This notes and examples are from Hussein Nasser's Websocket course. link: https://www.youtube.com/watch?v=XgFzHXOk8IQ

WebSocket is a bidirectional communication protocol between client and server over the web.

• bidirectional communication protocol between client and server over the web
• standardized in 2011
• completely compatible with HTTP
• stateful
• built on HTTP 1.1
• it is a stateful
• once the connection is established, either client or server can send data.
• persistent connection
• you can create your own WebSocket or you can use WebSocket library

WebSockets pros and cons

Pros

• full-duplex (no polling)
• HTTP compatible
• firewall friendly (standard)

Cons

• proxying is tricky
• level 7 load balancing is challenging (timeouts)
• stateful, difficult to horizontally scale -> solution is to store the state in db and read if server restarts or client disconnects
• server does not know whether client is disconnected or not

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Chapters

1. What is HTTP?
2. What is a Web Server?
3. Introduction to WebSockets
4. Scaling WebSockets
5. Securing WebSockets
6. Multi-player Game Design with WebSockets
7. Multi-Player Game Building with WebSockets
8. Advanced WebSockets