Ruby on Rails Overview Cheatsheet

Ruby on Rails is a full-stack web application framework following the Model-View-Controller (MVC) pattern and "Convention over Configuration".

Sub-Cheatsheets in this Guide

• Rails Models Cheatsheet
• Rails Controllers Cheatsheet
• Rails Routes Cheatsheet
• Rails Database Migrations Cheatsheet
• Rails Form Helpers Cheatsheet
• Rails View Helpers Cheatsheet
• Rails Internationalization (i18n) Cheatsheet
• Rails Tips & Tricks Cheatsheet

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Common CLI Commands

# Generate a new Rails project
rails new myapp --database=postgresql

# Start development server on localhost:3000
bin/rails server

# Start interactive Rails console
bin/rails console

# Run database migrations
bin/rails db:migrate

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Controller & Action Conventions

class ProjectsController < ApplicationController
  before_action :set_project, only: [:show, :edit, :update, :destroy]

  def index
    @projects = Project.all
  end

  def show
  end

  private

  def set_project
    @project = Project.find(params[:id])
  end
end

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Layouts & Yielding

In app/views/layouts/application.html.erb:

<!doctype html>
<html>
  <head>
    <title><%= content_for?(:title) ? yield(:title) : "Default App" %></title>
    <%= csrf_meta_tags %>
    <%= csp_meta_tag %>
    <%= stylesheet_link_tag "application" %>
    <%= javascript_importmap_tags %>
  </head>
  <body>
    <%= yield %>
  </body>
</html>

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References

• Ruby on Rails Guides