(PHP 8 >= 8.1.0)
Fiberler, tamamen yığıtlanabilen ve yürütmeyi kesintiye uğratılabilen işlevlerdir. Fiberin çağrı yığıtının herhangi bir yerinde askıya alınmasıyla yürütmenin bekletilmesi ve daha sonra fiberin yürütmeyi kaldığı yerden devam ettirmesi sağlanabilir.
Fiberler icra yığıtınını tamamını bekletebilir, böylece işlevin davranışını değiştirmek için işlevin doğrudan çağrılması gerekmez.
Fiber::suspend() çağrısı ile çağrı yığıtının herhangi bir yerinde yürütme kesintiye uğratılabilir (yani, Fiber::suspend() oldukça iç içe çağrıların derinlerinde yer alabileceği gibi hiçbir yerde de var olmayabilir).
Yığıtsız üreteçlerin (Generator) tersine, her Fiber sınıfının kendi çağrı yığıtı vardır. Böylece, oldukça iç içe işlev çağrılarında bile bekletme sağlanabilmektedir. Bir kesinti noktası belirten bir işlev (yani, Fiber::suspend() çağrısı), Fiber::suspend() dönüş türünün değiştirilmemesini gerektirir (bir Generator örneğinden dönen yield deyimini kullanan bir işlevin tersine).
Fiberler PHP VM içinden çağrılanlar dahil, array_map() işlevine sağlanan işlevler veya Iterator nesnesi üzerinde foreach ile çağrılan yöntemler gibi, herhangi bir işlev çağrısını askıya alabilir.
Bir kere askıya alınınca, Fiber::resume() işlevi herhangi bir değerle çağrılarak veya Fiber::throw() kullanarak fiber içinde bir istisna yavrulatarak, fiber yürütmesi kaldığı yerden devam ettirilebilir. Değer, Fiber::suspend() yönteminden veya yavrulanan istisnadan döndürülür.
Bilginize: Geçerli sınırlamalar nedeniyle, bir nesnenin yıkıcısında fiberler arasında seçim yapmak mümkün değildir.
Örnek 1 - Temel kullanım örneği
<?php
$fiber = new Fiber(function (): void {
$value = Fiber::suspend('fiber');
echo "Fiberi devam ettirmekte kullanılan değer: ", $value, PHP_EOL;
});
$value = $fiber->start();
echo "Fiber askıya alındığındaki değer: ", $value, PHP_EOL;
$fiber->resume('test');
?>
Yukarıdaki örneğin çıktısı:
Fiber askıya alınırken kullanılan değer: fiber Fiberi devam ettirmekte kullanılan değer: test
Perhaps not using the same variable name everywhere will be a good idea
<?php
$fiber = new Fiber(function (): void {
$parm = Fiber::suspend('fiber');
echo "Value used to resume fiber: ", $parm, PHP_EOL;
});
$res = $fiber->start();
echo "Value from fiber suspending: ", $res, PHP_EOL;
$fiber->resume('test');
?>
Here is a simple scheduler and thread pool that implements multithreading using fibers and tick functions in PHP 8.1 and returns the return value of each function in the pool in an array at the end.
Note that due to some bugs, you need to register a new tick function for each "thread". Remember to unregister all of them at the end.
The link bellow is the discussion on a bug that is going on right now (At the time of writing this). Note that based on the discussion, the ability to call Fiber::suspend() inside tick function may become forbidden in PHP 8.2+. But if the bug gets fixed, you can move register_tick_function() line to the top of the class, and this simple multithreading class in pure PHP code will work like a charm.
https://github.com/php/php-src/issues/8960
<?php
declare(ticks=1);
class Thread {
protected static $names = [];
protected static $fibers = [];
protected static $params = [];
public static function register(string|int $name, callable $callback, array $params)
{
self::$names[] = $name;
self::$fibers[] = new Fiber($callback);
self::$params[] = $params;
}
public static function run() {
$output = [];
while (self::$fibers) {
foreach (self::$fibers as $i => $fiber) {
try {
if (!$fiber->isStarted()) {
// Register a new tick function for scheduling this fiber
register_tick_function('Thread::scheduler');
$fiber->start(...self::$params[$i]);
} elseif ($fiber->isTerminated()) {
$output[self::$names[$i]] = $fiber->getReturn();
unset(self::$fibers[$i]);
} elseif ($fiber->isSuspended()) {
$fiber->resume();
}
} catch (Throwable $e) {
$output[self::$names[$i]] = $e;
}
}
}
return $output;
}
public static function scheduler () {
if(Fiber::getCurrent() === null) {
return;
}
// running Fiber::suspend() in this if condition will prevent an infinite loop!
if(count(self::$fibers) > 1)
{
Fiber::suspend();
}
}
}
?>
And here is an example code on how to use above Thread class:
<?php
// defining a non-blocking thread, so multiple calls will run in concurrent mode using above Thread class.
function thread (string $print, int $loop)
{
$i = $loop;
while ($i--){
echo $print;
}
return "Thread '{$print}' finished after printing '{$print}' for {$loop} times!";
}
// registering 6 Threads (A, B, C, D, E, and F)
foreach(range('A', 'F') as $c) {
Thread::register($c, 'thread', [$c, rand(5, 20)]);
}
// run threads and wait until execution finishes
$outputs = Thread::run();
// print outputs
echo PHP_EOL, '-------------- RETURN VALUES --------------', PHP_EOL;
print_r($outputs);
?>
The output will be something like this (but probably different):
ABCDEFABCDEFABCDEFABCDEFABCDEFABCEFABFABFABEBEFBEFEFEFAABEABEBEFBEFFAAAAAA
-------------- RETURN VALUES --------------
Array
(
[D] => Thread 'D' finished after printing 'D' for 5 times!
