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Rails CLI
# Create a new rails app
$ rails new project_name
# Start the Rails server
$ rails s
# Rails console
$ rails c
# Install dependencies
$ bundle install
# View all routes
$ rails routes
# Toggle rails caching
$ rails dev:cache
Rails generators CLI
# CRUD Scaffold (model, migrations, controller, views, test)
rails g scaffold Product name:string price:decimal
# CRUD Scaffold with one to many relationship field
rails g scaffold Invoice customer:references
# Delete scaffold created files
rails destroy scaffold Product
# Controller (name, action1, action2, ...)
$ rails g controller Products index show
# Model, migration and table columns
$ rails g model Product name:string active:boolean
Migration
# Create new table migration
rails g migration Invoices
# Update existing table migration
rails g migration add_comment_to_invoices comment:text
# Run migration
$ rails db:migrate
# Rollback last migration
$ rails db:rollback
# Run database seed code
$ rails db:seed
# Delete and re-create db and run migrations
$ rails db:reset
# Create table migration exemple
create_table :products do |t|
t.string :name
t.decimal :price, precision: 8, scale: 2
t.timestamps
end
# Create table with foreign key
create_table :invoices do |t|
# null: false = dont allow null value in this db field
t.references :customer, null: false, foreign_key: true
t.timestamps
end
# Change table migration exemple
add_column :invoices, :comment, :text
Routes
# Route maps to controller#action
get 'welcome', to: 'pages#home'
# Root page (root_path name helper)
root 'pages#home'
# Named route
get 'exit', to: 'sessions#destroy', as: :logout
# Create all the routes for a RESTful resource
resources :items
# HTTP Verb Path Controller#Action Named Helper
# GET /items items#index items_path
# GET /items/new items#new new_item_path
# POST /items items#create items_path
# GET /items/:id items#show item_path(:id)
# GET /items/:id/edit items#edit edit_item_path(:id)
# PUT /items/:id items#update item_path(:id)
# DELETE /items/:id items#destroy item_path(:id)
# Only for certain actions
resources :items, only: :index
# Resource with exceptions
resources :items, except: [:new, :create]
# Nested resources
resources :items do
resources :reviews
end
# create 7 RESTful for items and reviews
# :reviews will have /items/item:id prefixing each routes
# GET /items/:item_id/reviews reviews#index item_reviews_path
# Dynamic segment: params['id']
get 'products/:id', to: 'products#show'
# Query String: url /products/1?user_id=2
# params will be {'id' 'user_id'}
# Namespace Admin::ArticleController
# and prefix '/admin'
namespace :admin do
resources :articles
end
# only prefix '/admin'
scope '/admin' do
resources :articles, :comments
end
# Redirect
get '/stories', to: redirect('/articles')
Model
# Model validation
validates :title, :description, :image_url, presence: true
validates :email, presence: true, format: { with: /\A[^@\s]+@[^@\s]+\z/, message: 'Must be a valid email address'}
validates :price, numericality: { greater_than_equal_to: 0.01 }
validates :title, uniqueness: true
validates :title, length: { minimum: 3, maximum: 100 }
validates :type, inclusion: types.keys
# Model relationship
belongs_to :customer
# Relation with cascade delete
has_many :invoices, dependent: :destroy
#One to one
has_one :profile
# Hook methods
before_destroy :ensure_not_reference_by_any_invoices
before_save :downcase_email
# create virtual password and password_confirmation
# and bcrypt password_digest
# add method to model: user.authenticate(params[:password])
has_secure_password
Controllers
# Hook before running any code
before_action :set_post, only: [:show, :edit, :update, :destroy]
# If you use Devise (authentification)
before_action :authenticate_user!
