php基于协程实现异步的方法分析


						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：http://github.com/recoilphp/recoil

先安装：





composer require recoil/recoil







执行：





<?php

//recoil.php

include __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



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