php使用websocket示例详解

下面我画了一个图演示 client 和 server 之间建立 websocket 连接时握手部分，这个部分在 node 中可以十分轻松的完成，因为 node 提供的 net 模块已经对 socket 套接字做了封装处理，开发者使用的时候只需要考虑数据的交互而不用处理连接的建立。而 php 没有，从 socket 的连接、建立、绑定、监听等，这些都需要我们自己去操作，所以有必要拿出来再说一说。

① 和 ② 实际上就是一个 HTTP 的请求和响应，只不过我们在处理的过程中我们拿到的是没有经过解析的字符串。如：

GET /chat HTTP/1.1
Host: server.example.com
Origin: http://www.jb51.com

我们往常看到的请求是这个样子，当这东西到了服务器端，我们可以通过一些代码库直接拿到这些信息。

一、php 中处理 websocket

WebSocket 连接是由客户端主动发起的，所以一切要从客户端出发。第一步是要解析拿到客户端发过来的 Sec-WebSocket-Key 字符串。

GET /chat HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Origin: http://www.jb51.com
Sec-WebSocket-Protocol: chat, superchat
Sec-WebSocket-Version: 13

client 请求的格式

首先 php 建立一个 socket 连接，监听端口的信息。

1. socket 连接的建立

关于 socket 套接字的建立，相信很多大学修过计算机网络的人都知道了，下面是一张连接建立的过程：

// 建立一个 socket 套接字
$master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($master, SOL_SOCKET, SO_REUSEADDR, 1);
socket_bind($master, $address, $port);
socket_listen($master);

相比 node，这个地方的处理实在是太麻烦了，上面几行代码并未建立连接，只不过这些代码是建立一个 socket 套接字必须要写的东西。由于处理过程稍微有复杂，所以我把各种处理写进了一个类中，方便管理和调用。

//demo.php
Class WS {
    var $master;  // 连接 server 的 client
    var $sockets = array(); // 不同状态的 socket 管理
    var $handshake = false; // 判断是否握手
    function __construct($address, $port){
        // 建立一个 socket 套接字
        $this->master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)   
            or die("socket_create() failed");
        socket_set_option($this->master, SOL_SOCKET, SO_REUSEADDR, 1)  
            or die("socket_option() failed");
        socket_bind($this->master, $address, $port)                    
            or die("socket_bind() failed");
        socket_listen($this->master, 2)                               
            or die("socket_listen() failed");
        $this->sockets[] = $this->master;
        // debug
        echo("Master socket  : ".$this->master."\n");
        while(true) {
            //自动选择来消息的 socket 如果是握手 自动选择主机
            $write = NULL;
            $except = NULL;
            socket_select($this->sockets, $write, $except, NULL);
            foreach ($this->sockets as $socket) {
                //连接主机的 client 
                if ($socket == $this->master){
                    $client = socket_accept($this->master);
                    if ($client < 0) {
                        // debug
                        echo "socket_accept() failed";
                        continue;
                    } else {
                        //connect($client);
                        array_push($this->sockets, $client);
                        echo "connect client\n";
                    }
                } else {
                    $bytes = @socket_recv($socket,$buffer,2048,0);
                    if($bytes == 0) return;
                    if (!$this->handshake) {
                        // 如果没有握手，先握手回应
                        //doHandShake($socket, $buffer);
                        echo "shakeHands\n";
                    } else {
                        // 如果已经握手，直接接受数据，并处理
                        $buffer = decode($buffer);
                        //process($socket, $buffer); 
                        echo "send file\n";
                    }
                }
            }
        }
    }
}

上面这段代码是经过我调试了的，没太大的问题，如果想测试的话，可以在 cmd 命令行中键入 php /path/to/demo.php;当然，上面只是一个类，如果要测试的话，还得新建一个实例。

$ws = new WS('localhost', 4000);

客户端代码可以稍微简单点：

var ws = new WebSocket("ws://localhost:4000");
ws.onopen = function(){
    console.log("握手成功");
};
ws.onerror = function(){
    console.log("error");
};

运行服务器代码，当客户端连接的时候，我们可以看到：

2. 提取 Sec-WebSocket-Key 信息

function getKey($req) {
    $key = null;
    if (preg_match("/Sec-WebSocket-Key: (.*)\r\n/", $req, $match)) { 
        $key = $match[1]; 
    }
    return $key;
}

这里比较简单，直接正则匹配，websocket 信息头一定包含 Sec-WebSocket-Key，所以我们匹配起来也比较快捷~

3. 加密 Sec-WebSocket-Key

function encry($req){
    $key = $this->getKey($req);
    $mask = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
    return base64_encode(sha1($key . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11', true));
}

