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Swoole is an event-driven asynchronous & coroutine-based concurrency networking communication engine with high performance written in C and C++ for PHP.

✨Event-based

The network layer in Swoole is event-based and takes full advantage of the underlying epoll/kqueue implementation, making it really easy to serve millions of requests.

Swoole 4.x uses a brand new engine kernel and now it has a full-time developer team, so we are entering an unprecedented period in PHP history which offers a unique possibility for rapid evolution in performance.

⚡️Coroutine

Swoole 4.x or later supports the built-in coroutine with high availability, and you can use fully synchronized code to implement asynchronous performance. PHP code without any additional keywords, the underlying automatic coroutine-scheduling.

Developers can understand coroutines as ultra-lightweight threads, and you can easily create thousands of coroutines in a single process.

MySQL

Concurrency 10K requests to read data from MySQL takes only 0.2s!

$s = microtime(true);
Co\run(function() {
    for ($c = 100; $c--;) {
        go(function () {
            $mysql = new Swoole\Coroutine\MySQL;
            $mysql->connect([
                'host' => '127.0.0.1',
                'user' => 'root',
                'password' => 'root',
                'database' => 'test'
            ]);
            $statement = $mysql->prepare('SELECT * FROM `user`');
            for ($n = 100; $n--;) {
                $result = $statement->execute();
                assert(count($result) > 0);
            }
        });
    }
});
echo 'use ' . (microtime(true) - $s) . ' s';

Mixed server

You can create multiple services on the single event loop: TCP, HTTP, Websocket and HTTP2, and easily handle thousands of requests.

function tcp_pack(string $data): string
{
    return pack('N', strlen($data)) . $data;
}
function tcp_unpack(string $data): string
{
    return substr($data, 4, unpack('N', substr($data, 0, 4))[1]);
}
$tcp_options = [
    'open_length_check' => true,
    'package_length_type' => 'N',
    'package_length_offset' => 0,
    'package_body_offset' => 4
];

$server = new Swoole\WebSocket\Server('127.0.0.1', 9501, SWOOLE_BASE);
$server->set(['open_http2_protocol' => true]);
// http && http2
$server->on('request', function (Swoole\Http\Request $request, Swoole\Http\Response $response) {
    $response->end('Hello ' . $request->rawcontent());
});
// websocket
$server->on('message', function (Swoole\WebSocket\Server $server, Swoole\WebSocket\Frame $frame) {
    $server->push($frame->fd, 'Hello ' . $frame->data);
});
// tcp
$tcp_server = $server->listen('127.0.0.1', 9502, SWOOLE_TCP);
$tcp_server->set($tcp_options);
$tcp_server->on('receive', function (Swoole\Server $server, int $fd, int $reactor_id, string $data) {
    $server->send($fd, tcp_pack('Hello ' . tcp_unpack($data)));
});
$server->start();

Coroutine clients

Whether you DNS query or send requests or receive responses, all of these are scheduled by coroutine automatically.

go(function () {
    // http
    $http_client = new Swoole\Coroutine\Http\Client('127.0.0.1', 9501);
    assert($http_client->post('/', 'Swoole Http'));
    var_dump($http_client->body);
    // websocket
    $http_client->upgrade('/');
    $http_client->push('Swoole Websocket');
    var_dump($http_client->recv()->data);
});
go(function () {
    // http2
    $http2_client = new Swoole\Coroutine\Http2\Client('localhost', 9501);
    $http2_client->connect();
    $http2_request = new Swoole\Http2\Request;
    $http2_request->method = 'POST';
    $http2_request->data = 'Swoole Http2';
    $http2_client->send($http2_request);
    $http2_response = $http2_client->recv();
    var_dump($http2_response->data);
});
go(function () use ($tcp_options) {
    // tcp
    $tcp_client = new Swoole\Coroutine\Client(SWOOLE_TCP);
    $tcp_client->set($tcp_options);
    $tcp_client->connect('127.0.0.1', 9502);
    $tcp_client->send(tcp_pack('Swoole Tcp'));
    var_dump(tcp_unpack($tcp_client->recv()));
});

Channel

Channel is the only way for exchanging data between coroutines, the development combination of the Coroutine + Channel is the famous CSP programming model.

In Swoole development, Channel is usually used for implementing connection pool or scheduling coroutine concurrent.