# 7 Restfull action short exemple
def index
# Search input name :q
if session[:q].present?
params[:page] = 1
# Create instance variable @
@posts = Post.where "title like ?", "%" + session[:q] + "%"
else
@posts = Post.all
end
@posts = @posts.order("created_at DESC")
# Pagination with will_paginate gem
@posts = @posts.paginate(page: params[:page], per_page: 3)
session[:q] = nil
end
# By convention all action (even empty one)
# run hook before_action and render view template
def show
end
def new
@post = Post.new
end
def edit
end
def create
@post = Post.new(post_params)
if @post.save
redirect_to @post, notice: 'Created successfully!'
else
render :new
end
end
def update
if @post.update(post_params)
redirect_to @post, notice: 'Updated successfully!'
else
render :edit
end
end
def destroy
@post.destroy
redirect_to posts_url, notice: 'Delete successfully!'
end
private
# Use callbacks to share common methods between actions.
def set_post
@post = Post.find(params[:id])
end
# Only allow a list of trusted parameters through.
def post_params
params.require(:post).permit(:title, :body, :image_url)
end
end
# render text
render plain: 'Hello User'
Active Record
# Active record common methods
Article.all
# Throw error if not found
Article.find(params[:id])
# Do not throw error if not found
Article.find_by(product_id: product_id)
@category = Category.find_by!(slug: params['slug']) # Return Not Found Error (404 page in production)
Article.group(:product_id).sum(:quantity)
Article.where('quantity > 1')
Article.where(cat_id: cat_id, model: model)
Article.where(model: model).or(Article.where(cat_id: cat_id))
Article.join(:categories).where(categories: { id: 2 } )
Article.where("title LIKE ?", "%" + params[:q] + "%")
Article.count
Article.first
Article.last
Article.column_names # ['id', 'name', 'price']
Category.delete_all # delete all rows in Category table
product.category = Category.all.sample # random for Faker data
@products = Product.offset(5).limit(10).all # skip 5, take 10
Template
<%# Comment tag %>
<%# Output return expression tag %>
<%= @user.name %>
<%# No output return expression tag %>
<% if @user.name == 'Mike' %>
<%# Layout file : app/view/layouts/application.html.erb %>
<%# In layout file replace expression with page content %>
<%= yield %>
<%# View for the route name helper path %>
<%= link_to 'About', about_path, class: 'nav-link' %>
<%# View for the route name helper path with params %>
<%= link_to 'Item record', item_path(@item) %>
<%# auto object to route map (/products/:id) %>
<%= link_to 'Show', @product %>
<%# Delete link %>
<%= link_to 'Destroy', product, method: :delete, data: { confirm: 'Are you sure?' } %>
<%# Post link %>
<%= button_to 'Add to Cart', line_items_path(product_id: product) %>
# link_to with slot
<%= link_to category_path do %>
<%= @product.category.name %>
<% end %>
<%# Button form %>
<%= button_to 'Logout', logout_path, method: :delete %>
<%# Image asset (app/assets/images) %>
<%= image_tag "rails.png" %>
<%# Format currency %>
<%= number_to_currency(product.price) %>
<%# Safe Html render %>
<%= sanitize(product.description) %>
<%# Enable caching %>
<%= cache @products do %>
<%# Check url %>
<%= request.path.include?('post') ? 'active' : '' %>">
<%# Check current page %>
<%= current_page?('about') ? 'active' : '' %>">
<%# Render shared partial _navbar.html.erb %>
<%= render partial: 'shared/navbar' %>
<%# Render partial _form.html.erb %>
<%= render 'form', product: @product %>
<%# data tables iterations %>
<% @users.each do |user| %> <% end %>
<%# Render a for each _user.html.erb %>
<%= render @users %>
<%# Conditional %>
<% if current_user.signed_in? %>
...
<% else %>
...
