Rails Internals - Write Software, Well

Working with the Rails Instrumentation API

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

How a Ruby Method Becomes a Rails Action: Part One

In this post, we will explore how a simple Ruby method, when added to a controller, becomes an action in Rails, ready to process incoming HTTP requests and send responses. We'll also trace the path of an incoming HTTP request to a Rails controller action.

Rails Internals 7 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 to Access Rails Models in a Rake Task

This article shows how you can access your application models and other constants inside rake tasks by adding the `environment` task as a dependency. We'll also go one level deeper and learn exactly how this task loads the environment by inspecting the Rails source code.

Rails Internals 3 min read

How I Read Rails Source Code

Here're two techniques I've found really helpful for reading the Rails codebase, without getting overwhelmed. If you want to dive into the Rails source code for a deeper understanding, but feel intimidated by the sheer size of the codebase and don't know where to begin, this post is for you.

Rails Internals 13 min read

Custom URL Helpers in Rails with the direct Method

This is the first post in the Campfire deep dive series where we explore the first ONCE product from 37signals to learn and extract useful patterns, ideas, and best practices. This post explores the direct method in the Rails Router that lets you define custom URL helpers for your application.

Rails Internals 6 min read

Prevent Logging Sensitive Data with Rails Parameter Filters

This article explains why you shouldn't log confidential or user-identifiable information and how to filter it using parameter filtering in Rails. We'll also do a deep dive into the Rails source code to learn exactly how Rails implements parameter filters.

Rails Internals 10 min read

💬 Understanding How Rails Environments Work

This post covers the basics of environments in Rails, including what they are, how they work and why they're so important. We'll also take a look behind the scenes and dive into the Rails source code to learn exactly how they're implemented, exploring a few interesting "inquiry" classes in Rails.

Rails Internals 6 min read

Rails Internals: A Deep Dive Into Active Job Codebase

Do you want to understand how Active Job works behind the scenes? Reading and understanding the source code is one of the best ways to learn a framework (or anything). This post breaks it all down for you by tracing the journey of a Rails background job, from its creation to execution.

Rails Internals 10 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