pcntl 模块（非 Unix 类系统不支持此模块）
一个 PHP 多进程简单例子大概是这个样子：
// 5 个子进程处理任务
for ($i = 0; $i < 5; $i++) {
$pid = pcntl_fork();
if ($pid == -1) {
die("could not fork");
} elseif ($pid) {
echo "I'm the Parent $i\n";
} else { // 子进程处理
echo "I'm the Child $i\n";
// 业务处理
exit($i); // 一定要注意退出子进程，否则 pcntl_fork() 会被子进程再 fork，带来处理上的影响。
}
}
// 等待子进程执行结束
while (pcntl_waitpid(0, $status) != -1) {
$status = pcntl_wexitstatus($status);
echo "Child $status completed\n";
}
当然实际应用中我们不能够这样输出代码，不够健壮，也不够优雅，我所以找了个基于 pcntl 封装的扩展包来使用。
spatie/async - 基于 pcntl 封装的扩展包
以下是我使用 spatie/async 来优化一个多进程请求的例子
原代码（耗时 20s 左右）- github.com/guanguans/m…
/**
* @param string $keyword
*
* @return array
*/
public function searchAll(string $keyword): array
{
$songAll = [];
foreach ($this->platforms as $platform) {
$songAll = array_merge($songAll, $this->search($platform, $keyword));
}
return $songAll;
}
/**
* @param string $platform
* @param string $keyword
*
* @return mixed
*/
public function search(string $platform, string $keyword)
{
$meting = $this->getMeting($platform);
$songs = json_decode($meting->format()->search($keyword), true);
foreach ($songs as $key => &$song) {
$detail = json_decode($meting->format()->url($song['url_id']), true);
if (empty($detail['url'])) {
unset($songs[$key]);
}
$song = array_merge($song, $detail);
}
unset($song);
return $songs;
}
改进后（耗时 4s 左右）- github.com/guanguans/m…
/**
* @param string $keyword
*
* @return array
*/
public function searchAll(string $keyword): array
{
$songAll = [];
$pool = Pool::create();
foreach ($this->platforms as $platform) {
$pool->add(function () use ($platform, $keyword) {
return $this->search($platform, $keyword);
}, $this->getSerializedOutput())->then(function ($output) use (&$songAll) {
$songAll = array_merge($songAll, $output);
})->catch(function (\Throwable $exception) {
exit($exception->getMessage());
});
}
$pool->wait();
return $songAll;
}
/**
* @return mixed
*/
public function search(string $platform, string $keyword)
{
$meting = $this->getMeting($platform);
$songs = json_decode($meting->format()->search($keyword), true);
$pool = Pool::create();
foreach ($songs as $key => &$song) {
$pool->add(function () use ($meting, $song) {
return json_decode($meting->format()->url($song['url_id']), true);
})->then(function ($output) use (&$songs, &$song, $key) {
$song = array_merge($song, $output);
if (empty($song['url'])) {
unset($songs[$key]);
}
})->catch(function (\Throwable $exception) {
exit($exception->getMessage());
});
}
unset($song);
$pool->wait();
return $songs;
}
