Hello World from OSS Silicon Valley

_ Prerequisite

• Ubuntu Server (You can refer Overall/UbuntuServer)
• RVM (You can refer Overall/RVM)

_ Install&Setup

Step.1

Check if the rails has already been installed.

$ rails --version

Step.2

If the rails has not been installed yet, execute the following command

$ gem install rails

_ HowToUse

_ Create new application

Step.1

Create new application.

$ rails new <Application Name>

Step.2| Open the Gemfile and append the following lines.

$ vi Gemfile

gem ‘execjs’
gem ‘therubyracer’

$ bundle install

Step.3

Launch application.

$ cd <Application Name>
$ rails server

Step.4

Access the following page.

http://localhost:3000/

When you are setting portforwarding with rails4.2, localhost doesn't work by default. If you want to do port-forwarding, put the following option.

$ rails start -b 0.0.0.0

http://stackoverflow.com/questions/27799260/rails-4-2-server-port-forwarding-on-vagrant-does-not-work

_ Create sample program with Scaffold

Step.1

Create objects withs scaffold.

$ rails generate scaffold <Object Name>

(Example)

$ rails generate scaffold TestObject name:string

Step.2

Prepare database.

$ rake db:migrate

Step.3

Launch the server and access http://<IP address>:3000/<Object Name>

Now you have a page which maintains data stored in Sqlite DB.

_ Create Say Hello program

Step.1

Create controller and view files.

$ rails generate controller <Controller Name> <Method(View)> <Method(View)>

(Example)

$ rails generate controller Say hello goodbye

Step.2

Access the following page.

http://localhost:3000/say/hello/

#ref(): File not found: "CreateApplication_fig2.png" at page "HowToUse/RubyOnRails/4.1"

_ Get data from RESTful service

Step.1

Edit controller.

$ vi app/controller/<Controller file>

   require 'open-uri'
   require 'json'

   res = open('<URL>')
   code, message = res.status

   if code == '200'

     @result = JSON.parse(res.read)
   end 

Step.2

Put it to view file.

$ vi app/view/<View file>

<table>
<% @result.each do |data| %>
 <tr>
 <td><%= data['<Key#1>'] %></td>
 <td><%= data['<Key#2>'] %></td>
 </tr>
<% end %>
</table>

_ Change table structures

Step.1

Create migration script

$ rails g migration <Migration Script Name>

(Example)

$ rails g migration AddColumnUsers

Step.2

Edit migration script.

$ vi db/migrate/<Migration Script File Name>

(Example - change column)

$ rails g migration db/migrate/20150927000024_add_column_workorders.rb

class AddColumnWorkorders < ActiveRecord::Migration
  def change
    add_column :<table name>, :<column name>, :<data type>
    remove_column :<table name>, :<column name>
  end
end

(Example - add foreign key)

class AddForeignKeyStatements < ActiveRecord::Migration
  def change
    add_foreign_key :<referring table name>, :<referred table name>
  end
end

If you set "statements" as referring table, and "calendars" as refered table, then your calendar_id in statements table will be set for foreign_key.

(Example - remove foreign key)

class RemoveForeignKeyStatements < ActiveRecord::Migration
  def change
    remove_foreign_key :<referring table name>, :<referred table name>
  end
end

Step.3

Setup database

$ rake db:create
$ rake db:migrate

Step.4

Edit index.html.erb

$ vi app/views/<table>/index.html.erb

Step.5

Edit _form.html.erb

$ vi app/views/<table>/_form.html.erb

<%= f.label :<column> %>
<%= f.text_field :<column> %>

Step.6

Edit conroller. After Rails is version up to 4.x, we can't use "attr_accessible", so we need to define as below instead.

$ vi app/controller/<table name>_controller.rb

def create
  attr = params.require(:<table name>).permit(:<column name>)
  @<table name> = <table name>.new(attr)

_ DB Migration

(Initilization)

$ rake db:migrate

(Rollback)

$ rake db:rollback

(DB Dump)

$ rake db:schema:dump

(Drop Database)

$ rake db:drop

(Load Dump file)

$ rake db:setup

(Reset DB)

$ rake db:reset

This is equivalent to "rake db:drop" with "rake db:setup".

_ Testing

Step.1

Prepare test script.

default script)

require 'test_helper'

class <Class Name>ControllerTest < ActionController::TestCase
  # test "the truth" do
  #   assert true
  # end
end

Step.2

Prepare test environment.

$ rake db:test:prepare

Step.3

Execute test script.

$ rake test

_ Author

S.Yatsuzuka