将 SHA-1 加密后的字符串再进行一次 base64 加密。如果加密算法错误，客户端在进行校检的时候会直接报错：

4. 应答 Sec-WebSocket-Accept

function dohandshake($socket, $req){
    // 获取加密key
    $acceptKey = $this->encry($req);
    $upgrade = "HTTP/1.1 101 Switching Protocols\r\n" .
               "Upgrade: websocket\r\n" .
               "Connection: Upgrade\r\n" .
               "Sec-WebSocket-Accept: " . $acceptKey . "\r\n" .
               "\r\n";
    // 写入socket
    socket_write(socket,$upgrade.chr(0), strlen($upgrade.chr(0)));
    // 标记握手已经成功，下次接受数据采用数据帧格式
    $this->handshake = true;
}

这里千万要注意，每一个请求和相应的格式，最后有一个空行，也就是 \r\n，开始测试的时候把这东西给弄丢了，纠结了半天。

当客户端成功校检key后，会触发 onopen 函数：

5. 数据帧处理

// 解析数据帧
function decode($buffer)  {
    $len = $masks = $data = $decoded = null;
    $len = ord($buffer[1]) & 127;
    if ($len === 126)  {
        $masks = substr($buffer, 4, 4);
        $data = substr($buffer, 8);
    } else if ($len === 127)  {
        $masks = substr($buffer, 10, 4);
        $data = substr($buffer, 14);
    } else  {
        $masks = substr($buffer, 2, 4);
        $data = substr($buffer, 6);
    }
    for ($index = 0; $index < strlen($data); $index++) {
        $decoded .= $data[$index] ^ $masks[$index % 4];
    }
    return $decoded;
}

这里涉及的编码问题在前文中已经提到过了，这里就不赘述，php 对字符处理的函数太多了，也记得不是特别清楚，这里就没有详细的介绍解码程序，直接把客户端发送的数据原样返回，可以算是一个聊天室的模式吧。

// 返回帧信息处理
function frame($s) {
    $a = str_split($s, 125);
    if (count($a) == 1) {
        return "\x81" . chr(strlen($a[0])) . $a[0];
    }
    $ns = "";
    foreach ($a as $o) {
        $ns .= "\x81" . chr(strlen($o)) . $o;
    }
    return $ns;
}
// 返回数据
function send($client, $msg){
    $msg = $this->frame($msg);
    socket_write($client, $msg, strlen($msg));
}

客户端代码：

var ws = new WebSocket("ws://localhost:4000");
ws.onopen = function(){
    console.log("握手成功");
};
ws.onmessage = function(e){
    console.log("message:" + e.data);
};
ws.onerror = function(){
    console.log("error");
};
ws.send("李靖");

在连通之后发送数据，服务器原样返回：

二、注意问题

1. websocket 版本问题

客户端在握手时的请求中有Sec-WebSocket-Version: 13，这样的版本标识，这个是一个升级版本，现在的浏览器都是使用的这个版本。而以前的版本在数据加密的部分更加麻烦，它会发送两个key：

GET /chat HTTP/1.1
Host: server.example.com
Upgrade: websocket
Connection: Upgrade
Origin: http://www.jb51.net
Sec-WebSocket-Protocol: chat, superchat
Sec-WebSocket-Key1: xxxx
Sec-WebSocket-Key2: xxxx

如果是这种版本（比较老，已经没在使用了），需要通过下面的方式获取

function encry($key1,$key2,$l8b){ //Get the numbers preg_match_all('/([\d]+)/', $key1, $key1_num); preg_match_all('/([\d]+)/', $key2, $key2_num);
$key1_num = implode($key1_num[0]);
$key2_num = implode($key2_num[0]);
//Count spaces
preg_match_all('/([ ]+)/', $key1, $key1_spc);
preg_match_all('/([ ]+)/', $key2, $key2_spc);
if($key1_spc==0|$key2_spc==0){ $this->log("Invalid key");return; }
//Some math
$key1_sec = pack("N",$key1_num / $key1_spc);
$key2_sec = pack("N",$key2_num / $key2_spc);
return md5($key1_sec.$key2_sec.$l8b,1);
}

只能无限吐槽这种验证方式！相比 nodeJs 的 websocket 操作方式：

//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);

