Chapter 18
Finding Your Way Around Rails

Having survived our Depot project, you are now prepared to dig deeper into Rails. For the rest of the book, we’ll go through Rails topic by topic (which pretty much means module by module). You have seen most of these modules in action before. We’ll cover not only what each module does but also how to extend or even replace the module and why you might want to do so.

The chapters in Part III cover all the major subsystems of Rails: Active Record, Active Resource, Action Pack (including both Action Controller and Action View), and Active Support. This is followed by an in-depth look at migrations.

Then we are going to delve into the interior of Rails and show how the components are put together, how they start up, and how they can be replaced. Having shown how the parts of Rails can be put together, we’ll complete this book with a survey of a number of popular replacement parts, many of which can be used outside of Rails.

We need to set the scene. This chapter covers all the high-level stuff you need to know to understand the rest: directory structures, configuration, and environments.