协程初探

!>建议先看此节，了解协程基本概念再看本文。

Swoole4使用全新的协程内核引擎，现在我们拥有一个全职的开发团队，因此我们正在进入PHP历史上前所未有的时期，为性能的高速提升提供了独一无二的可能性。

Swoole4或更高版本拥有高可用性的内置协程，您可以使用完全同步的代码来实现异步IO，PHP代码没有任何额外的关键字，底层会自动进行协程调度。

使用协程你可以在一秒钟里做多少事?

睡眠1万次，读取，写入，检查和删除文件1万次，使用PDO和MySQLi与数据库通信1万次，创建TCP服务器和多个客户端相互通信1万次，创建UDP服务器和多个客户端到相互通信1万次......一切都在一个进程中完美完成！

//go关键词创建一个协程，可以简单的理解为创建了一个线程

Swoole\Runtime::enableCoroutine();//此行代码后，文件操作，sleep，Mysqli，PDO，streams等都变成异步IO，见'一键协程化'章节
$s = microtime(true);
//Co/run()见'协程容器'章节
Co\run(function() {
    // i just want to sleep...
    for ($c = 100; $c--;) {
        go(function () {
            for ($n = 100; $n--;) {
                usleep(1000);
            }
        });
    }

    // 10k file read and write
    for ($c = 100; $c--;) {
        go(function () use ($c) {
            $tmp_filename = "/tmp/test-{$c}.php";
            for ($n = 100; $n--;) {
                $self = file_get_contents(__FILE__);
                file_put_contents($tmp_filename, $self);
                assert(file_get_contents($tmp_filename) === $self);
            }
            unlink($tmp_filename);
        });
    }

    // 10k pdo and mysqli read
    for ($c = 50; $c--;) {
        go(function () {
            $pdo = new PDO('mysql:host=127.0.0.1;dbname=test;charset=utf8', 'root', 'root');
            $statement = $pdo->prepare('SELECT * FROM `user`');
            for ($n = 100; $n--;) {
                $statement->execute();
                assert(count($statement->fetchAll()) > 0);
            }
        });
    }
    for ($c = 50; $c--;) {
        go(function () {
            $mysqli = new Mysqli('127.0.0.1', 'root', 'root', 'test');
            $statement = $mysqli->prepare('SELECT `id` FROM `user`');
            for ($n = 100; $n--;) {
                $statement->bind_result($id);
                $statement->execute();
                $statement->fetch();
                assert($id > 0);
            }
        });
    }

    // php_stream tcp server & client with 12.8k requests in single process
    function tcp_pack(string $data): string
    {
        return pack('n', strlen($data)) . $data;
    }

    function tcp_length(string $head): int
    {
        return unpack('n', $head)[1];
    }

    go(function () {
        $ctx = stream_context_create(['socket' => ['so_reuseaddr' => true, 'backlog' => 128]]);
        $socket = stream_socket_server(
            'tcp://0.0.0.0:9502',
            $errno, $errstr, STREAM_SERVER_BIND | STREAM_SERVER_LISTEN, $ctx
        );
        if (!$socket) {
            echo "$errstr ($errno)\n";
        } else {
            $i = 0;
            while ($conn = stream_socket_accept($socket, 1)) {
                stream_set_timeout($conn, 5);
                for ($n = 100; $n--;) {
                    $data = fread($conn, tcp_length(fread($conn, 2)));
                    assert($data === "Hello Swoole Server #{$n}!");
                    fwrite($conn, tcp_pack("Hello Swoole Client #{$n}!"));
                }
                if (++$i === 128) {
                    fclose($socket);
                    break;
                }
            }
        }
    });
    for ($c = 128; $c--;) {
        go(function () {
            $fp = stream_socket_client("tcp://127.0.0.1:9502", $errno, $errstr, 1);
            if (!$fp) {
                echo "$errstr ($errno)\n";
            } else {
                stream_set_timeout($fp, 5);
                for ($n = 100; $n--;) {
                    fwrite($fp, tcp_pack("Hello Swoole Server #{$n}!"));
                    $data = fread($fp, tcp_length(fread($fp, 2)));
                    assert($data === "Hello Swoole Client #{$n}!");
                }
                fclose($fp);
            }
        });
    }

    // udp server & client with 12.8k requests in single process
    go(function () {
        $socket = new Swoole\Coroutine\Socket(AF_INET, SOCK_DGRAM, 0);
        $socket->bind('127.0.0.1', 9503);
        $client_map = [];
        for ($c = 128; $c--;) {
            for ($n = 0; $n < 100; $n++) {
                $recv = $socket->recvfrom($peer);
                $client_uid = "{$peer['address']}:{$peer['port']}";
                $id = $client_map[$client_uid] = ($client_map[$client_uid] ?? -1) + 1;
                assert($recv === "Client: Hello #{$id}!");
                $socket->sendto($peer['address'], $peer['port'], "Server: Hello #{$id}!");
            }
        }
        $socket->close();
    });
    for ($c = 128; $c--;) {
        go(function () {
            $fp = stream_socket_client("udp://127.0.0.1:9503", $errno, $errstr, 1);
            if (!$fp) {
                echo "$errstr ($errno)\n";
            } else {
                for ($n = 0; $n < 100; $n++) {
                    fwrite($fp, "Client: Hello #{$n}!");
                    $recv = fread($fp, 1024);
                    list($address, $port) = explode(':', (stream_socket_get_name($fp, true)));
                    assert($address === '127.0.0.1' && (int)$port === 9503);
                    assert($recv === "Server: Hello #{$n}!");
                }
                fclose($fp);
            }
        });
    }
});
echo 'use ' . (microtime(true) - $s) . ' s';