PHP의 소켓 통신 메커니즘 예제에 대한 자세한 설명

<?php  
// 建立server端socket  
$tcp = getprotobyname("tcp");  
$socket = socket_create(af_inet, sock_stream, $tcp);  
socket_bind($socket, &#39;127.0.0.1&#39;, 10008);       //绑定要监听的端口  
socket_listen($socket);       //监听端口 
 
//初始化一个数据，和客户端通信  
$buffer = "connect";  
while (true) {  
    // 接受一个socket连接  
    $connection = socket_accept($socket);  
    if(!$connection){  
        echo "connect fail";  
    }else{  
            echo  "socket connected ";  
            // 向客户端传递一个信息数据  
            if ($buffer != "") {  
                echo "send data to client ";  
                socket_write($connection, $buffer . " ");  
                echo  "wrote to socket ";  
            } else {  
                echo  "no data in the buffer " ;  
            }  
            // 从客户端取得信息  
            while ($data = @socket_read($connection, 1024, php_normal_read)) {  
                    printf("buffer: " . $data . " ");  
                    //取得信息给客户端一个反馈  
                    socket_write($connection, "information received ");  
            }
    } 
 
    socket_close($connection);  
    //关闭 socket  
    printf("closed the socket ");  
}  
?>

<?php  
// 建立客户端的socet连接  
$socket = socket_create(af_inet, sock_stream, sol_tcp);  
$connection = socket_connect($socket, &#39;127.0.0.1&#39;, 10008);    //连接服务器端socket 
 
while ($buffer = @socket_read($socket, 1024, php_normal_read)) {  
    //服务端告诉客户端，自己的状态  
    if (preg_match("/not connect/",$buffer)) {  
        echo "don`t connect ";  
        break;  
    } else {  
        //服务器传来信息  
        echo "buffer data: " . $buffer . " "; 
 
        echo "writing to socket ";  
        // 将客户的信息写到通道中，传给服务器端  
        if (!socket_write($socket, "some data ")) {  
            echo "write failed ";  
        }  
        //服务器端收到信息后，给于的回应信息  
        while ($buffer = socket_read($socket, 1024, php_normal_read)) {  
                echo "sent to server: some data response from server was:" . $buffer . " ";  
        } 
 
    }  
} 
?>