<% end %>
<%# Display errors %>
<% if @post.errors.any? %>
<% if form.object.errors.any? %>
<% if @post.errors.empty? %>
<% @post.errors.full_messages.each do |message| %>
<p class='error'><%= message %></p>
<%= user.errors.count %>
<%= post.errors[:description] %>
<%# Flash messages %>
<% flash.each do |msg_type, msg| %>
<div class="alert alert-<%= msg_type %>">
<%= msg %>
</div>
<% end %>
Form
<%# Model form %>
<%= form_with(model: product), local: true do |form| %>
<%= form.label :title %>
<%= form.text_field :title, class: 'form-control' %>
<%= form.submit %>
<% end %>
<%# Generic form %>
<%= form_with url: "/search", method: :get, local: true do |form| %>
<%= form.label :query, "Search for:" %>
<%= form.text_field :query, placeholder: 'search' %>
<%= form.submit "Search", class: 'btn btn-primary' %>
<% end %>
<%# Multi-lines memo %>
<%= form.text_area :description, rows: 10, cols: 60 %>
<%# Collection Select (field, collection, key, value, label) %>
<%= form.collection_select :category_id, Category.all, :id, :name, {include_blank: '- Select a Category -'}, {class: 'form-select'}
<%# Select %>
<%= form.select :type, Customer.types.keys, prompt: 'Select a type' %>
<%= form.select :rating, (1..5) %>
<%# if form in new or edit mode change submit text %>
<%= form.submit @product.new_record? ? 'Create' : 'Update', class: "mt-4 btn btn-primary" %>
Flash, Session and Cookie
# Create flash (reset every new request)
flash[:success] = 'User created with success!'
# Create flash.now (reset every new view render)
flash.now[:error] = 'Please select s user!'
# Create session (reset every browser close)
session[:user_id] = user.id
# Check if session exist
session[:user_id].nil?
# Remove
session.delete(:user_id)
# Remove all
reset_session
# Create cookie (reset at expiration date)
cookies.permanent[:remember_token] = remember_token
# Encrypted cookie
cookies.permanent.encrypted[:user_id] = user.id
# Delete cookie
cookies.delete(:user_id)
Database seed with faker
# bundle install
$ gem 'faker'
# db/seeds.rb
Customer.delete_all
10.times do |n|
customer = Customer.new
customer.name = Faker::Name.name
customer.phone = Faker::PhoneNumber.phone_number
customer.save
end
# Run seed script
$ rails db:seed
Devise Gem (authentification)
# Install
gem devise
bundle install
rails g devise:install # follow on-screen instruction
rails generate devise User
rails db:migrate
# Customize devise login, register, etc. views
rails generate devise:views
# Add in existing controllers
before_action :authenticate_user!
# User shared globals
user_signed_in?
current_user
# Logout link_to exemple
<%= link_to "Logout", destroy_user_session_path, method: :delete %>
Trix Editor
gem ‘image_processing'
rails action_text:install
bundle install
rails db:migrate
# Add to model class
has_rich_text :body
# Template use
<%= form.rich.text_area %>
# actiontext.scss (if using boostrap only)
trix-editor {
&.form-control {
height: auto;
}
}
MISC
# Edit credentials encrypted list (API keys, secrets, etc.)
$ EDITOR="code --wait" bin/rails credentials:edit --environment=development
Clone a Rails project from Github
$ git clone https://github/myprojet…
$ cd projet_name
$ bundle install
$ yarn install --check-files
$ rails dev:cache # not always needed
$ rails db:migrate
$ rails db:seed
$ rails s
Heroku deployment
# Change Gemfile production database to Postgress
group :development do
gem 'sqlite3'
end
group :production do
gem 'pg'
end
# Create git and push to Heroku
$ heroku create
$ git remote
$ bundle install --without production
$ git status
$ git add -A
$ git commit -m 'heroku deployment'
$ git push origin master
$ git push heroku master
$ heroku run rails db:migrate
$ heroku run rails db:seed
# launch the upload site
$ heroku open
Top comments (3)
This is my favorite Rails cheat-sheet. Thank you!
One suggestion: Could you please include the commands for "un-doing" a "generate scaffold," "generate model," "db:migrate," etc.?
Edit: I might as well include those commands here for my own benefit. 😊
Reverse a db:migrate:
rails db:rollback
Reverse a "generate scaffold," a "generate controller," or a "generate model":
rails destroy scaffold Story
rails destroy controller Story
rails destroy model Story
Dude. And I mean 'Dude' inclusively. Where the hell have you been my whole life? But seriously, I just went through a circuitous process to sign up for this site just to tell you what a God/dess you are. Go pat yourself on the back and eat a bowl of iced cream.
Wonderful 👏🏿👏🏿👏🏿👏🏿 Thank you very much.