Rails Internals

Understanding the Instrumentation API in Rails

The Instrumentation API in ActiveSupport serves a dual purpose. You can use it to implement the observer (pub-sub) pattern, as well as benchmark how long it took to execute some action. In this post, we'll learn almost everything you need to know about the Rails Instrumentation API.

Rails Internals 5 min read

What Happens When You Run Rails dev:cache Command?

You can enable caching in development mode by running the `rails dev:cache` command in terminal. Ever wondered what that command does, and how exactly does it tell Rails to start caching stuff in your application? Let's take a peek behind the curtain to see exactly what's going on.

Rails Internals 2 min read

How to Access a Ruby Hash with both String and Symbol Keys

Sometimes, you receive a Hash key as a method parameter or via user input, and you want to make the Hash understand that key as-is, without worrying if the key is a string or a symbol. ActiveSupport's `HashWithIndifferentAccess` class lets you accomplish this in a convenient way.

Rails Internals 2 min read

How to Debug and Step-Through Rails Codebase

Do you want to read the Rails source code for a deeper understanding of the framework, but feel intimidated by the sheer size of the codebase, or don't know where to start? Start with a specific feature, insert a breakpoint, and step through the method line-by-line. This article shows how.

Rails Internals 3 min read

A Brief Introduction to Rails Initializers: Why, What, and How

At first glance, Rails initializers seem complex, but they're solving a simple, but important problem: run some code after framework and gems are loaded, to initialize the application. This post covers the basics of initializers, including what they are, how they work, and how Rails implements them.

Rails Internals 7 min read

How Module Autoloading Works in Ruby and Rails

Autoloading allows you to speed up the initialization of your library by lazily loading the code only when you need it. This post explains how the autoload method works in Ruby and how Rails overrides this method to provide its own implementation that follows the Rails naming conventions.

Rails Internals 4 min read

Generating Secure Tokens on Your ActiveRecord Models

You must have used the `has_secure_password` macro in Rails. Did you know Rails also provides a `has_secure_token` macro to generate unique tokens on your models? In this article, we'll learn how it works and we'll also see how Rails implements it behind the scenes.

Rails Internals 3 min read

How to Access Hash Values with Methods Using OrderedOptions

Have you ever wanted to create a hash where you could access the values like methods on an object? The OrderedOptions class in Rails lets you do just that. This post shows you how. We'll also explore how Rails implements this feature using Ruby's metaprogramming features.

Rails Internals 5 min read

Readonly Attributes in Rails

In this article, we'll learn how to mark certain attributes as readonly on your active record models, to prevent them from any future updates after the record is created and saved to the database. We'll also learn how Rails implements this feature behind the scenes.

Rails Internals 3 min read

Understanding the Attribute Assignment API in Rails

In this post, we will explore the `AttributeAssignment` module in Rails, which allows you to set an object's attributes by passing in a hash, a feature commonly used by Active Record models. We'll also learn a little metaprogramming along the way.

Rails Internals 3 min read

How Rails Authenticity Tokens Protect Against CSRF Vulnerability

Rails protects your web application from CSRF attack by including an authenticity token in the HTML forms. This token is also stored in the user's session. Upon receiving a request, Rails compares these two tokens to decide if the request is verified.

Rails Internals 6 min read

What Happens When You Call render? Let's Understand the Rails Rendering Process

This article explains the Rails rendering process in the context of returning JSON data from the controller. Hopefully, it will make it clear what really happens when you call the render method from the controller.

Rails Internals 7 min read