[C] => Thread 'C' finished after printing 'C' for 6 times!
[E] => Thread 'E' finished after printing 'E' for 15 times!
[B] => Thread 'B' finished after printing 'B' for 15 times!
[F] => Thread 'F' finished after printing 'F' for 15 times!
[A] => Thread 'A' finished after printing 'A' for 18 times!
)
One of examples, how to make multi_curl faster twice (pseudocode) using Fibers:
<?php
$curlHandles = [];
$urls = [
'https://example.com/1',
'https://example.com/2',
...
'https://example.com/1000',
];
$mh = curl_multi_init();
$mh_fiber = curl_multi_init();
$halfOfList = floor(count($urls) / 2);
foreach ($urls as $index => $url) {
$ch = curl_init($url);
$curlHandles[] = $ch;
// half of urls will be run in background in fiber
$index > $halfOfList ? curl_multi_add_handle($mh_fiber, $ch) : curl_multi_add_handle($mh, $ch);
}
$fiber = new Fiber(function (CurlMultiHandle $mh) {
$still_running = null;
do {
curl_multi_exec($mh, $still_running);
Fiber::suspend();
} while ($still_running);
});
// run curl multi exec in background while fiber is in suspend status
$fiber->start($mh_fiber);
$still_running = null;
do {
$status = curl_multi_exec($mh, $still_running);
} while ($still_running);
do {
/**
* at this moment curl in fiber already finished (maybe)
* so we must refresh $still_running variable with one more cycle "do while" in fiber
**/
$status_fiber = $fiber->resume();
} while (!$fiber->isTerminated());
foreach ($curlHandles as $index => $ch) {
$index > $halfOfList ? curl_multi_remove_handle($mh_fiber, $ch) : curl_multi_remove_handle($mh, $ch);
}
curl_multi_close($mh);
curl_multi_close($mh_fiber);
?>
Fiber::isRunning does not return a value
Sample
-------
<?php
$fiber = new Fiber(function (): void {
$value = Fiber::suspend('suspend');
echo "Fiber is resumed with value: ", $value, "\n";
});
echo "Fiber not yet started.", "\n";
$value = $fiber->start();
echo "Fiber is started: ", $fiber->isStarted(), "\n";
echo "Fiber is suspended: ", $fiber->isSuspended(), "\n";
echo "Fiber is running: ", $fiber->isRunning(), "\n";
echo "Fiber is suspended with value: ", $value, "\n";
$fiber->resume('resume');
echo "Fiber is running: ", $fiber->isRunning(), "\n";
?>
Output
---
Fiber not yet started. Fiber is started: 1 Fiber is suspended: 1 Fiber is running: Fiber is suspended with value: suspend Fiber is resumed with value: resume Fiber is running:
Example of the same functionality showing what is the difference between Fiber and Generator
<?php
$gener = (function () use (&$gener): Generator {
$userfunc = function () use (&$gener) : Generator {
register_shutdown_function(function () use (&$gener) {
$gener->send('test');
});
return yield 'test';
};
$parm = yield from $userfunc();
echo "Value used to resume fiber: ", $parm, PHP_EOL;
})();
$res = $gener->current();
echo "Value from fiber suspending: ", $res, PHP_EOL;
?>
<?php
$fiber = new Fiber(function () use (&$fiber) : void {
$userfunc = function () use (&$fiber) : string {
register_shutdown_function(function () use (&$fiber) {
$fiber->resume('test');
});
return Fiber::suspend('fiber');
};
$parm = $userfunc();
echo "Value used to resume fiber: ", $parm, PHP_EOL;
});
$res = $fiber->start();
echo "Value from fiber suspending: ", $res, PHP_EOL;
?>
I think that in some cases it makes sense to convert a Fiber to a Generator (Coroutine) for convenience. In such cases, this code will be useful:
<?php
function fiber_to_coroutine(\Fiber $fiber): \Generator
{
$index = -1; // Note: Pre-increment is faster than post-increment.
$value = null;
// Allow an already running fiber.
if (!$fiber->isStarted()) {
$value = yield ++$index => $fiber->start();
}
// A Fiber without suspends should return the result immediately.
if (!$fiber->isTerminated()) {
while (true) {
$value = $fiber->resume($value);
// The last call to "resume()" moves the execution of the
// Fiber to the "return" stmt.
//
// So the "yield" is not needed. Skip this step and return
// the result.
if ($fiber->isTerminated()) {
break;
}
$value = yield ++$index => $value;
}
}
return $fiber->getReturn();
}
?>
