Ruby on Rails Crash Course

Instructor: Grace Tan

Modified from GDI Austin Ruby on Rails track. Major, major props to Cecy Correa of GDI Austin!

Welcome!

INTRODUCE YOURSELF!

Tell us about yourself.

• Who are you?
• What do you hope to get out of the class?
• What's your favorite thing to do in NYC during the Summer?

Ruby review!

• Puts
• Variables
• Arrays
• Hashes
• Classes
• Sub-classes

Rails!

Rails

• Most well-known Ruby gem!
• Invented by DHH
• Came out in 2005
• By 2006, it was already powering Twitter
• Used by companies like Groupon, Funny or Die, Hulu, Airbnb...

Developing with Rails

You can use Cloud9 or Rails "locally" if you already have it installed.

We are going to be using Cloud9, so please sign up!

Why use Rails?

• Tons of included modules and open-source gems to make app building easier
• Well-written documentation
• Convention over configuration
• Uses popular MVC pattern

Popular Rails Gems

• Devise for user authentication.
• Rspec for testing
• React for frontend

Tons of different gems you can install to provide standard functionality in your app!

Documentation

Convention over configuration

Rails already comes "pre-configured" with a lot of stuff so you don't have to spend time doing set-up.

This means you have to follow convention.

Convention over configuration

The downside is — you have to be careful with what you do / move.

For example, you wouldn't want to delete a folder you don't think you're going to use.

MVC

Way to think about the structure of user interfaces.

It separates the data needed to power a UI from the representation of that data.

Model: the brains (like a class!)

Controller: dispatcher

View: what the user sees

MVC as a recipe

Model: ingredients of a recipe

Controller: directions of a recipe

View: picture of a recipe

The Model, View, and Controller all go hand in hand.

Let's get started!

Create a new rails app

	rails new app
					

You just created a new Rails app called "app".

You can call it whatever you want!

	rails new bananas
					

^^That creates a new Rails app called "bananas"

We're done. Go home.

Let's look at the app.

Overwhelmed?

What you need to know

For now, you really only want to be concerned with:

• Controllers: app/controller
• Models: app/models
• Views: app/views
• Database: db/
• Config: config/

Starting your Rails app

For every page of your web app:

1. Data:
   • Generate a Model file
   • Create a Migration
   • Run the Migration
2. Controller:
   • Generate a Controller file
   • Write controller actions

3. View:
   • Generate a View file
   • Write View html/javascript/css
4. Route:
   • Configure routes for your controller actions

Easy peasy!

Data, Controller, View, Route

Let's start coding!

Chirp: Twitter Clone

To create your model and migration file:

					rails generate model Chirp
					
					

To create your database table from the migration:

					rake db:migrate
					
					

Model

Active Record object

Active Record is an "Object Relational Mapping" framework included with Rails. It maps database tables to Ruby objects for us.

To test out the model:

					
rails console 
Chirp.all        #brings up all Chirps. You’ll notice it’s an array!
Chirp.first      #brings up the first Chirp in the database
Chirp.last       #brings up the last Chirp in the database
Chirp.delete_all #deletes all the Chirps in the database (be careful!)
Chirp.delete(x)  #deletes a specific Chirp in the database corresponding to the id.
				
					
					

Controller

					rails generate controller Chirp index
					
					

Rails convention: index, show, update, create, destroy

Views

Rails convention: index.html.erb, edit.html.erb, new.html.erb, show.html.erb

• CSS: Add it to app/assets/stylesheets/chirps.scss
• Javascript (CoffeeScript): Add it to app/assets/javascripts/chirps.coffee

Views

Uses erb! (HTML file with embedded Ruby)

Common Helpers:

• link_to
• form_for
• render

If you want to learn more about how Rails automatically bundles up all these HTML, CSS, and Javascript files: Rails Asset Pipeline

Routes

get ‘chirps/new’, to: ‘chirps#new'
post ‘/chirps’, to: ‘chirps#create’
get ‘chirps/:id’, to: ‘chirps#show’, as: :chirp
delete '/chirps/:id', to: 'chirps#destroy'
root ‘chirps#index 

Running Your App

Start your Rails server using:

					rails server
					
					

Test out your app by navigating to localhost:3000 if developing locally or launch app via Cloud9

Mind blown.

CRUD

What we just built is called "CRUD"

CREATE

READ

UPDATE

DELETE

This is the most common type of app.

Types of CRUD apps

Facebook

Twitter

Pinterest

A blog

Pretty much any app needs basic CRUD

What if I told you there is an easier way?

Rails scaffolding

	rails generate scaffold Chirp username:string post:text
					

This command generates:

• Model
• Migration
• Controller (filled in!)
• Views (filled in!)
• Routes

So why did we just spend so much time doing everything manually?

Because it's important to know the underlying factors of how things work.

Now you can spend your time being more productive!

Magic?

Rails does a ton for you out of the box!

• Migrations generate sql for you
• Server layer parses requests for you
• Router layer knows how to dispatch requests to right controller classes
• Controller layer coordinates between model and views to build right response (MVC!)

Learn more about the Rails request/response lifecycle here