Michael Hartl - Ruby on Rails Tutorial

Welcome to the Ruby on Rails Tutorial! The purpose of this tutorial is to teach you how to develop custom web applications. The resulting skillset will put you in a great position to get a job as a web developer, start a career as a freelancer, or found a company of your own. If you already know how to develop web applications, this tutorial will quickly get you up to speed with Ruby on Rails.

The focus throughout the Ruby on Rails Tutorial is on general skills that are useful no matter which specific technology you end up using. Once you understand how web apps work, learning another framework can be done with much less effort. That being said, the framework of choice in this tutorialnamely, ).

Box 1.1. The many advantages of Rails

Ruby on Rails (or just Rails for short) is a free and open-source web development framework written in the Ruby programming language. Upon its debut, Ruby on Rails rapidly became one of the most popular tools for building dynamic web applications. Rails is used by companies as varied as Airbnb, SoundCloud, Disney, Hulu, GitHub, and Shopify, as well as by innumerable freelancers, independent development shops, and startups.

Although there are many choices in web development, Rails stands apart for its elegance, power, and integrated approach to web applications. Using Rails, even novice developers can build a full-stack web application without ever leaving the frameworka huge boon for people learning web development for the first time. Rails also gives you flexibility going forwardfor example, serving as a great back end if you want to build a single-page application or mobile app sometime down the line.

One big advantage is that Rails is not prone to the new hotness problem that plagues some development communities (notably JavaScript/Node.js), in which a dizzyingly complex set of technologies seems to change every six months. As Rails creator David Heinemeier Hansson once noted:

Back then the complexity merchant of choice was J2EE, but the complaints are uncannily similar to those leveled against JavaScript today The core premise of Rails remains in many ways as controversial today as it was when it premiered. That by formalizing conventions, eliminating valueless choices, and offering a full-stack framework that provides great defaults for anyone who wants to create a complete application, we can make dramatic strides of productivity.

Due in part to this philosophy, Rails has remained so stable at its core much of this tutorial has been the same since the third edition, launched in 2014. The things you learn here wont go out of date soon.

And yet, Rails continues to innovate. For example, the Rails 6 release includes major new features for email routing, text formatting, parallel testing, and multiple-database support. A big part of Rails 6 is being scalable by default, which means that Rails scales no matter how big your app gets. All this while maintaining rock-solid dependabilityindeed, the wildly popular developer platform GitHub, the hugely successful online store-builder Shopify, and the collaboration tool (and very first Rails app) Basecamp all run their sites on the pre-release versions of Rails. This means that new versions of Rails are immediately tested by some of the largest, most successful web apps in existence.

Not bad for a little side project cooked up by a freelance Danish web developer way back in 2004. What was an edgy choice then is an easy choice now: with its proven track-record, productive feature-set, and helpful community, Rails is a fantastic framework for building modern web applications.

There are no formal prerequisites for this book, which contains integrated tutorials for the On the other hand, a surprising number of complete beginners have gotten through this tutorial, so dont let me stop you if youre excited to build web apps.

and its prerequisites a try, then loop back here to see how it goes the second time.

The principal teaching method of this tutorial is building real working software through a series of example applications of increasing sophistication, starting with a minimal hello app (a website which, coincidentally, was also originally written in Rails.

Figure 1.1: The beginning hello app.

Figure 1.2: An intermediate toy app.

Figure 1.3: The final sample app.

Lets get started!

1.1 Up and running

One advantage of using this tutorial is that you can get up and running fast. In particular, the Rails Tutorial has a long-running partnership with AWS Cloud9, a development environment that runs in your browser. The result is a complete system for developing all the software in this tutorial.

This is important because, even for experienced developers, installing Ruby, Rails, and all the associated supporting software can be quite challenging. Compounding the problem is the multiplicity of environments: different operating systems, version numbers, preferences in text editors, etc.

This is why the recommended solution, especially for newer users, is to sidestep most installation and configuration issues by using a cloud integrated development environment, or cloud IDE (). The cloud IDE used in this tutorial runs inside an ordinary web browser, and hence works the same across different platforms. It also maintains the current state of your work, so you can take a break from the tutorial and come back to the system just as you left it.

A second possibility is to set up your native system (Windows, macOS, or Linux) for Rails development. It is definitely recommended that you do this eventually, but it can represent significant overhead, and is likely to require a healthy amount of technical sophistication ( as well.

Box 1.2. Technical sophistication

The Ruby on Rails Tutorial is part of the Learn Enough family of tutorials, which develop the theme of technical sophistication: the combination of hard and soft skills that make it seem like you can magically solve any technical problem (as illustrated in Tech Support Cheat Sheet from xkcd).

Knowing how to code is an important component of technical sophistication, but theres more to it than thatyou also have to know how to click around menu items to learn the capabilities of a particular application, how to clarify a confusing error message by googling it, or when to give up and just reboot the darn thing.

Because web applications have so many moving parts, they offer ample opportunities to develop your technical sophistication. In the context of Rails web development, some specific examples of technical sophistication include making sure youre using the right Ruby gem versions, running bundle install or bundle update, and restarting the local webserver if something doesnt work. (Dont worry if all this sounds like gibberish; well cover everything mentioned here in the course of completing this tutorial.)