Websockets enable bidirectional communication over HTTP, allowing for more dynamic interactions compared to traditional HTTP requests. This document discusses various implementations of Websockets in Node.js, such as `socket.io` and `ws`, highlighting their performance, API design, and reliability. Additionally, it provides example projects like a simple websocket chat app and a geolocation tracking tool.

1. WebSockets
by Bodo Kaiser

2. What are WebSockets?
WebSockets allow bidirectional communication over HTTP!

3. HTTP
Server
Client
GET / HTTP/1.1
Host: localhost
Accept: */*
HTTP/1.1 200 OK
Content-Type: text/plain
Content-Length: 12

4. WS
Server
Client
GET / HTTP/1.1
Host: localhost
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: …
Sec-WebSocket-Version:13
HTTP/1.1 101 Switching…
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: …

5. Frame Encoding
1000 0001 0000 0101 0100 1000 0110 0101 0111 1001
PayloadHeader
H e y
F
I
N
R
S
V
OP
CODE
M
A
S
K
LENGTH
Extended Length Masking

6. WebSockets in node.js
socket.io by learn boost
fallback support, high level api (e.g. events)
!
ws by einaros
„fastest“ websocket implementation

7. Walve
- socket.io by learn boost
not working, using xhr fallback all the time, cannot read code for PR
!
- other ws implementations
awful API design, also bad to read
1. Follows node’s core conventions
2. Uses node’s TransformStreams
3. Written in readable JavaScript

8. Design
http.Server
„upgrade“ Event
walve.Server
walve.Response
walve.Socket
walve.Socket
walve.Incoming walve.Outgoing
„response“ Event
Some Router /
Web Framework

9. Code Examples
Visit http://github.com/bodokaiser/node-walve !
!
!
Do not forget to leave a Start :)

10. Performance (Hello World)
Hello World
0,000
1,000
2,000
3,000
4,000
5,000
ws walve

11. Performance (Small Image)
Small Image
60,000
70,000
80,000
90,000
100,000
110,000
ws walve

12. Performance (Large Image)
Large Image
Werteachse
2000,000
2400,000
2800,000
3200,000
3600,000
4000,000
4400,000
4800,000
5200,000
5600,000
6000,000
ws walve

13. Performance (Memory Consumption)
Memory Consumption
0,0
100,0
200,0
300,0
400,0
500,0
walve ws

14. Further Thoughts
1. Reliability
!
2. Extendability
!
3. Future development
!
4. Mobile Usage (ProTip)

15. Examples
Messenger
!
Simple WebSocket Chat with Image support.
Nearby
!
Realtime Tracking with Google Maps and
Geolocation.
!
http://github.com/bodokaiser/messenger
http://github.com/bodokaiser/nearby

16. Thanks and Q&A
Follow me on twitter @bodojs
!
Star my projects on github github.com/bodokaiser