PHP의 소켓-서버 통신 예제에 대한 자세한 설명

<?php 
error_reporting(E_ALL); 
set_time_limit(0); 
ob_implicit_flush(); 
//本地IP 
$address = &#39;localhost&#39;; 
//设置用111端口进行通信 
$port = 111; 
//创建SOCKET 
if (($sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)) < 0) { 
    echo "socket创建失败原因 " . socket_strerror($sock) . "\n"; 
} 
 
if (($ret = socket_bind($sock, $address, $port)) < 0) { 
    echo "创建套接字失败原因 " . socket_strerror($ret) . "\n"; 
} 
//监听 
if (($ret = socket_listen($sock, 5)) < 0) { 
    echo "监听失败原因 " . socket_strerror($ret) . "\n"; 
} 
do { 
  //接收命令  
  if (($msgsock = @socket_accept($sock)) < 0) { 
    echo "命令接收失败原因: " . socket_strerror($msgsock) . "\n"; 
    break; 
  } 
  $msg = "\nPHP Test Server. \n" ."用quit,shutdown,sun...等命令测试.\n"; 
 
  @socket_write($msgsock, $msg, strlen($msg)); 
 
  do { 
    if (false === ($buf = @socket_read($msgsock, 2048, PHP_NORMAL_READ))) { 
        echo "socket_read() failed: reason: " . socket_strerror($ret) . "\n"; 
        break 2; 
    } 
    if (!$buf = trim($buf)) { 
        continue; 
    } 
    if ($buf == &#39;quit&#39;) { 
        break; 
    } 
    if ($buf == &#39;shutdown&#39;) { 
        socket_close($msgsock); 
        break 2; 
    } 
    if ($buf == &#39;sun&#39;) { 
        echo&#39;what are you doing?&#39;; 
    } 
    $talkback = "Backinformation : &#39;$buf&#39;.\n"; 
    socket_write($msgsock, $talkback, strlen($talkback)); 
    echo "$buf\n"; 
  } while (true); 
 
  socket_close($msgsock); 
 
} while (true); 
 
socket_close($sock); 
?>

<?php 
error_reporting(E_ALL); 
//端口111 
$service_port = 111; 
//本地 
$address = &#39;localhost&#39;; 
//创建 TCP/IP socket 
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP); 
if ($socket < 0) { 
    echo "socket创建失败原因: " . socket_strerror($socket) . "\n"; 
} else { 
    echo "OK，HE HE.\n"; 
} 
$result = socket_connect($socket, $address, $service_port); 
if ($result < 0) { 
    echo "SOCKET连接失败原因: ($result) " . socket_strerror($result) . "\n"; 
} else { 
    echo "OK.\n"; 
} 
//发送命令 
$in = "HEAD / HTTP/1.1\r\n"; 
$in .= "Connection: Close\r\n\r\n"; 
$out = &#39;&#39;; 
echo "Send Command.........."; 
$in = "sun\n"; 
socket_write($socket, $in, strlen($in)); 
echo "OK.\n"; 
echo "Reading Backinformatin:\n\n"; 
while ($out = socket_read($socket, 2048)) { 
    echo $out; 
} 
echo "Close socket........"; 
socket_close($socket); 
echo "OK,He He.\n\n"; 
?>