韩天峰(Rango)的博客

客户端socket连接到ProxyServer后，创建一个socket连接到后端Server。并监听后端Server的回包。 客户端向ProxyServer发送请求包，proxy服务器会透明地将此包发往后端Server。
当后端Server返回包时，找到对应的客户端socket，向此socket发送回应的数据包。
此程序将swoole扩展提供的Server和Client结合在一起使用， ProxyServer对客户端连接来说是服务器端，但对backend服务器来说是客户端。
所有网络IO都是基于epoll事件循环，全异步非阻塞的。性能非常高。 长连接可以达到 10万qps的处理能力。

这里对后端Server和客户端之间使用了1对1的模式，可以改进为n对1连接池的模式，节约backend Server的TCP连接数量。当onReceve收到客户端请求时，将客户端连接与backend连接绑定。返回响应数据后解除绑定，使连接可供下一个客户端使用。

 
<?php
class ProxyServer
{
    protected $clients;
    protected $backends;
    protected $serv;

    function run()
    {
        $serv = swoole_server_create("127.0.0.1", 9509);
        swoole_server_set($serv, array(
            'timeout' => 1, //select and epoll_wait timeout.
            'poll_thread_num' => 1, //reactor thread num
            'worker_num' => 1, //reactor thread num
            'backlog' => 128, //listen backlog
            'max_conn' => 10000,
            'dispatch_mode' => 2,
            //'open_tcp_keepalive' => 1,
            'log_file' => '/tmp/swoole.log', //swoole error log
        ));
        swoole_server_handler($serv, 'onWorkerStart', array($this, 'onStart'));
        swoole_server_handler($serv, 'onConnect', array($this, 'onConnect'));
        swoole_server_handler($serv, 'onReceive', array($this, 'onReceive'));
        swoole_server_handler($serv, 'onClose', array($this, 'onClose'));
        swoole_server_handler($serv, 'onWorkerStop', array($this, 'onShutdown'));
        //swoole_server_addtimer($serv, 2);
        #swoole_server_addtimer($serv, 10);
        swoole_server_start($serv);
    }

    function onStart($serv)
    {
        $this->serv = $serv;
        echo "Server: start.Swoole version is [" . SWOOLE_VERSION . "]\n";
    }

    function onShutdown($serv)
    {
        echo "Server: onShutdown\n";
    }

    function onClose($serv, $fd, $from_id)
    {
        //backend
        if (isset($this->clients[$fd])) {
            $backend_client = $this->clients[$fd]['socket'];
            unset($this->clients[$fd]);
            $backend_client->close();
            unset($this->backends[$backend_client->sock]);
            echo "client close\n";
        }
    }

    function onConnect($serv, $fd, $from_id)
    {
        $socket = new swoole_client(SWOOLE_SOCK_TCP, SWOOLE_SOCK_ASYNC);
        echo microtime() . ": Client[$fd] backend-sock[{$socket->sock}]: Connect.\n";
        $this->backends[$socket->sock] = array(
            'client_fd' => $fd,
            'socket' => $socket,
        );
        $this->clients[$fd] = array(
            'socket' => $socket,
        );
        $socket->on('connect', function ($socket) {
            echo "connect to backend server success\n";
        });
        $socket->on('error', function ($socket) {
            echo "connect to backend server fail\n";
        });
        $socket->on('receive', function ($socket) {
            swoole_server_send($this->serv, $this->backends[$socket->sock]['client_fd'], $socket->recv());
        });
        $socket->connect('127.0.0.1', 9501, 0.2);
    }

    function onReceive($serv, $fd, $from_id, $data)
    {
        echo microtime() . ": client receive\n";
        $backend_socket = $this->clients[$fd]['socket'];
        $backend_socket->send($data);
        echo microtime() . ": send to backend\n";
        echo str_repeat('-', 100) . "\n";
    }
}

$serv = new ProxyServer();
$serv->run();