PHP implements socket push technology

<?php
class WS {
    var $master;
    var $sockets = array();
    var $debug = false;//true为调试模式，输出log日志
    var $handshake = array();

    function __construct($address, $port){
        $this->master=socket_create(AF_INET, SOCK_STREAM, SOL_TCP)     or die("socket_create() failed");
        socket_set_option($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,20)                                or die("socket_listen() failed");
        
        $this->sockets[] = $this->master;
        $this->say("Server Started : ".date(&#39;Y-m-d H:i:s&#39;));
        $this->say("Listening on   : ".$address." port ".$port);
        $this->say("Master socket  : ".$this->master."\n");
        
        while(true){
            $socketArr = $this->sockets;
            $write = NULL;
            $except = NULL;
            socket_select($socketArr, $write, $except, NULL);  //自动选择来消息的socket 如果是握手 自动选择主机
            foreach ($socketArr as $socket){
                if ($socket == $this->master){  //主机
                    $client = socket_accept($this->master);
                    if ($client < 0){
                        $this->log("socket_accept() failed");
                        continue;
                    } else{
                        $this->connect($client);
                    }
                } else {
                    $bytes = @socket_recv($socket,$buffer,2048,0);
                    if ($bytes == 0){
                        $this->disConnect($socket);
                    }
                    else{
                        $key = array_search($socket, $this->sockets);
                        if (empty($this->handshake) || !isset($this->handshake[$key]) || !$this->handshake[$key]){
                            $this->doHandShake($socket, $buffer, $key);
                        }
                        else{
                            $buffer = $this->decode($buffer);
                            echo $buffer.PHP_EOL;
                            $key = array_search($socket, $this->sockets);
                            $arr = $this->sockets;
                            array_shift($arr);
                            foreach ($arr as $s){
                                $this->send($s, $buffer);
                            }
                        }
                    }
                }
            }
        }
    }
    
    function send($client, $msg){
        $msg = $this->frame($msg);
        socket_write($client, $msg, strlen($msg));
    }
    function connect($socket){
        array_push($this->sockets, $socket);
        $this->say("\n" . $socket . " CONNECTED!");
        $this->say(date("Y-n-d H:i:s"));
    }
    function disConnect($socket){
        $index = array_search($socket, $this->sockets);
        socket_close($socket);
        $this->say($socket . " DISCONNECTED!");
        if ($index >= 0){
            echo &#39;unset index is:&#39;.PHP_EOL;
            unset($this->sockets[$index]);
        }
    }
    function doHandShake($socket, $buffer, $handKey){
        $this->log("\nRequesting handshake...");
        $this->log($buffer);
        list($resource, $host, $origin, $key) = $this->getHeaders($buffer);
        $this->log("Handshaking...");
        $upgrade  = "HTTP/1.1 101 Switching Protocol\r\n" .
                    "Upgrade: websocket\r\n" .
                    "Connection: Upgrade\r\n" .
                    "Sec-WebSocket-Accept: " . $this->calcKey($key) . "\r\n\r\n";  //必须以两个回车结尾
        $this->log($upgrade);
        $sent = socket_write($socket, $upgrade, strlen($upgrade));
        $this->handshake[$handKey]=true;
        $this->log("Done handshaking...");
        return true;
    }

    function getHeaders($req){
        $r = $h = $o = $key = null;
        if (preg_match("/GET (.*) HTTP/"              ,$req,$match)) { $r = $match[1]; }
        if (preg_match("/Host: (.*)\r\n/"             ,$req,$match)) { $h = $match[1]; }
        if (preg_match("/Origin: (.*)\r\n/"           ,$req,$match)) { $o = $match[1]; }
        if (preg_match("/Sec-WebSocket-Key: (.*)\r\n/",$req,$match)) { $key = $match[1]; }
        return array($r, $h, $o, $key);
    }

    function calcKey($key){
        //基于websocket version 13
        $accept = base64_encode(sha1($key . &#39;258EAFA5-E914-47DA-95CA-C5AB0DC85B11&#39;, true));
        return $accept;
    }

    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;
    }

    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;
    }

    
    function say($msg = ""){
        echo $msg . "\n";
    }
    function log($msg = ""){
        if ($this->debug){
            echo $msg . "\n";
        } 
    }
}
    

new WS(&#39;localhost&#39;, 4000);

<html>
    <head>
        <title>demo</title>
        <script src="https://cdn.bootcss.com/jquery/1.9.1/jquery.min.js"></script>
    </head>
    <body>
    <input type="text" id="content">
    <input type="button" value="send" id="send">
        <script type="text/javascript">                    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");
            }
            $("#send").click(function(){
                content = $("#content").val();
                console.log(content);
                ws.send(content);
            })        </script>
    </body>
</html>