Detailed introduction to code cases for writing TCP server and client programs in PHP

<?php    
//确保在连接客户端时不会超时    
set_time_limit(0);    
//设置IP和端口号    
$address = "127.0.0.1";    
$port = 3046;   
/**  
 * 创建一个SOCKET   
 * AF_INET=是ipv4 如果用ipv6，则参数为 AF_INET6  
 * SOCK_STREAM为socket的tcp类型，如果是UDP则使用SOCK_DGRAM  
*/    
$sock = socket_create(AF_INET, SOCK_STREAM, SOL_TCP) or die("socket_create() fail:" . socket_strerror(socket_last_error()) . "/n");    
//阻塞模式    
socket_set_block($sock) or die("socket_set_block() fail:" . socket_strerror(socket_last_error()) . "/n");    
//绑定到socket端口    
$result = socket_bind($sock, $address, $port) or die("socket_bind() fail:" . socket_strerror(socket_last_error()) . "/n");    
//开始监听    
$result = socket_listen($sock, 4) or die("socket_listen() fail:" . socket_strerror(socket_last_error()) . "/n");    
echo "OK\nBinding the socket on $address:$port ... ";    
echo "OK\nNow ready to accept connections.\nListening on the socket ... \n";    
do { // never stop the daemon    
    //它接收连接请求并调用一个子连接Socket来处理客户端和服务器间的信息    
    $msgsock = socket_accept($sock) or  die("socket_accept() failed: reason: " . socket_strerror(socket_last_error()) . "/n");    
    while(1){  
        //读取客户端数据    
        echo "Read client data \n";    
        //socket_read函数会一直读取客户端数据,直到遇见\n,\t或者\0字符.PHP脚本把这写字符看做是输入的结束符.    
        $buf = socket_read($msgsock, 8192);    
        echo "Received msg: $buf   \n";  
  
        if($buf == "bye"){  
            //接收到结束消息，关闭连接，等待下一个连接  
            socket_close($msgsock);  
            continue;  
        }  
            
        //数据传送 向客户端写入返回结果    
        $msg = "welcome \n";    
        socket_write($msgsock, $msg, strlen($msg)) or die("socket_write() failed: reason: " . socket_strerror(socket_last_error()) ."/n");            
    }    
        
} while (true);    
socket_close($sock);    
?>

<?php  
set_time_limit(0);  
  
$host = "127.0.0.1";  
$port = 3046;  
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP)or die("Could not create  socket\n");  
   
$connection = socket_connect($socket, $host, $port) or die("Could not connet server\n"); 
socket_write($socket, "hello socket") or die("Write failed\n");
while ($buff = socket_read($socket, 1024, PHP_NORMAL_READ)) {  
    echo("Response was:" . $buff . "\n");
	echo("input what you want to say to the server:\n");
	$text = fgets(STDIN);
	socket_write($socket, $text);
}  
socket_close($socket);
?>