Async event loop

PHP is a procedural language — it won’t call your Deferred's processing function automatically. For your promises to resolve, you’ll need an event loop to run the pending processes.

This could be a simple loop like:

while($runner->hasPendingTasks()) {
	$runner->tick();
}

For production use, consider using a solution built for looping PHP. PHP.GT/async is the complementary library for handling asynchronous looping, which is built to coordinate these tasks efficiently in real-world PHP environments.

To set up an example loop using PHP.GT/async, create a new Timer...

use Gt\Async\PeriodicTimer;

$timer = new PeriodicTimer(0.1, true);
$timer->addCallback(function() {
	echo ".";
});

...attach the Timer and your Deferred to the Loop...

use Gt\Async\Loop;

$loop = new Loop();
$loop->addTimer($timer);

/** @var Gt\Promise\Deferred $deferred This is the Deferred object you created. **/

$loop->addDeferredToTimer($deferred);

...and once everything is completed, you can run the loop, and everything will run asynchronously as the timer ticks:

$loop->run();

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For a complex real-world codebase that heavily uses Async and Promises, please see PHP.GT/Fetch, a non-blocking HTTP client that replicates the web standard Fetch protocol in PHP.