Bagaimana untuk Membina Pelayan WebSocket dalam PHP?

Cara Membuat Pelayan WebSocket dalam PHP

Mencipta pelayan WebSocket boleh menjadi tugas yang mencabar, terutamanya jika anda menghadapi kod yang sudah lapuk atau dokumentasi yang tidak lengkap . Berikut ialah penyelesaian terperinci untuk membimbing anda melalui proses:

Kod Bahagian Pelayan:

<?php

set_time_limit(0);
ob_implicit_flush();

$master = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
socket_set_option($master, SOL_SOCKET, SO_REUSEADDR, 1);
socket_bind($master, "localhost", 12345);
socket_listen($master, 20);

$sockets = array($master);
$users = array();

while (true) {
  $changed = $sockets;
  socket_select($changed, $write=NULL, $except=NULL, NULL);
  foreach ($changed as $socket) {
    if ($socket == $master) {
      $client = socket_accept($master);
      if ($client < 0) {
        echo "socket_accept() failed\n";
        continue;
      } else {
        connect($client);
      }
    } else {
      $bytes = @socket_recv($socket, $buffer, 2048, 0);
      if ($bytes == 0) {
        disconnect($socket);
      } else {
        $user = getuserbysocket($socket);
        if (!$user->handshake) {
          dohandshake($user, $buffer);
        } else {
          process($user, $buffer);
        }
      }
    }
  }
}

function connect($socket) {
  global $sockets, $users;
  $user = new User();
  $user->id = uniqid();
  $user->socket = $socket;
  array_push($users, $user);
  array_push($sockets, $socket);
  echo $socket." CONNECTED!\n";
}

function disconnect($socket) {
  global $sockets, $users;
  $found = null;
  $n=count($users);
  for ($i=0;$i<$n;$i++) {
    if ($users[$i]->socket == $socket) {
      $found = $i;
      break;
    }
  }
  if (!is_null($found)) {
    array_splice($users, $found, 1);
  }
  $index = array_search($socket, $sockets);
  socket_close($socket);
  echo $socket." DISCONNECTED!\n";
  if ($index>=0) {
    array_splice($sockets, $index, 1);
  }
}

function dohandshake($user, $buffer) {
  $headers = getheaders($buffer);
  $acceptkey = base64_encode(sha1($headers[4] . "258EAFA5-E914-47DA-95CA-C5AB0DC85B11",true));
  $upgrade  = "HTTP/1.1 101 Switching Protocols\r\n" .
               "Upgrade: websocket\r\n" .
               "Connection: Upgrade\r\n" .
               "Sec-WebSocket-Accept: $acceptkey\r\n\r\n";
  socket_write($user->socket, $upgrade, strlen($upgrade));
  $user->handshake = true;
  echo "Done handshaking...\n";
}

function getheaders($req) {
  $r=$h=$u=$c=$key=$protocol=$version=$o=$data=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("/Upgrade: (.*)\r\n/", $req, $match)) {
    $u = $match[1];
  }
  if (preg_match("/Connection: (.*)\r\n/", $req, $match)) {
    $c = $match[1];
  }
  if (preg_match("/Sec-WebSocket-Key: (.*)\r\n/", $req, $match)) {
    $key = $match[1];
  }
  if (preg_match("/Sec-WebSocket-Protocol: (.*)\r\n/", $req, $match)) {
    $protocol = $match[1];
  }
  if (preg_match("/Sec-WebSocket-Version: (.*)\r\n/", $req, $match)) {
    $version = $match[1];
  }
  if (preg_match("/Origin: (.*)\r\n/", $req, $match)) {
    $o = $match[1];
  }
  if (preg_match("/\r\n(.*?)$/", $req, $match)) {
    $data = $match[1];
  }
  return array($r,$h,$u,$c,$key,$protocol,$version,$o,$data);
}

function getuserbysocket($socket) {
  global $users;
  $found = null;
  foreach ($users as $user) {
    if ($user->socket == $socket) {
      $found = $user;
      break;
    }
  }
  return $found;
}

class User {
  var $id;
  var $socket;
  var $handshake;
}

?>

Pihak Pelanggan Kod:

var connection = new WebSocket('ws://localhost:12345');

connection.onopen = function () {
  connection.send('Ping');
};

connection.onerror = function (error) {
  console.log('WebSocket Error ' + error);
};

connection.onmessage = function (e) {
  console.log('Server: ' + e.data);
};

Penyelesaian masalah:

Jika anda menemui mesej ralat "Firefox tidak dapat mewujudkan sambungan ke pelayan di ws:// localhost:12345/", semak perkara berikut:

• Pastikan kod pelayan anda berjalan pada port 12345.
• Sahkan bahawa kod sebelah pelanggan anda bersambung ke nama hos dan port yang betul.
• Pastikan kod anda melaksanakan prosedur jabat tangan WebSocket dengan betul seperti yang digariskan dalam spesifikasi RFC 6455.
• Pastikan anda mengendalikan bingkai dan bingkai WebSocket dengan betul bertopeng.

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