Unraveling the Cable: How ActionCable works

on YouTube ↗34m

" summary

Explains how Action Cable actually wires browsers to Rails: a browser opens a TCP connection, does the HTTP upgrade to 101 Switching Protocols, rack.hijack yields an IO socket, subscriptions flow over that socket, and broadcasts go through Redis Pub/Sub; shows concrete Ruby scripts and browser devtools traces. Claims websockets cut bandwidth overhead—about 80% was HTTP headers in one IoT use case—and demos a chatroom built with these pieces that successfully upgrades, subscribes, publishes, and delivers messages.

AI-written summary · about

" chapters (12)

1. 0:00Intro
2. 0:35About Me
3. 2:34Not magic, not really
4. 4:57What even is Action Cable?
5. 5:55Why use Action Cable?
6. 8:49Action Cable Lifecycle
7. 13:35Client connects to cable
8. 20:40Rack Hijack
9. 22:18Server confirms the connection
10. 25:50Redis Pub/Sub
11. 29:12How WebSockets Work
12. 31:24Sending messages to client

" related talks

• 37mUntangling cables and demystifying twisted transistorsVladimir Dementyev · Rails World 2023
• 39mActionCable for Not-Another-Chat-App-PleaseJesse Wolgamott · RailsConf 2016
• 38mAnycable - Universal Action CableVladimir Dementyev · RubyConf MY 2017
• 28mReal-time collaboration with RailsJP Camara · San Francisco Ruby Conference 2025
• 38mHigh Concurrent Ruby Web Development Without FearDelton Ding · RubyKaigi 2017
• 36mThe pitfalls of realtime-ificationVladimir Dementyev · RailsConf 2022
• 28mReal-Time RailsBrian Cardarella · RailsConf 2013
• 47mActionCable, Rails API and React - Modern Single Page AppsVipul A M · Rails Pacific 2016