Socket.io under the hood
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This document discusses Socket.io and websockets. It begins by explaining why Socket.io was created, as websockets were not supported by older browsers. It then details the different layers of communication in Socket.io, including the API layer where events are emitted and received, the packet layer which defines the format of messages, and the various underlying protocols like websockets that are used for actual transmission. It encourages further reading on how Socket.io and websockets work under the hood.
![Packet
socket.emit(‘foo’, param1, param2, ...)
# socket.io v0.9.x
packet = {
type: ‘event’
id: ‘unique packet id’
name: ‘foo’
args: [param1, param2, ...]
}
# socket.io v1.0.x
packet = {
type: ‘event’
id: ‘unique packet id’
name: ‘foo’
data: [param1, param2, ...]
}
https://github.com/LearnBoost/socket.io-protocol](https://image.slidesharecdn.com/jsworkshopsocket-140429092006-phpapp01/85/Socket-io-under-the-hood-11-320.jpg)
![Communication Layer
# socket.io v0.9.x
packet = {
type: ‘event’
id: 1
name: ‘foo’
args: [param1, param2, ...]
}
# socket.io v0.9.x
5:1::{“name”:”foo”,”args”:[param1, param2, ...]}
https://github.com/LearnBoost/socket.io-spec](https://image.slidesharecdn.com/jsworkshopsocket-140429092006-phpapp01/85/Socket-io-under-the-hood-12-320.jpg)
Socket.io under the hood
- 1. Hao-kang Den @_hden Socket.io under the hood
- 3. Agenda ● Why socket.io? ● What’s socket.io? What’s websocket? ● Socket.io in detail
- 5. Bi-directional Communication serverclient (1) signal (2) acknowledgement (3) signal (4) acknowledgement
- 6. Why don’t we use websocket? ● Standardized by ○ RFC 6455 ○ W3C ● IE9 says NO
- 7. Why socket.io? + native iOS & Android
- 8. Socket.io Communication Layers API packet communication (ws, jsonp, etc.)
- 10. API # client socket.emit(‘foo’, param1, param2, ...) socket.on ‘bar’, (param1, param2, ...) -> console.log(‘yay got a bar!’) # server socket.on ‘foo’, (param1, param2, ...) -> console.log(‘yay got a foo!’) socket.emit(‘bar’, param1, param2, ...)
- 11. Packet socket.emit(‘foo’, param1, param2, ...) # socket.io v0.9.x packet = { type: ‘event’ id: ‘unique packet id’ name: ‘foo’ args: [param1, param2, ...] } # socket.io v1.0.x packet = { type: ‘event’ id: ‘unique packet id’ name: ‘foo’ data: [param1, param2, ...] } https://github.com/LearnBoost/socket.io-protocol
- 12. Communication Layer # socket.io v0.9.x packet = { type: ‘event’ id: 1 name: ‘foo’ args: [param1, param2, ...] } # socket.io v0.9.x 5:1::{“name”:”foo”,”args”:[param1, param2, ...]} https://github.com/LearnBoost/socket.io-spec
- 13. Further Reading ● http://davidwalsh.name/websocket ● test/spec https://github.com/LearnBoost/socket.io/blob/master/test/socket.io.js ● code https://github.com/LearnBoost/socket.io/blob/master/lib/socket.js read!