Rails App From Scratch

Originally posted January 2020, but here it is now!

What they say is true - Ruby on Rails is powerful (and magical!). But to really appreciate that power and magic, you'd have to build an app from the ground up. Let's work through that initial setup of creating folders and files to get a Rails app up and running.

Let's build a coupon application, which stores coupon codes and the stores they belong to.

Create a coupon model in a folder models in a file coupon.rb:

class Coupon < ActiveRecord::Base

end

Create the table and migrate it. Go into your db folder and create a new folder, migrate, and within that folder, a new file, 001_create_coupons.rb:

class CreateCoupons < ActiveRecord::Migration
  def change
    create_table :coupons do |t|
      t.string :coupon_code
      t.string :store

      t.timestamps null: false
    end
  end
end

Migrate by running bin/rails db:migrate RAILS_ENV=test and look at your schema file afterwards to ensure all looks well.

Create the CouponsController located in the controllers folder:

class CouponsController < ApplicationController

end

Create the routes within the folder config and the file routes.rb:

Rails.application.routes.draw do

  resources :coupons, only: [:index, :show, :create, :new]

end

The resources route maps HTTP verbs to controller actions automatically - just the beginning of the magic

Start building out the CouponsController:

class CouponsController < ApplicationController

    def index
        @coupons = Coupon.all
    end

    def show
        @coupon = Coupon.find(params[:id])
    end

    def new

    end

    def create
        @coupon = Coupon.new
        @coupon[:coupon_code] = params[:coupon][:coupon_code]
        @coupon[:store] = params[:coupon][:store]
        @coupon.save
        redirect_to coupon_path(@coupon)
    end

end

At any point, type rails routes in the terminal to see the created routes.

Start mapping out the views within the folder views and folder coupon and your file names will look like this:

index.html.erb
new.html.erb
show.html.erb

The rest is ensuring your views display what you intend them to display, using your console for testing, and seeing what your browser displays - errors, empty content or your actual content.

Cheers to building your own Rails app from scratch, and may you enjoy the power and magic!