Railsfactory logo

Action Cable

Action Cable is the WebSocket framework in Ruby on Rails that enables real-time features such as live chat, notifications, and activity updates. It seamlessly integrates WebSockets with the rest of the Rails application.

Table of Contents

1. What is Action Cable in Ruby on Rails?
2. Why is Action Cable Useful?
3. How Action Cable Works?
4. Where to Use Action Cable?
5. In Summary

What is Action Cable in Ruby on Rails?

Action Cable is a framework in Rails that integrates WebSockets into your application, allowing for real-time communication between the server and clients. Unlike traditional HTTP requests (which are one-way and require page reloads or polling), Action Cable maintains a persistent connection so that updates can be pushed instantly to the user’s browser.

In simple terms, Action Cable is what powers live features like instant chat, collaborative editing, or notifications in a Rails app.

Why is Action Cable Useful?

Without Action Cable, Rails apps would rely on frequent polling or manual page refreshes to get updates from the server, which is inefficient and resource-heavy. Action Cable solves this by using WebSockets to deliver instant, bidirectional communication.

Benefits include:

  • Real-time user experience (no reloads required).

  • Seamless integration with Rails models, controllers, and routes.

  • Handles multiple connections efficiently.

  • Scales well with Redis for broadcasting.

  • Ideal for building modern interactive applications.

How Action Cable Works?

Action Cable works by opening a WebSocket connection between the client (browser) and the server. Through this connection, the server can broadcast updates to subscribed clients instantly.

Key components:

  • Channels: Similar to controllers in MVC, channels manage WebSocket connections and define how data is transmitted.
  • Subscriptions: Clients subscribe to specific channels to receive relevant updates.
  • Streams: Allow data broadcasting to multiple subscribers at once.
  • Broadcasting: Sends messages from the server to all clients listening to a specific stream.
  • Redis: Often used as a pub/sub backend to handle multiple server instances and scale real-time features.

Example:

  • A chat app uses ChatChannel to stream new messages.

  • When a user sends a message, the server broadcasts it to everyone subscribed to the channel, and it appears instantly on their screen.

Channel (chat_channel.rb):

Glossary_Action cable_1.png

Client-side subscription (chat_channel.js):

Glossary_Action cable_2.png

Broadcasting from Rails:

Glossary_Action cable_3.png

This setup allows instant, real-time message delivery to all users subscribed to the channel.

Where to Use Action Cable?

  • Real-time chat systems (e.g., team collaboration tools, customer support).

  • Live notifications (e.g., friend requests, order status updates).

  • Collaborative apps (e.g., Google Docs-style editing).

  • Live dashboards (e.g., stock prices, sports scores, system monitoring).

  • Multiplayer games or interactive features.

In Summary

Action Cable brings real-time, WebSocket-powered communication to Rails applications. By integrating seamlessly with the Rails stack, it allows developers to build modern, interactive features like chat, notifications, and live dashboards without leaving the Rails ecosystem.