MNUG 10.12.15

1. WebSockets
By Bodo Kaiser

2. Preface

3. Specs
Response
Request Request
Socket

4. Upgrade I
Request Response
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept <accept>
Sec-WebSocket-Protocol: <prot1>
GET /<endpoint> HTTP 1.1
Host: example.org
Upgrade: websocket
Connection: Upgrade
Origin: example.org
Sec-WebSocket-Accept <key>
Sec-WebSocket-Version: 13
Sec-WebSocket-Protocol: <prot1>

5. Upgrade II
Key
dGhlIHNhbXBsZSBub25jZQ==
GUID
258EAFA5-E914-47DA-95CA-C5AB0DC85B11
Concat
Hash
sha1
Encode
base64
Accept
s3pPLMBiTxaQ9kYGzzhZRbK+xOo=

6. Frame I
Head Payload
RSV, Opcode
1 Byte
Masked, Length I
1 Byte
Length II
2 Byte
Masking
4 Byte
Length III
8 Byte
Opcodes: Continuation (0x00), Text (0x01), Binary (0x02), Close (0x08), Ping (0x09), Pong (0x0a)

7. Frame II
Length
7 Bit
Length I
< 0x7e
Length II
= 0x7e
Length III
= 0x7f
Masked
for (var i = 0; i < b.length; i++) {
b[i] = b[i] ^ m[i % 4]
}

8. Streams
function Incoming() {
Transform.call(this)
}
Inherits(Incoming, Transform)
Transform.prototype._read = function(chunk, encoding, callback) {
if (!this.header) {
// parse head
}
if (this.header.masked) {
// unmask payload
}
callback(null, chunk)
}

9. Experience

10. Thank You
Bodo Kaiser <i@bodokaiser.io>