Understanding Rack, Processes, Threads, Unicorn, Puma, and Action Cable in Restaurants
When writing Controllers and Models on a daily basis, one doesn't often think about what's going on under the hood of Rails. However, when trying to implement "always-on" features like real-time chat and notifications in a Rails app, you suddenly hear things like "Unicorn doesn't play well with this" or "Action Cable is fine." This article will help you understand the underlying mechanisms of Rails, using a restaurant analogy. 1. Rack: A Common Format for Order Slips Rack is a common interface that connects Ruby web servers to web applications. It has a `call(env)` method and is an object that returns `[status, headers, body]`. A Rack app, for example, could be defined as follows: class HelloApp def call(env) [200, {'Content-Type' => 'text/html'}, ["Hello, World!"]] end end
The article explains the underlying mechanisms of Rails, a web application framework, by using a restaurant analogy. It covers Rack, a common interface between Ruby web servers and applications, and how it interacts with middleware and the application layer. The article also discusses the differences between processes and threads, and how they impact the performance of web servers such as Unicorn and Puma.
Additionally, it explains how Action Cable, a feature of Rails, uses an event loop to handle long-lived connections, allowing it to work efficiently with web servers like Unicorn.
Written by urgent.news from Dev.to's report — not a translation of it. Machine-written — may contain errors; check the original before relying on it.
