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关于php:php是如何实现websocket实时消息推送的

WebSocket 是 HTML5 开始提供的一种在单个 TCP 连贯上进行全双工通信的协定。以前的推送技术应用 Ajax 轮询,浏览器须要一直地向服务器发送 http 申请来获取最新的数据,节约很多的带宽等资源。应用 webSocket 通信,客户端和服务端只须要一次握手建设连贯,就能够相互发送音讯,进行数据传输,更实时地进行通信。

一次握手建设 WebSocket 连贯 浏览器先向服务器发送个 url 以 ws:// 结尾的 http 的 GET 申请,响应状态码 101 示意 Switching Protocols 切换协定,服务器依据申请头中 Upgrade:websocket 客户端的申请切换到对应的协定,即 websocket 协定。

响应头音讯中蕴含 Upgrade:websocket,示意它切换到的协定,即 websocket 协定。

响应 101,握手胜利,http 协定切换成 websocket 协定了,连贯建设胜利,浏览器和服务器能够随时被动发送音讯给对方了,并且这个连贯始终继续到客户端或服务器一方被动敞开连贯。为了加深了解,用 websocket 实现简略的在线聊天,先画个时序图,直观感触下流程。

网上有 websocket 在线测试工具,能够间接应用还是挺不便的,http://www.blue-zero.com/WebSocket/

以下是实现的例子,可供参考SocketService.php

<?php
/**
 * Created by cywu
 * Date: 2019/10/18
 * Time: 14:33
 */

class SocketService
{
  private $address = '0.0.0.0';
  private $port = 8080;
  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 协定号码。$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);

          // 在这里写你的业务代码
          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";
        }
      }
    }
  }

  /**
   * 解决握手
   * @param $newClient socket
   * @return int 接管到的信息
   */
  public function handshaking($newClient, $line){$headers = array();
    $lines = preg_split("/rn/", $line);
    foreach($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 Handshakern" .
      "Upgrade: websocketrn" .
      "Connection: Upgradern" .
      "WebSocket-Origin: $this->addressrn" .
      "WebSocket-Location: ws://$this->address:$this->port/websocket/websocketrn".
      "Sec-WebSocket-Accept:$secAcceptrnrn";
    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;
  }

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

$sock = new SocketService();
$sock->run();

前端页面:web.html

<!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:未连贯

1:连贯胜利,可通信

2:正在敞开

3:连贯已敞开或无奈关上
*/

  // 创立一个 webSocket 实例
  var webSocket = new WebSocket("ws://192.168.31.152:8083");


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

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

  // 监听音讯
  webSocket.onmessage = function (event){onMessage(event);
  };


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

  // 敞开监听 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 = ['未连贯','连贯胜利,可通信','正在敞开','连贯已敞开或无奈关上'];
      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>
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