Coroutines

OpenSwoole coroutines are cooperative — they yield only on I/O, making parallel fetch trivial. ZealPHP enables HOOK_ALL so all PHP I/O (file, curl, PDO) becomes coroutine-aware automatically.

GET Parallel fetch — 3 coroutines in 1s not 3s

$app->route('/demo/coroutine/parallel', function() {
    $ch    = new Channel(3);
    $start = microtime(true);

    go(fn() => [$ch->push(simulated_fetch('users',  1))]);
    go(fn() => [$ch->push(simulated_fetch('orders', 1))]);
    go(fn() => [$ch->push(simulated_fetch('stats',  1))]);

    $results = [];
    for ($i = 0; $i < 3; $i++) $results[] = $ch->pop();

    return ['results' => $results, 'elapsed_s' => round(microtime(true) - $start, 3)];
    // All 3 run in parallel → ~1s total, not 3s
});

LIVE OUTPUT Click Run →

GET Channel — producer/consumer pattern

$app->route('/demo/coroutine/channel', function() {
    $ch = new Channel(1); // buffer of 1

    go(function() use ($ch) {
        co::sleep(1);
        $ch->push(['value' => 42, 'from' => 'producer coroutine']);
    });

    $result = $ch->pop(); // blocks until producer pushes
    return ['received' => $result, 'pattern' => 'producer/consumer'];
});

LIVE OUTPUT Click Run →

How it works

Primitive	Purpose
`go(callable)`	Spawn a coroutine. Runs concurrently when current coroutine yields.
`co::sleep(float $s)`	Yield for N seconds without blocking the event loop.
`new Channel(int $capacity)`	Buffered queue for coroutine communication. `push()` + `pop()`.
`usleep(int $us)`	Coroutine-aware micro-sleep under HOOK_ALL (use for sub-second delays).
`OpenSwoole\Runtime::HOOK_ALL`	Makes all PHP I/O — curl, file, PDO, sleep — yield the event loop.

App::superglobals(false) must be called before App::init() to enable coroutine mode. In coroutine mode, every request runs in its own coroutine with isolated G::instance() state.