.content %></td>
    <td><%= link_to 'Show', post %></td>
    <td><%= link_to 'Edit', edit_post_path(post) %></td>
    <td><%= link_to 'Destroy', post, :conﬁrm => 'Are you sure?',
                                     :method => :delete %></td>
  </tr>
<% end %>
</table>

<br />

<%= link_to 'New post', new_post_path %>

app/views/posts/index.html.erb

ROR Lab.

The Layout
: Containers for views

<!DOCTYPE html>
<html>
<head>
  <title>Blog</title>
  <%= stylesheet_link_tag "application" %>
  <%= javascript_include_tag "application" %>
  <%= csrf_meta_tags %>
</head>
<body style="background: #EEEEEE;">

<%= yield %>

</body>
app/views/layouts/application.html.erb

ROR Lab.

Creating New Posts
def new
  @post = Post.new

    format.html # new.html.erb
    format.json { render :json => @post }
  end
end

<h1>New post</h1>

<%= render 'form' %> # using HTTP POST verb

<%= link_to 'Back', posts_path %>
app/views/posts/new.html.erb

ROR Lab.

<%= form_for(@post) do |f| %>
  <% if @post.errors.any? %>
  <div id="errorExplanation">
    <h2><%= pluralize(@post.errors.count, "error") %> prohibited
        this post from being saved:</h2>
    <ul>
    <% @post.errors.full_messages.each do |msg| %>
      <li><%= msg %></li>
    <% end %>
    </ul>
  </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </div>
    <%= f.label :title %><br />
    <%= f.text_field :title %>
  </div>
    <%= f.label :content %><br />
    <%= f.text_area :content %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %> a “Partial” template
app/views/posts/_form.html.erb

ROR Lab.
intelligent submit helper

“create” action

ROR Lab.

def create
  @post = Post.new(params[:post])

    if @post.save
      format.html { redirect_to(@post,
                    :notice => 'Post was successfully created.') }
      format.json { render :json => @post,
                    :status => :created, :location => @post }
    else
      format.html { render :action => "new" }
      format.json { render :json => @post.errors,
                    :status => :unprocessable_entity }
    end
  end
end

ROR Lab.

Show a Post
http://localhost:3000/posts/1

def show
  @post = Post.ﬁnd(params[:id])

    format.html # show.html.erb
    format.json { render :json => @post }
  end
end

ROR Lab.

Show a Post
app/views/posts/show.html.erb

<p id="notice"><%= notice %></p>

<p>
  <b>Name:</b>
  <%= @post.name %>
</p>

<p>
  <b>Title:</b>
  <%= @post.title %>
</p>

<p>
  <b>Content:</b>
  <%= @post.content %>
</p>

<%= link_to 'Edit', edit_post_path(@post) %> |

ROR Lab.

Editing Posts
def edit

<h1>Editing post</h1>

<%= render 'form' %> # using HTTP PUT verb

<%= link_to 'Show', @post %> |
app/views/posts/edit.html.erb

ROR Lab.

Editing Posts
def update

    if @post.update_attributes(params[:post])
      format.html { redirect_to(@post,
                    :notice => 'Post was successfully updated.') }
      format.json { head :no_content }
    else
      format.html { render :action => "edit" }
      format.json { render :json => @post.errors,
                    :status => :unprocessable_entity }
    end
  end
end

ROR Lab.

Destroying a Post
def destroy
  @post.destroy

    format.html { redirect_to posts_url }
    format.json { head :no_content }
  end

ROR Lab.

Git

• Linus Tobalds, 1991
• for source code version control
• local repository

ROR Lab.

Gitosis
• Remote repository
• git clone git://eagain.net/gitosis.git
• git clone git://github.com/res0nat0r/
gitosis.git
• Ubuntu 11.10 -> gitosis package
• Ubuntu 12.04 -> not any more but gitolite
ROR Lab.

Local Machine Git Repository Sever
git@gitserver:project.git

gitosis
gitolite
gitorious
$ git add *
$ git commit
$ git push Origin

ROR Lab.

Getting started with Rails (2), Season 2

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