Preface to the Rails 6 Edition

Rails 1.0 was released in December 2005. In the years since, it has gone from a relatively unknown leading-edge tool to a successful and stable foundation with a large set of associated libraries that others benchmark themselves against.

The book you’re about to read was there from the start, and it has evolved with Rails. It began as a full reference to a small framework when online documentation was scarce and inconsistent. It’s now an introduction to the entire Rails ecosystem—one that leaves you with many pointers to more information that you can explore based on your needs and desires.

This book didn’t just evolve along with Rails: Rails evolved with it. The content in this book has been developed in consultation with the Rails core team. Not only is the code you’ll see in this book tested against each release of Rails, but the converse is also true: Rails itself is tested against the code in this book and won’t be released until those tests pass.

So read this book with confidence that the scenarios not only work but also describe how the Rails developers themselves feel about how best to use Rails. We hope you get as much pleasure out of reading this book as we had in developing it.

This book covers Rails 6. While some of the commands you’ll be using are new, the underlying development model remains the same. Even when new major features are added, such as the ability to process incoming emails with Action Mailbox, changes are evolutionary, not revolutionary.

Rails 6 introduced two major new features and a lot of small improvements. While Rails has always had strong support for sending emails, Rails’ ability to receive emails has been fairly limited until Rails 6. Action Mailbox introduces the concept of Mailboxes, which are controllers for processing incoming emails. You can use mailboxes to access any part of an incoming email, and then trigger any workflow or logic, the same as you would in a normal controller.

Rails 6 also adds seamless support for rich-text editing and management via Action Text. Action Text is an end-to-end integration of the Trix rich text editor to your Rails app using Active Storage. With almost no configuration, you can present a rich text editor to your users, save that rich text, and render it back wherever you want, either as formatted text or plain text. This is a great example of how Rails takes what could be a complicated set of disparate components and brings them together so they work whenever you need them to.

We’ve also updated the setup instructions to focus on Windows, macOS, and Linux. Since Cloud 9 was acquired by Amazon, it’s now a bit more difficult to use as a way to learn Rails. To that end, our setup instructions for Linux now assume you are doing this inside a virtual machine, which should provide a stable, repeatable environment in which to learn Rails. We’ll walk you through that setup if you wish to learn Rails that way.