The simplest example of a connection pool

In the following example, we have a thousand concurrently requests to redis. Normally, this has exceeded the maximum number of Redis connections setting and will throw a connection exception, but the connection pool based on Channel can perfectly schedule requests. We don't have to worry about connection overload.

class RedisPool
{
    /**@var \Swoole\Coroutine\Channel */
    protected $pool;

    /**
     * RedisPool constructor.
     * @param int $size max connections
     */
    public function __construct(int $size = 100)
    {
        $this->pool = new \Swoole\Coroutine\Channel($size);
        for ($i = 0; $i < $size; $i++) {
            $redis = new \Swoole\Coroutine\Redis();
            $res = $redis->connect('127.0.0.1', 6379);
            if ($res == false) {
                throw new \RuntimeException("failed to connect redis server.");
            } else {
                $this->put($redis);
            }
        }
    }

    public function get(): \Swoole\Coroutine\Redis
    {
        return $this->pool->pop();
    }

    public function put(\Swoole\Coroutine\Redis $redis)
    {
        $this->pool->push($redis);
    }

    public function close(): void
    {
        $this->pool->close();
        $this->pool = null;
    }
}

go(function () {
    $pool = new RedisPool();
    // max concurrency num is more than max connections
    // but it's no problem, channel will help you with scheduling
    for ($c = 0; $c < 1000; $c++) {
        go(function () use ($pool, $c) {
            for ($n = 0; $n < 100; $n++) {
                $redis = $pool->get();
                assert($redis->set("awesome-{$c}-{$n}", 'swoole'));
                assert($redis->get("awesome-{$c}-{$n}") === 'swoole');
                assert($redis->delete("awesome-{$c}-{$n}"));
                $pool->put($redis);
            }
        });
    }
});

Producer and consumers

Some Swoole's clients implement the defer mode for concurrency, but you can still implement it flexible with a combination of coroutines and channels.

go(function () {
    // User: I need you to bring me some information back.
    // Channel: OK! I will be responsible for scheduling.
    $channel = new Swoole\Coroutine\Channel;
    go(function () use ($channel) {
        // Coroutine A: Ok! I will show you the github addr info
        $addr_info = Co::getaddrinfo('github.com');
        $channel->push(['A', json_encode($addr_info, JSON_PRETTY_PRINT)]);
    });
    go(function () use ($channel) {
        // Coroutine B: Ok! I will show you what your code look like
        $mirror = Co::readFile(__FILE__);
        $channel->push(['B', $mirror]);
    });
    go(function () use ($channel) {
        // Coroutine C: Ok! I will show you the date
        $channel->push(['C', date(DATE_W3C)]);
    });
    for ($i = 3; $i--;) {
        list($id, $data) = $channel->pop();
        echo "From {$id}:\n {$data}\n";
    }
    // User: Amazing, I got every information at earliest time!
});

Timer

$id = Swoole\Timer::tick(100, function () {
    echo "⚙️ Do something...\n";
});
Swoole\Timer::after(500, function () use ($id) {
    Swoole\Timer::clear($id);
    echo "⏰ Done\n";
});
Swoole\Timer::after(1000, function () use ($id) {
    if (!Swoole\Timer::exists($id)) {
        echo "✅ All right!\n";
    }
});

The way of coroutine

go(function () {
    $i = 0;
    while (true) {
        Co::sleep(0.1);
        echo "📝 Do something...\n";
        if (++$i === 5) {
            echo "🛎 Done\n";
            break;
        }
    }
    echo "🎉 All right!\n";
});

🔥 Amazing runtime hooks

As of Swoole v4.1.0, we added the ability to transform synchronous PHP network libraries into co-routine libraries using a single line of code.

Simply call the Swoole\Runtime::enableCoroutine() method at the top of your script. In the sample below we connect to php-redis and concurrently read 10k requests in 0.1s:

Swoole\Runtime::enableCoroutine();
$s = microtime(true);
Co\run(function() {
    for ($c = 100; $c--;) {
        go(function () {
            ($redis = new Redis)->connect('127.0.0.1', 6379);
            for ($n = 100; $n--;) {
                assert($redis->get('awesome') === 'swoole');
            }
        });
    }
});
echo 'use ' . (microtime(true) - $s) . ' s';

By calling this method, the Swoole kernel replaces ZendVM stream function pointers. If you use php_stream based extensions, all socket operations can be dynamically converted to be asynchronous IO scheduled by coroutine at runtime!

