PHP学院的中学生 2021-09-17 19:37:58 1619次浏览 2条回复 0 1 0

WebSocket 是 HTML5 开始提供的一种在单个 TCP 连接上进行全双工通讯的协议。

WebSocket 使得客户端和服务器之间的数据交换变得更加简单,允许服务端主动向客户端推送数据。

在 WebSocket API 中,浏览器和服务器只需要完成一次握手的动作,两者就形成了一条快速通道创建持久性的连接,两者之间就直接可以数据互相传送。(长连接,循环连接的不算)

现在,很多网站为了实现推送技术,所用的技术都是 Ajax 轮询。轮询是在特定的的时间间隔(如每1秒),由浏览器对服务器发出HTTP请求,然后由服务器返回最新的数据给客户端的浏览器。

这种传统的模式带来很明显的缺点,即浏览器需要不断的向服务器发出请求,然而HTTP请求可能包含较长的头部,其中真正有效的数据可能只是很小的一部分,显然这样会浪费很多的带宽等资源。

php应用实现webSocket更多使用workerman或swoole框架.

serverSocket.php文件

 <?php

class SocketService
{
    private $address;
    private $port;
    private $_sockets;
    public function __construct($address = '', $port='')
    {
            if(!empty($address)){
                $this->address = $address;
            }
            if(!empty($port)) {
                $this->port = $port;
            }
    }

    public function service(){
        //获取tcp协议号码。
        $tcp = getprotobyname("tcp");
        $sock = socket_create(AF_INET, SOCK_STREAM, $tcp);
        socket_set_option($sock, SOL_SOCKET, SO_REUSEADDR, 1);
        if($sock < 0)
        {
            throw new Exception("failed to create socket: ".socket_strerror($sock)."\n");
        }
        socket_bind($sock, $this->address, $this->port);
        socket_listen($sock, $this->port);
        echo "listen on $this->address $this->port ... \n";
        $this->_sockets = $sock;
    }

    public function run(){
        $this->service();
        $clients[] = $this->_sockets;
        while (true){
            $changes = $clients;
            $write = NULL;
            $except = NULL;
            socket_select($changes,  $write,  $except, NULL);
            foreach ($changes as $key => $_sock){
                if($this->_sockets == $_sock){ //判断是不是新接入的socket
                    if(($newClient = socket_accept($_sock))  === false){
                        die('failed to accept socket: '.socket_strerror($_sock)."\n");
                    }
                    $line = trim(socket_read($newClient, 1024));
                    $this->handshaking($newClient, $line);
                    //获取client ip
                    socket_getpeername ($newClient, $ip);
                    $clients[$ip] = $newClient;
                    echo  "Client ip:{$ip}   \n";
                    echo "Client msg:{$line} \n";
                } else {
                    socket_recv($_sock, $buffer,  2048, 0);
                    $msg = $this->message($buffer);
                    //在这里业务代码
                    echo "{$key} clinet msg:",$msg,"\n";
                    fwrite(STDOUT, 'Please input a argument:');
                    $response = trim(fgets(STDIN));
                    $this->send($_sock, $response);
                    echo "{$key} response to Client:".$response,"\n";
                }
            }
        }
    }

    /**
     * 握手处理
     * @param $newClient socket
     * @return int  接收到的信息
     */
    public function handshaking($newClient, $line){

        $headers = array();
        $lines = preg_split("/\r\n/", $line);
        foreach($lines as $line)
        {
            $line = chop($line);
            if(preg_match('/\A(\S+): (.*)\z/', $line, $matches))
            {
                $headers[$matches[1]] = $matches[2];
            }
        }
        $secKey = $headers['Sec-WebSocket-Key'];
        $secAccept = base64_encode(pack('H*', sha1($secKey . '258EAFA5-E914-47DA-95CA-C5AB0DC85B11')));
        $upgrade  = "HTTP/1.1 101 Web Socket Protocol Handshake\r\n" .
            "Upgrade: websocket\r\n" .
            "Connection: Upgrade\r\n" .
            "WebSocket-Origin: $this->address\r\n" .
            "WebSocket-Location: ws://$this->address:$this->port/websocket/websocket\r\n".
            "Sec-WebSocket-Accept:$secAccept\r\n\r\n";
        return socket_write($newClient, $upgrade, strlen($upgrade));
    }

    /**
     * 解析接收数据
     * @param $buffer
     * @return null|string
     */
    public function message($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;
    }

    /**
     * 发送数据
     * @param $newClinet 新接入的socket
     * @param $msg   要发送的数据
     * @return int|string
     */
    public function send($newClinet, $msg){
        $msg = $this->frame($msg);
        socket_write($newClinet, $msg, strlen($msg));
    }

    public 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;
    }

    /**
     * 关闭socket
     */
    public function close(){
        return socket_close($this->_sockets);
    }
}

$sock = new SocketService('127.0.0.1','9000');
$sock->run();

web.html 文件

 <!doctype html>
<html lang="en">
 <head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width,initial-scale=1, maximum-scale=1, user-scalable=no">
  <title>websocket</title>
 </head>
 <body>
 <input id="text" value="">
 <input type="submit" value="send" onclick="start()">
 <input type="submit" value="close" onclick="close()">
<div id="msg"></div>
 <script>
    /**
      *0:未连接
      *1:连接成功,可通讯
      *2:正在关闭
      *3:连接已关闭或无法打开
      */
    //创建一个webSocket 实例
    var webSocket  = new  WebSocket("ws://127.0.0.1:9000");


    webSocket.onerror = function (event){
        onError(event);
    };

    // 打开websocket
    webSocket.onopen = function (event){
        onOpen(event);
    };

    //监听消息
    webSocket.onmessage = function (event){
        onMessage(event);
    };


    webSocket.onclose = function (event){
        onClose(event);
    }

    //关闭监听websocket
    function onError(event){
        document.getElementById("msg").innerHTML = "<p>close</p>";
        console.log("error"+event.data);
    };

    function onOpen(event){
        console.log("open:"+sockState());
        document.getElementById("msg").innerHTML = "<p>Connect to Service</p>";
    };

    function onMessage(event){
        console.log("onMessage");
        document.getElementById("msg").innerHTML += "<p>response:"+event.data+"</p>"
    };

    function onClose(event){
        document.getElementById("msg").innerHTML = "<p>close</p>";
        console.log("close:"+sockState());
        webSocket.close();
    }

    function sockState(){
        var status = ['未连接','连接成功,可通讯','正在关闭','连接已关闭或无法打开'];
            return status[webSocket.readyState];
    }

    function start(event){
        console.log(webSocket);
        var msg = document.getElementById('text').value;
        document.getElementById('text').value = '';
        console.log("send:"+sockState());
        console.log("msg="+msg);
        webSocket.send("msg="+msg);
        document.getElementById("msg").innerHTML += "<p>request"+msg+"</p>"
    };

    function close(event){
        webSocket.close();
    }
 </script>
 </body>
</html>

运行操作结果:

准备工作开启扩展: php需要打开websocket的扩展,在php安装目录下的php.ini文件 extension=php_sockets.dll

先执行脚本 例如: php -q serverSocket.php 后执行页面 例如: http://web.html

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