2. 数据帧解析代码

本文没有给出 decodeFrame 这样数据帧解析代码，前文中给出了数据帧的格式，解析纯属体力活。

​​

用PHP的Socket建立自己的聊天室服…

<?php

class patServer{

var $systemVars   =array(
   "appName"   =>"patServer",
   "appVersion"   =>"1.1",
   "author"   =>array("Stephan Schmidt <[email protected]>",)
   );

   var$port   = 10000;

   var$domain   = "localhost";

   var $maxClients = -1;

   var$readBufferSize   = 128;

   var $readEndCharacter ="\n";

   var $maxQueue = 500;

   var$debug   = true;

   var $debugMode = "text";

   var $debugDest = "stdout";

   var$null   = array();

   var $clientFD = array();

   var $clientInfo = array();

   var $serverInfo = array();

   var $clients = 0;

function patServer( $domain = "localhost", $port = 10000 ){
   $this->domain =$domain;
  $this->port   =$port;
  $this->serverInfo["domain"]        = $domain;
  $this->serverInfo["port"]        = $port;
  $this->serverInfo["servername"]    = $this->systemVars["appName"];
  $this->serverInfo["serverversion"] =$this->systemVars["appVersion"];
   set_time_limit( 0 );
}

function setMaxClients( $maxClients ){
  $this->maxClients = $maxClients;
}

function setDebugMode( $debug, $dest = "stdout" ){
   if( $debug === false ){
   $this->debug = false;
    returntrue;
   }
  $this->debug   =true;
  $this->debugMode = $debug;
  $this->debugDest = $dest;
}

function start(){
   $this->initFD =@socket_create(AF_INET, SOCK_STREAM, 0 );
   if(!$this->initFD )
    die("patServer: Could not create socket." );
   // adress may bereused
   socket_setopt($this->initFD, SOL_SOCKET,SO_REUSEADDR, 1 );
   // bind the socket
   if(!@socket_bind($this->initFD, $this->domain,$this->port ) ){
   @socket_close($this->initFD );
    die("patServer: Could not bind socket to".$this->domain." on port".$this->port." (".$this->getLastSocketError($this->initFd )." )." );
   }
   // listen on selectedport
   if(!@socket_listen($this->initFD, $this->maxQueue ))
    die("patServer: Could not listen (".$this->getLastSocketError($this->initFd )." )." );
  $this->sendDebugMessage( "Listening on port".$this->port.". Server started at ".date( "H:i:s",time() ) );
   // this allows the shutdownfunction to check whether the server is already shut down
   $GLOBALS["_patServerStatus"] ="running";
   // this ensures that theserver will be sutdown correctly
   register_shutdown_function(array( $this, "shutdown" ) );
   if( method_exists( $this,"onStart" ) )
   $this->onStart();
  $this->serverInfo["started"] = time();
  $this->serverInfo["status"]  = "running";
   while( true ){
    $readFDs =array();
    array_push($readFDs, $this->initFD );
    // fetchall clients that are awaiting connections
    for( $i = 0;$i < count( $this->clientFD ); $i++)
    if( isset( $this->clientFD[$i] ) )
     array_push( $readFDs, $this->clientFD[$i] );
    // blockand wait for data or new connection
    $ready =@socket_select($readFDs, $this->null, $this->null,NULL );
    if($ready === false ){
    $this->sendDebugMessage( "socket_selectfailed." );
    $this->shutdown();
    }
    // checkfor new connection
    if(in_array( $this->initFD, $readFDs ) ){
    $newClient = $this->acceptConnection($this->initFD );
    // check for maximum amount of connections
    if( $this->maxClients > 0 ){
     if( $this->clients >$this->maxClients ){
      $this->sendDebugMessage( "Too many connections.");
      if( method_exists( $this, "onConnectionRefused" ) )
       $this->onConnectionRefused( $newClient );
      $this->closeConnection( $newClient );
     }
    }
    if( --$ready <= 0 )
     continue;
    }
    // checkall clients for incoming data
    for( $i = 0;$i < count( $this->clientFD ); $i++){
    if( !isset( $this->clientFD[$i] ) )
     continue;
    if( in_array( $this->clientFD[$i], $readFDs )){
     $data = $this->readFromSocket( $i );
     // empty data => connection was closed
     if( !$data ){
      $this->sendDebugMessage( "Connection closed by peer");
      $this->closeConnection( $i );
     }else{
      $this->sendDebugMessage( "Received ".trim( $data )."from ".$i );
      if( method_exists( $this, "onReceiveData" ) )
       $this->onReceiveData( $i, $data );
     }
    }
    }
   }
}

function readFromSocket( $clientId ){
   // start with emptystring
  $data   = "";
   // read data fromsocket
   while( $buf = socket_read($this->clientFD[$clientId],$this->readBufferSize ) ){
    $data .=$buf;
   $endString = substr( $buf, - strlen($this->readEndCharacter ) );
    if($endString == $this->readEndCharacter )
    break;
    if( $buf ==NULL )
    break;
   }
   if( $buf === false )
   $this->sendDebugMessage( "Could not read from client".$clientId." ( ".$this->getLastSocketError($this->clientFD[$clientId] )." )." );
   return $data;
}

