Rails - Ruby

Version:

• Rails 5.2.4 on Mac OS X Catalina 10.15.2
• SQLite version 3.29.0

Environment

1. Install Rails on your computer

   # Firstly you should have installed the Ruby 2.6.5
   $ gem install rails -v 5.2.4
   $ rails -v #check your version
   

2. Setting up the Sqlite3( The Sqlite 3 is the defalut database by Rtails)

   $ brew install sqlite3
   

3. Install the Yarn and ChromeDriver

   $ brew install yarn
   $ brew cask install chromedriver
   

1. Hello Rails

1.1 Create Your First Rails Projects

# You should find a empty folder and change the current directory
# 
$ pwd
$ rails new testprojects
$ cd testproject
$ rails db:migrate
$ rails server
$ rails about # show the details of created Rails project
# $ bundle exec rails about

• Finishing the previous steps, you can receive there messages from the terminal.

=> Booting Puma
=> Rails 5.2.4 application starting in development
=> Run `rails server -h` for more startup options
Puma starting in single mode...
* Version 3.12.2 (ruby 2.6.3-p62), codename: Llamas in Pajamas
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://localhost:3000
Use Ctrl-C to stop

• If you want to check the web page you have created by rails new <NAME> command. Type these url http://localhost:3000 in your browser.

• If you want blind the network address, you can specify the Ip address 0.0.0.0.

$ rails server -b 0.0.0.0

• The command generate logs the files and directions. When you create the controller, you can also create the static pages by this command. It means you can build your website by Ruby script.

$ rails generate controller kernel hello goodbye
$ cd /app/controllers & ls 
application_controller.rb	kernel_controller.rb
concerns
$ cd .. && cd ./views/say && ls
goodbye.html.erb	hello.html.erb

• From the previous steps we have created the kernel components for the Rails project.

kernel_controller.rb - the kermel module to control the view layer. The pages the rb file controls are in the path /views/kernel. And the ruby files have created two methods to pass the parameters.

hello.html.erb and goodbye.html.erb are created by the script and they are static page in Rails.

1.2 Pages

Static and Dynamic Pages

• It’s very easy to build the static pages by youself. The only one you have to konw is the location where the static pages store is /public and /app/viewfolder.
• Insert the Ruby sentences into erb files. Now you have built your first dynamic page.

$ vim /app/views/kernel/hello.html.erb
<h1>Say#hello</h1>
<p>
    Find me in app/views/say/hello.html.erb
    The year is <%= @time.year %> # To insert the variables from the controller
</p>

$ vim /app/controller/kernel_controller.rb
class KernelController < ApplicationController
  def hello
    @time = Time.new
  end

  def goodbye
  end
end
# This example indicates the ways for users to control the website pages by ruby files.

2. First Application(Models,Views and Controllers)

Models : maintaining the state of the application. It can handle with the various interface and communication.

View : generate the user interface and is based on the data in the model.

Controller : orchestrate the application and schedule the process of the application.