Returning a value from asynchronous PHP - php

Question

I would like to return a value from an asynchronous function in PHP ... I use icicle.io here, but I'm happy to use whatever, provided it does what I want to do! Anyway, this is some code below
<?php
require __DIR__ . '/vendor/autoload.php';
use Icicle\Coroutine\Coroutine;
use Icicle\Loop;
function getArray($int) {
yield array ($int, $int + 1, $int + 2);
}
function getArrays() {
$numbers = array (1, 4, 7);
$results = array();
foreach ($numbers as $number) {
array_push($results, (yield(getArray($number))));
}
yield call_user_func_array('array_merge', $results);
}
$coroutine = new Coroutine(getArrays());
$data = $coroutine->then(
function ($result) {
$data = print_r($result, true);
return "Result: {$data}\n";
},
function (Exception $e) {
echo "Error: {$e->getMessage()}\n";
}
)->done(function ($value) {
echo $value;
});
Loop\run();
What I'd really like to do is to put that last little bit in a function, so it looks more like this:
function sync() {
$coroutine = new Coroutine(getArrays());
$data = $coroutine->then(
function ($result) {
$data = print_r($result, true);
return "Result: {$data}\n";
},
function (Exception $e) {
echo "Error: {$e->getMessage()}\n";
}
)->done(function ($value) {
return $value;
});
Loop\run();
return /* the value */;
}
Then from my cool software, I can call sync() as if it's a synchronous function, blissfully unaware of the asynchronous shenanigans going on behind the scenes.
Has anyone done this, or have some suggestions as to how I might? At the moment the best I've come up with is (ab)using the output buffer & serialize()/unserialize() functions, but since I'm doing it all out of some desire to improve the performance, that seems rather backwards!!

Answer 1

You can synchronously wait for the resolution of an Awaitable (including a Coroutine) by using the wait() method. This method ticks the event loop until the coroutine is resolved. This means your sync() function can simply call this method on the coroutine object and return the result.
function sync() {
$coroutine = new Coroutine(getArrays());
return $coroutine->wait();
}