Ruby on Rails - Part 2 - CRUD with Rest standards and Pagination

1) Complete the quick start guide: 

https://localboyfrommadurai.blogspot.com/2021/03/ruby-on-rails-quick-start.html

2) Open Gemfile and the following line

gem 'kaminari'

This library helps for pagination

3) Install the gem:

bundle install

4) Modify app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
    protect_from_forgery with: :null_session
end

Adding this will allow the requests such as PUT, POST and DELETE calls without session authentication.

5) Modify config/routes.rb

Rails.application.routes.draw do
  get 'users(/:page_no)' => 'users#list', :defaults => { :page_no => 1 }
  delete 'users/:user_id' => 'users#delete'
  put 'users/:user_id' => 'users#update'
  post 'users' => 'users#create'
end

6) Modify app/controllers/users_controller.rb

class UsersController < ApplicationController
    def update
        params.require(:name)
        user = User.find(params[:user_id])
        if user
            user.update(name: params[:name])
            render json: {}, status: :ok
            return
        end
        render json: {}, status: :not_found
    end

    def create
        params.require(:name)
        user = User.create({:name => params[:name]})
        render json: user, status: :ok
    end

    def list
        @users = User.page(params[:page_no]).per(5)
        render 'users/list'
    end


    def delete
        User.delete(params[:user_id])
        render json: {}, status: :no_content
    end
end

7) Modify app/views/users/list.html.erb

<h1>Users</h1>

<ul>
  <% @users.each do |user| %>
    <li>
      <div><b>ID: </b><%= user.id %> </div>
      <div><b>Name: </b><%= user.name %> </div>
    </li>
  <% end %>
</ul>

Results:

Happy coding :)