function acceptConnection( &$socket ){
   for( $i = 0 ; $i<= count( $this->clientFD ); $i++){
    if( !isset($this->clientFD[$i] ) ||$this->clientFD[$i] == NULL ){
    $this->clientFD[$i] = socket_accept($socket);
    socket_setopt($this->clientFD[$i], SOL_SOCKET,SO_REUSEADDR, 1 );
    $peer_host = "";
    $peer_port = "";
    socket_getpeername($this->clientFD[$i], $peer_host, $peer_port );
    $this->clientInfo[$i] = array(
             "host"   =>$peer_host,
             "port"   =>$peer_port,
             "connectOn" => time()
            );
    $this->clients++;
    $this->sendDebugMessage( "New connection ( ".$i." )from ".$peer_host." on port ".$peer_port );
    if( method_exists( $this, "onConnect" ) )
     $this->onConnect( $i );
    return $i;
    }
   }
}

function isConnected( $id ){
   if( !isset($this->clientFD[$id] ) )
    returnfalse;
   return true;
}

function closeConnection( $id ){
   if( !isset($this->clientFD[$id] ) )
    returnfalse;
   if( method_exists( $this,"onClose" ) )
   $this->onClose( $id );
  $this->sendDebugMessage( "Closed connection (".$id." ) from ".$this->clientInfo[$id]["host"]." onport ".$this->clientInfo[$id]["port"] );
   @socket_close($this->clientFD[$id] );
  $this->clientFD[$id] = NULL;
   unset($this->clientInfo[$id] );
  $this->clients--;
}

function shutDown(){
   if($GLOBALS["_patServerStatus"] != "running" )
    exit;
   $GLOBALS["_patServerStatus"] ="stopped";
   if( method_exists( $this,"onShutdown" ) )
   $this->onShutdown();
   $maxFD = count($this->clientFD );
   for( $i = 0; $i< $maxFD; $i++ )
   $this->closeConnection( $i );
   @socket_close($this->initFD );
  $this->sendDebugMessage( "Shutdown server." );
   exit;
}

function getClients(){
   return$this->clients;
}

function sendData( $clientId, $data, $debugData = true ){
   if( !isset($this->clientFD[$clientId] ) ||$this->clientFD[$clientId] == NULL )
    returnfalse;
   if( $debugData )
   $this->sendDebugMessage( "sending: \"" . $data . "\"to: $clientId" );
   if(!@socket_write($this->clientFD[$clientId], $data ) )
   $this->sendDebugMessage( "Could not write'".$data."' client ".$clientId." (".$this->getLastSocketError($this->clientFD[$clientId] )." )." );
}

function broadcastData( $data, $exclude = array(), $debugData =true ){
   if( !empty( $exclude )&& !is_array( $exclude ) )
    $exclude =array( $exclude );
   for( $i = 0; $i< count( $this->clientFD ); $i++){
    if( isset($this->clientFD[$i] )&&$this->clientFD[$i] != NULL&& !in_array( $i, $exclude )){
    if( $debugData )
     $this->sendDebugMessage( "sending: \"" . $data . "\"to: $i" );
    if(!@socket_write($this->clientFD[$i], $data ) )
     $this->sendDebugMessage( "Could not write'".$data."' client ".$i." (".$this->getLastSocketError($this->clientFD[$i] )." )." );
    }
   }
}

function getClientInfo( $clientId ){
   if( !isset($this->clientFD[$clientId] ) ||$this->clientFD[$clientId] == NULL )
    returnfalse;
   return$this->clientInfo[$clientId];
}

function sendDebugMessage( $msg ){
   if(!$this->debug )
    returnfalse;
   $msg = date( "Y-m-d H:i:s",time() ) . " " . $msg;
   switch($this->debugMode ){
    case"text":
    $msg = $msg."\n";
    break;
    case"html":
    $msg = htmlspecialchars( $msg ) . "<br/>\n";
    break;
   }
   if($this->debugDest == "stdout" || empty($this->debugDest ) ){
    echo$msg;
   flush();
    returntrue;
   }
   error_log( $msg, 3,$this->debugDest );
   return true;
}

function getLastSocketError( &$fd ){
   $lastError = socket_last_error($fd );
   return "msg: " . socket_strerror($lastError ) . " / Code: ".$lastError;
}
function onReceiveData($ip,$data){
  $this->broadcastData($data,array(), true );
}
}
$patServer = new patServer();
$patServer->start();
?>