Preface
Do you ever get the feeling that you know a topic is important and that you should know well, but you only understand it superficially? Ever since I got into Rails, I've had that feeling with the Rails router.
Coming from ASP.NET, I knew the concept of routing and got comfortable with the router after reading the docs. However, at the back of my mind, I've always had that nagging feeling that I don't REALLY understand the complete picture. I could make the basic routes and resources to get by for the simple CRUD tasks, but whenever I wanted to do something complicated, I found myself fumbling in dark.
Well, after over a year of fumbling and trying to skim the docs and StackOverflow to just learn enough to get by, I decided to dig deeper and REALLY understand how Routing works in Rails.
I've tried to summarize everything I learned in this handbook. It's more than 12,000 words, so don't expect to finish it in one sitting. However, if you can stick through it and read it till the end, I can pretty much guarantee that you'll have a much better understanding of how routing works in Rails. You'll also learn a few nice tips and tricks to clean up and simplify your existing routes right away.
What's the Plan?
We'll start with the basics, by understanding the purpose of routing in web applications and the role of the Rails router. Then we'll open the hood (i.e. the Rails codebase) and take a peek behind the scenes to understand how Rails implements the routing mechanism.
Then, we'll learn about the match method, which forms the core of most of the routing shorthand methods in Rails, such as get, post, etc. It leads us into covering a few fundamental routing topics such as segment keys and named routes.
Once we've learned the fundamentals, we'll be ready to tackle the practical routing topics, which you'll use day-to-day in your Rails apps. They include the concept of resources and RESTful routes, which drastically reduce the amount of code you write by following convention-over-configuration. We'll wrap up by learning the syntactic sugar provided by router to make it easy to create more expressive routes.
As it goes with all the posts on the Write Software, Well blog, I'm writing this guide for me, to clarify my understanding and act as a reference for the future me, but I really hope that you, the reader, find my writing useful in gaining a deeper understanding of the Rails Router.
There's a little metaprogramming involved along the way, but don't worry, it's actually very simple to understand. If you need a quick primer on metaprogramming, check out my notes on the Metaprogramming Ruby book.
Sounds interesting? Let's get started. We've got a lot of ground to cover.