本文实例讲述了php基于协程实现异步的方法。分享给大家供大家参考，具体如下：
github上php的协程大部分是根据这篇文章实现的：http://nikic.github.io/2012/12/22/Cooperative-multitasking-using-coroutines-in-PHP.html。
它们最终的结果都是把回调变成了优雅的顺序执行的代码，但还是阻塞的，不是真正的异步。
比如最热门的：https://github.com/recoilphp/recoil
先安装：
composer require recoil/recoil
执行：
<?php//recoil.phpinclude __DIR__ . '/vendor/autoload.php';use Recoil/React/ReactKernel;$i = 100000;ReactKernel::start(task1());ReactKernel::start(task2());function task1(){ global $i; echo "wait start" . PHP_EOL; while ($i-- > 0) { yield; } echo "wait end" . PHP_EOL;};function task2(){ echo "Hello " . PHP_EOL; yield; echo "world!" . PHP_EOL;} 结果：
wait start
//等待若干秒
wait end
Hello
world!
我本来是想让两个任务并行，结果两个任务变成了串行，中间等待的时间什么事情都干不了。React响应式的编程是严格禁止这种等待的，所以我就参照unity3d的协程自己写了个php版本的。上代码：
<?php//Coroutine.php//依赖swoole实现的定时器，也可以用其它方法实现定时器class Coroutine{ //可以根据需要更改定时器间隔，单位ms const TICK_INTERVAL = 1; private $routineList; private $tickId = -1; public function __construct() { $this->routineList = []; } public function start(Generator $routine) { $task = new Task($routine); $this->routineList[] = $task; $this->startTick(); } public function stop(Generator $routine) { foreach ($this->routineList as $k => $task) { if($task->getRoutine() == $routine){ unset($this->routineList[$k]); } } } private function startTick() { swoole_timer_tick(self::TICK_INTERVAL, function($timerId){ $this->tickId = $timerId; $this->run(); }); } private function stopTick() { if($this->tickId >= 0) { swoole_timer_clear($this->tickId); } } private function run() { if(empty($this->routineList)){ $this->stopTick(); return; } foreach ($this->routineList as $k => $task) { $task->run(); if($task->isFinished()){ unset($this->routineList[$k]); } } } }class Task{ protected $stack; protected $routine; public function __construct(Generator $routine) { $this->routine = $routine; $this->stack = new SplStack(); } /** * [run 协程调度] * @return [type] [description] */ public function run() { $routine = &$this->routine; try { if(!$routine){ return; } $value = $routine->current(); //嵌套的协程 if ($value instanceof Generator) { $this->stack->push($routine); $routine = $value; return; } //嵌套的协程返回 if(!$routine->valid() && !$this->stack->isEmpty()) { $routine = $this->stack->pop(); } $routine->next(); } catch (Exception $e) { if ($this->stack->isEmpty()) { /* throw the exception */ return; } } } /** * [isFinished 判断该task是否完成] * @return boolean [description] */ public function isFinished() { return $this->stack->isEmpty() && !$this->routine->valid(); } public function getRoutine() { return $this->routine; }} 测试代码：
<?php//test.php require 'Coroutine.php';$i = 10000;$c = new Coroutine();$c->start(task1());$c->start(task2());function task1(){ global $i; echo "wait start" . PHP_EOL; while ($i-- > 0) { yield; } echo "wait end" . PHP_EOL;};function task2(){ echo "Hello " . PHP_EOL; yield; echo "world!" . PHP_EOL;} 结果：
wait start
Hello
world!
//等待几秒，但不阻塞
wait end
希望本文所述对大家PHP程序设计有所帮助。
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