仓库源文，站点原文

title: 细说WebSocket - Node篇 categories:

• JavaScript
• 前端杂烩
• 网络交互 tags:
• tech
• cnblogs
• websocket warning: true date: 2013-12-20 01:42:00 fromUrl: http://www.cnblogs.com/hustskyking/archive/2013/12/20/websocket-with-node.html from: 博客园

Client：嘿，大哥，有火没？（烟递了过去）
Server：哈，有啊，来~ （点上）
Client：火柴啊，也行！（烟点上，验证完毕）

GET /chat HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Origin: http://example.com
Sec-WebSocket-Protocol: chat, superchat
Sec-WebSocket-Version: 13

HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
Sec-WebSocket-Protocol: chat

mask  = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";  // 这是算法中要用到的固定字符串
accept = base64( sha1( key + mask ) );

1. t = "GhlIHNhbXBsZSBub25jZQ==" + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
   -> "GhlIHNhbXBsZSBub25jZQ==258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
2. s = sha1(t)
   -> 0xb3 0x7a 0x4f 0x2c 0xc0 0x62 0x4f 0x16 0x90 0xf6
      0x46 0x06 0xcf 0x38 0x59 0x45 0xb2 0xbe 0xc4 0xea
3. base64(s)
   -> "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="

var crypto = require('crypto');

require('net').createServer(function(o){
    var key;
    o.on('data',function(e){
        if(!key){
            // 握手
            // 应答部分，代码先省略
            console.log(e.toString());
        }else{

        };
    });
}).listen(8000);

var ws=new WebSocket("ws://127.0.0.1:8000");
ws.onerror=function(e){
  console.log(e);
};

//服务器程序
var crypto = require('crypto');
var WS = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
require('net').createServer(function(o){
    var key;
    o.on('data',function(e){
        if(!key){
            //握手
            key = e.toString().match(/Sec-WebSocket-Key: (.+)/)[1];
            key = crypto.createHash('sha1').update(key + WS).digest('base64');
            o.write('HTTP/1.1 101 Switching Protocols\r\n');
            o.write('Upgrade: websocket\r\n');
            o.write('Connection: Upgrade\r\n');
            o.write('Sec-WebSocket-Accept: ' + key + '\r\n');
            o.write('\r\n');
        }else{
            console.log(e);
        };
    });
}).listen(8000);

//客户端程序
var ws=new WebSocket("ws://127.0.0.1:8000/");
ws.onopen=function(e){
    console.log("握手成功");
};

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-------+-+-------------+-------------------------------+
 |F|R|R|R| opcode|M| Payload len |    Extended payload length    |
 |I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
 |N|V|V|V|       |S|             |   (if payload len==126/127)   |
 | |1|2|3|       |K|             |                               |
 +-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
 |     Extended payload length continued, if payload len == 127  |
 + - - - - - - - - - - - - - - - +-------------------------------+
 |                               |Masking-key, if MASK set to 1  |
 +-------------------------------+-------------------------------+
 | Masking-key (continued)       |          Payload Data         |
 +-------------------------------- - - - - - - - - - - - - - - - +
 :                     Payload Data continued ...                :
 + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
 |                     Payload Data continued ...                |
 +---------------------------------------------------------------+

FIN      1bit 表示信息的最后一帧，flag，也就是标记符
RSV 1-3  1bit each 以后备用的 默认都为 0
Opcode   4bit 帧类型，稍后细说
Mask     1bit 掩码，是否加密数据，默认必须置为1 （这里很蛋疼）
Payload  7bit 数据的长度
Masking-key      1 or 4 bit 掩码
Payload data     (x + y) bytes 数据
Extension data   x bytes  扩展数据
Application data y bytes  程序数据