How many things you can do in 1s?

Sleep 10K times, read, write, check and delete files 10K times, use PDO and MySQLi to communicate with the database 10K times, create a TCP server and multiple clients to communicate with each other 10K times, create a UDP server and multiple clients to communicate with each other 10K times... Everything works well in one process!

Just see what the Swoole brings, just imagine...

Swoole\Runtime::enableCoroutine();
$s = microtime(true);
Co\run(function() {
    // i just want to sleep...
    for ($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';

⌛️ Installation

As with any open source project, Swoole always provides the most reliable stability and the most powerful features in the latest released version. Please ensure as much as possible that you are using the latest version.

Compiling requirements

• Linux, OS X or Cygwin, WSL
• PHP 7.0.0 or later (The higher the version, the better the performance.)
• GCC 4.8 or later

1. Install via PECL (beginners)

pecl install swoole

2. Install from source (recommended)

Please download the source packages from Releases or:

git clone https://github.com/swoole/swoole-src.git && \
cd swoole-src && \
git checkout v4.x.x

Compile and install at the source folder:

phpize && \
./configure && \
make && make install

Enable extension in PHP

After compiling and installing to the system successfully, you have to add a new line extension=swoole.so to php.ini to enable Swoole extension.

Extra compiler configurations

for example: ./configure --enable-openssl --enable-sockets

• --enable-openssl or --with-openssl-dir=DIR
• --enable-sockets
• --enable-http2
• --enable-mysqlnd (need mysqlnd, it just for supporting $mysql->escape method)

Upgrade

⚠️ If you upgrade from source, don't forget to make clean before you upgrade your swoole

1. pecl upgrade swoole
2. git pull && cd swoole-src && make clean && make && sudo make install
3. if you change your PHP version, please re-run phpize clean && phpize then try to compile

Major change since version 4.3.0

Async clients and API are moved to a separate PHP extension swoole_async since version 4.3.0, install swoole_async:

git clone https://github.com/swoole/async-ext.git
cd async-src
phpize
./configure
make -j 4
sudo make install

Enable it by adding a new line extension=swoole_async.so to php.ini.

💎 Frameworks & Components

• Hyperf is a coroutine framework that focuses on hyperspeed and flexibility, specifically used for build microservices or middlewares.
• Swoft is a modern, high-performance AOP and coroutine PHP framework.
• Easyswoole is a simple, high-performance PHP framework, based on Swoole, which makes using Swoole as easy as echo "hello world".
• MixPHP is a powerful single-threaded coroutine framework with a very small footprint, simple and elegant.
• imi is a high-performance coroutine application development framework based on PHP Swoole, which supports the development of HttpApi, WebSocket, TCP, UDP services.
• Saber is a human-friendly, high-performance HTTP client component that has almost everything you can imagine.

🛠 Develop & Discussion

• 中文文档: https://wiki.swoole.com
• Documentation: https://www.swoole.co.uk/docs
• IDE Helper & API: https://github.com/swoole/ide-helper
• 中文社区: https://wiki.swoole.com/#/other/discussion
• Twitter: https://twitter.com/php_swoole
• Slack Group: https://swoole.slack.com

🍭 Benchmark

• On the open source Techempower Web Framework benchmarks Swoole used MySQL database benchmark to rank first, and all performance tests ranked in the first echelon.
• You can just run Benchmark Script to quickly test the maximum QPS of Swoole-HTTP-Server on your machine.

🔰️ Security issues

Security issues should be reported privately, via email, to the Swoole develop team [email protected]. You should receive a response within 24 hours. If for some reason you do not, please follow up via email to ensure we received your original message.

🖊️ Contribution

Your contribution to Swoole development is very welcome!

You may contribute in the following ways:

• Report issues and feedback
• Submit fixes, features via Pull Request
• Write/polish documentation

❤️ Contributors

This project exists thanks to all the people who contribute. [Contributors].

🎙️ Official Evangelist

Demin has been playing with PHP since 2000, focusing on building high-performance, secure web services. He is an occasional conference speaker on PHP and Swoole, and has been working for companies in the states like eBay, Visa and Glu Mobile for years. You may find Demin on Twitter or GitHub.

📃 License

Apache License Version 2.0 see http://www.apache.org/licenses/LICENSE-2.0.html