在socket出现之前已经有ajax定时请求、长轮询等方案，但都不能满足需求，socket就应用而生了。
socket基本函数socket
总结下常用的socket函数
服务端： socket_create 创建socket设置基本参数
socket_bind 绑定ip和端口号
socket_listen 监听
socket_accept 客户端的连接
socket_read 读取客户端的数据
socket_write 给单独客户端发送数据
socket_close 关闭连接
客户端：socket_create 创建socket设置基本参数
socket_connect 连接socket
socket_write 给服务端发送数据
socket_read 读取服务端数据
socket_close 关闭连接
H5websocket不多说了，上链接
OK，开始贴代码~
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服务端代码：
1 <?php 2 class WS { 3 var $master; 4 var $sockets = array(); 5 var $debug = false;//true为调试模式，输出log日志 6 var $handshake = array(); 7 8 function __construct($address, $port){ 9 $this->master=socket_create(AF_INET, SOCK_STREAM, SOL_TCP) or die("socket_create() failed"); 10 socket_set_option($this->master, SOL_SOCKET, SO_REUSEADDR, 1) or die("socket_option() failed"); 11 socket_bind($this->master, $address, $port) or die("socket_bind() failed"); 12 socket_listen($this->master,20) or die("socket_listen() failed"); 13 14 $this->sockets[] = $this->master; 15 $this->say("Server Started : ".date('Y-m-d H:i:s')); 16 $this->say("Listening on : ".$address." port ".$port); 17 $this->say("Master socket : ".$this->master."\n"); 18 19 while(true){ 20 $socketArr = $this->sockets; 21 $write = NULL; 22 $except = NULL; 23 socket_select($socketArr, $write, $except, NULL); //自动选择来消息的socket 如果是握手 自动选择主机 24 foreach ($socketArr as $socket){ 25 if ($socket == $this->master){ //主机 26 $client = socket_accept($this->master); 27 if ($client < 0){ 28 $this->log("socket_accept() failed"); 29 continue; 30 } else{ 31 $this->connect($client); 32 } 33 } else { 34 $bytes = @socket_recv($socket,$buffer,2048,0); 35 if ($bytes == 0){ 36 $this->disConnect($socket); 37 } 38 else{ 39 $key = array_search($socket, $this->sockets); 40 if (empty($this->handshake) || !isset($this->handshake[$key]) || !$this->handshake[$key]){ 41 $this->doHandShake($socket, $buffer, $key); 42 } 43 else{ 44 $buffer = $this->decode($buffer); 45 echo $buffer.PHP_EOL; 46 $key = array_search($socket, $this->sockets); 47 $arr = $this->sockets; 48 array_shift($arr); 49 foreach ($arr as $s){ 50 $this->send($s, $buffer); 51 } 52 } 53 } 54 } 55 } 56 } 57 } 58 59 function send($client, $msg){ 60 $msg = $this->frame($msg); 61 socket_write($client, $msg, strlen($msg)); 62 } 63 function connect($socket){ 64 array_push($this->sockets, $socket); 65 $this->say("\n" . $socket . " CONNECTED!"); 66 $this->say(date("Y-n-d H:i:s")); 67 } 68 function disConnect($socket){ 69 $index = array_search($socket, $this->sockets); 70 socket_close($socket); 71 $this->say($socket . " DISCONNECTED!"); 72 if ($index >= 0){ 73 echo 'unset index is:'.PHP_EOL; 74 unset($this->sockets[$index]); 75 } 76 } 77 function doHandShake($socket, $buffer, $handKey){ 78 $this->log("\nRequesting handshake..."); 79 $this->log($buffer); 80 list($resource, $host, $origin, $key) = $this->getHeaders($buffer); 81 $this->log("Handshaking..."); 82 $upgrade = "HTTP/1.1 101 Switching Protocol\r\n" . 83 "Upgrade: websocket\r\n" . 84 "Connection: Upgrade\r\n" . 85 "Sec-WebSocket-Accept: " . $this->calcKey($key) . "\r\n\r\n"; //必须以两个回车结尾 86 $this->log($upgrade); 87 $sent = socket_write($socket, $upgrade, strlen($upgrade)); 88 $this->handshake[$handKey]=true; 89 $this->log("Done handshaking..."); 90 return true; 91 } 92 93 function getHeaders($req){ 94 $r = $h = $o = $key = null; 95 if (preg_match("/GET (.*) HTTP/" ,$req,$match)) { $r = $match[1]; } 96 if (preg_match("/Host: (.*)\r\n/" ,$req,$match)) { $h = $match[1]; } 97 if (preg_match("/Origin: (.*)\r\n/" ,$req,$match)) { $o = $match[1]; } 98 if (preg_match("/Sec-WebSocket-Key: (.*)\r\n/",$req,$match)) { $key = $match[1]; } 99 return array($r, $h, $o, $key); 100 } 101 102 function calcKey($key){ 103 //基于websocket version 13 104 $accept = base64_encode(sha1($key . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11', true)); 105 return $accept; 106 } 107 108 function decode($buffer) { 109 $len = $masks = $data = $decoded = null; 110 $len = ord($buffer[1]) & 127; 111 112 if ($len === 126) { 113 $masks = substr($buffer, 4, 4); 114 $data = substr($buffer, 8); 115 } 116 else if ($len === 127) { 117 $masks = substr($buffer, 10, 4); 118 $data = substr($buffer, 14); 119 } 120 else { 121 $masks = substr($buffer, 2, 4); 122 $data = substr($buffer, 6); 123 } 124 for ($index = 0; $index < strlen($data); $index++) { 125 $decoded .= $data[$index] ^ $masks[$index % 4]; 126 } 127 return $decoded; 128 } 129 130 function frame($s){ 131 $a = str_split($s, 125); 132 if (count($a) == 1){ 133 return "\x81" . chr(strlen($a[0])) . $a[0]; 134 } 135 $ns = ""; 136 foreach ($a as $o){ 137 $ns .= "\x81" . chr(strlen($o)) . $o; 138 } 139 return $ns; 140 } 141 142 143 function say($msg = ""){ 144 echo $msg . "\n"; 145 } 146 function log($msg = ""){ 147 if ($this->debug){ 148 echo $msg . "\n"; 149 } 150 } 151 } 152 153 154 new WS('localhost', 4000);
客户端代码（H5）：
1 <html> 2 <head> 3 <title>demo</title> 4 <script src="https://cdn.bootcss.com/jquery/1.9.1/jquery.min.js"></script> 5 </head> 6 <body> 7 <input type="text" id="content"> 8 <input type="button" value="send" id="send"> 9 <script type="text/javascript"> 10 var ws = new WebSocket("ws://localhost:4000"); 11 ws.onopen = function(){ 12 console.log("握手成功"); 13 } 14 ws.onmessage = function(e){ 15 console.log("message:" + e.data); 16 } 17 ws.onerror = function(){ 18 console.log("error"); 19 } 20 $("#send").click(function(){ 21 content = $("#content").val(); 22 console.log(content); 23 ws.send(content); 24 }) 25 </script> 26 </body> 27 </html>
然后执行php demo.php 开启socket（从运维那偷学一招，linux下执行nohup php demo.php &可以在后台执行），浏览器打开多个index.html，就能建立通讯了。
代码解析：
1.属性$sockets数组保存每个accept连接（不知道这么描述对不对）;
2.属性$handshake数组保存连接是否在连接状态;
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