function decodeDataFrame(e){
  var i=0,j,s,frame={
    //解析前两个字节的基本数据
    FIN:e[i]>>7,Opcode:e[i++]&15,Mask:e[i]>>7,
    PayloadLength:e[i++]&0x7F
  };
  //处理特殊长度126和127
  if(frame.PayloadLength==126)
    frame.length=(e[i++]<<8)+e[i++];
  if(frame.PayloadLength==127)
    i+=4, //长度一般用四字节的整型，前四个字节通常为长整形留空的
    frame.length=(e[i++]<<24)+(e[i++]<<16)+(e[i++]<<8)+e[i++];
  //判断是否使用掩码
  if(frame.Mask){
    //获取掩码实体
    frame.MaskingKey=[e[i++],e[i++],e[i++],e[i++]];
    //对数据和掩码做异或运算
    for(j=0,s=[];j<frame.PayloadLength;j++)
      s.push(e[i+j]^frame.MaskingKey[j%4]);
  }else s=e.slice(i,frame.PayloadLength); //否则直接使用数据
  //数组转换成缓冲区来使用
  s=new Buffer(s);
  //如果有必要则把缓冲区转换成字符串来使用
  if(frame.Opcode==1)s=s.toString();
  //设置上数据部分
  frame.PayloadData=s;
  //返回数据帧
  return frame;
}

//NodeJS
function encodeDataFrame(e){
  var s=[],o=new Buffer(e.PayloadData),l=o.length;
  //输入第一个字节
  s.push((e.FIN<<7)+e.Opcode);
  //输入第二个字节，判断它的长度并放入相应的后续长度消息
  //永远不使用掩码
  if(l<126)s.push(l);
  else if(l<0x10000)s.push(126,(l&0xFF00)>>2,l&0xFF);
  else s.push(
    127, 0,0,0,0, //8字节数据，前4字节一般没用留空
    (l&0xFF000000)>>6,(l&0xFF0000)>>4,(l&0xFF00)>>2,l&0xFF
  );
  //返回头部分和数据部分的合并缓冲区
  return Buffer.concat([new Buffer(s),o]);
}

var ws = new WebSocket("ws://127.0.0.1:8000/"); ws.onopen = function(){ 　　ws.send("握手成功"); };

//服务器程序
var crypto = require('crypto');
var WS = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
require('net').createServer(function(o){
    var key;
    o.on('data',function(e){
        if(!key){
            //握手
            key = e.toString().match(/Sec-WebSocket-Key: (.+)/)[1];
            key = crypto.createHash('sha1').update(key + WS).digest('base64');
            o.write('HTTP/1.1 101 Switching Protocols\r\n');
            o.write('Upgrade: websocket\r\n');
            o.write('Connection: Upgrade\r\n');
            o.write('Sec-WebSocket-Accept: ' + key + '\r\n');
            o.write('\r\n');
        }else{
            // 输出之前解析帧
            console.log(decodeDataFrame(e));
        };
    });
}).listen(8000);

 |Opcode  | Meaning                             | Reference |
-+--------+-------------------------------------+-----------|
 | 0      | Continuation Frame                  | RFC 6455  |
-+--------+-------------------------------------+-----------|
 | 1      | Text Frame                          | RFC 6455  |
-+--------+-------------------------------------+-----------|
 | 2      | Binary Frame                        | RFC 6455  |
-+--------+-------------------------------------+-----------|
 | 8      | Connection Close Frame              | RFC 6455  |
-+--------+-------------------------------------+-----------|
 | 9      | Ping Frame                          | RFC 6455  |
-+--------+-------------------------------------+-----------|
 | 10     | Pong Frame                          | RFC 6455  |
-+--------+-------------------------------------+-----------|

{
    FIN: 1,
    Opcode: 1,
    Mask: 1,
    PayloadLength: 4,
    MaskingKey: [ 159, 18, 207, 93 ],
    PayLoadData: '握手成功'
}

var frame=decodeDataFrame(e);
console.log(frame);
if(frame.Opcode==8){
    o.end(); //断开连接
}

o.write(encodeDataFrame({
    FIN:1,
    Opcode:8,
    PayloadData:buf
}));

ws-URI = "ws:" "//" host [ ":" port ] path [ "?" query ]
wss-URI = "wss:" "//" host [ ":" port ] path [ "?" query ]