Concurrent Socket Pattern 协程安全的单连接模式

[Reasno]

一般来说Swoole下一个socket只能在一个协程写，一个协程读。

当然大多数情况下直接使用连接池就可以了，不用太关心这个限制。

但是，在需要保持事务、http2等特殊情况下，是必须使用一个连接的。

通过一层封装我们可以使单一连接变得协程安全。

<?php

class ConcurrentSocketPattern
{
    protected Swoole\Coroutine\Channel $chan;

    protected Swoole\Coroutine\Socket $socket;

    public function __construct()
    {
        $this->chan = new Swoole\Coroutine\Channel();
        $this->socket = new Swoole\Coroutine\Socket(AF_INET, SOCK_STREAM, 0);
    }

    public function loop()
    {
        while (true) {
            $closure = $this->chan->pop();
            if (! $closure) {
                break;
            }
            $closure->call($this);
        }
    }

    public function send($str)
    {
        $cont = new Swoole\Coroutine\Channel();
        $this->chan->push(function () use ($cont, $str) {
            $this->socket->send($str);
            $cont->push(true);
        });
        $cont->pop();
    }

    public function recv()
    {
        $cont = new Swoole\Coroutine\Channel();
        $this->chan->push(function () use ($cont) {
            $str = $this->socket->recv();
            $cont->push($str);
        });
        return $cont->pop();
    }

    public function connect()
    {
        $cont = new Swoole\Coroutine\Channel();
        $this->chan->push(function () use ($cont) {
            $this->socket->connect('localhost', 2701);
            $cont->push(true);
        });
        $cont->pop();
    }
}

Swoole\Coroutine\Run(function () {
    $c = new ConcurrentSocketPattern();
    go(fn() => $c->loop());
    go(fn() => $c->connect());
    go(fn() => $c->send('hello'));
    go(fn() => $c->recv());
    sleep(3);
});

示例中隐去了错误处理。