我发现这个软件包非常有用，非常简单:https://github.com/amphp/parallel-functions

<?php

use function Amp\ParallelFunctions\parallelMap;
use function Amp\Promise\wait;

$responses = wait(parallelMap([
    'https://google.com/',
    'https://github.com/',
    'https://stackoverflow.com/',
], function ($url) {
    return file_get_contents($url);
}));

它将并行加载所有3个url。 您还可以在闭包中使用类实例方法。

例如，我使用Laravel扩展基于这个包https://github.com/spatie/laravel-collection-macros#parallelmap

这是我的代码:

    /**
     * Get domains with all needed data
     */
    protected function getDomainsWithdata(): Collection
    {
        return $this->opensrs->getDomains()->parallelMap(function ($domain) {
            $contact = $this->opensrs->getDomainContact($domain);
            $contact['domain'] = $domain;
            return $contact;
        }, 10);
    }

它在10个并行线程中加载所有需要的数据，而不是在没有异步的情况下50秒，它在8秒内完成。

超时可以设置为毫秒， 参见http://www.php.net/manual/en/function.curl-setopt中的“CURLOPT_CONNECTTIMEOUT_MS”

这是我自己的PHP函数，当我做POST到任何页面的特定URL .... 示例:my Function的***用法…

    <?php
        parse_str("email=myemail@ehehehahaha.com&subject=this is just a test");
        $_POST['email']=$email;
        $_POST['subject']=$subject;
        echo HTTP_POST("http://example.com/mail.php",$_POST);***

    exit;
    ?>
    <?php
    /*********HTTP POST using FSOCKOPEN **************/
    // by ArbZ

function HTTP_Post($URL,$data, $referrer="") {

    // parsing the given URL
    $URL_Info=parse_url($URL);

    // Building referrer
    if($referrer=="") // if not given use this script as referrer
        $referrer=$_SERVER["SCRIPT_URI"];

    // making string from $data
    foreach($data as $key=>$value)
        $values[]="$key=".urlencode($value);
        $data_string=implode("&",$values);

    // Find out which port is needed - if not given use standard (=80)
    if(!isset($URL_Info["port"]))
        $URL_Info["port"]=80;

    // building POST-request: HTTP_HEADERs
    $request.="POST ".$URL_Info["path"]." HTTP/1.1\n";
    $request.="Host: ".$URL_Info["host"]."\n";
    $request.="Referer: $referer\n";
    $request.="Content-type: application/x-www-form-urlencoded\n";
    $request.="Content-length: ".strlen($data_string)."\n";
    $request.="Connection: close\n";
    $request.="\n";
    $request.=$data_string."\n";

    $fp = fsockopen($URL_Info["host"],$URL_Info["port"]);
    fputs($fp, $request);
    while(!feof($fp)) {
        $result .= fgets($fp, 128);
    }
    fclose($fp); //$eco = nl2br();


    function getTextBetweenTags($string, $tagname) {
        $pattern = "/<$tagname ?.*>(.*)<\/$tagname>/";
        preg_match($pattern, $string, $matches);
        return $matches[1];
    }
    //STORE THE FETCHED CONTENTS to a VARIABLE, because its way better and fast...
    $str = $result;
    $txt = getTextBetweenTags($str, "span"); $eco = $txt;  $result = explode("&",$result);
    return $result[1];
    <span style=background-color:LightYellow;color:blue>".trim($_GET['em'])."</span>
    </pre> "; 
}
</pre>

您可以使用exec()来调用一些可以执行HTTP请求的东西，如wget，但必须将程序的所有输出指向某个地方，如文件或/dev/null，否则PHP进程将等待该输出。

如果你想把进程和apache线程完全分开，可以尝试这样做(我不确定，但我希望你能明白):

exec('bash -c "wget -O (url goes here) > /dev/null 2>&1 &"');

这不是一项很好的业务，您可能需要类似cron作业的东西来调用heartbeat脚本，该脚本轮询实际的数据库事件队列来执行真正的异步事件。

您可以使用这个库:https://github.com/stil/curl-easy

这很简单:

<?php
$request = new cURL\Request('http://yahoo.com/');
$request->getOptions()->set(CURLOPT_RETURNTRANSFER, true);

// Specify function to be called when your request is complete
$request->addListener('complete', function (cURL\Event $event) {
    $response = $event->response;
    $httpCode = $response->getInfo(CURLINFO_HTTP_CODE);
    $html = $response->getContent();
    echo "\nDone.\n";
});

// Loop below will run as long as request is processed
$timeStart = microtime(true);
while ($request->socketPerform()) {
    printf("Running time: %dms    \r", (microtime(true) - $timeStart)*1000);
    // Here you can do anything else, while your request is in progress
}

下面你可以看到上面例子的控制台输出。 它将显示简单的实时时钟，指示请求正在运行的时间:

你可以在PHP中使用非阻塞套接字和pecl扩展之一:

http://php.net/event http://php.net/libevent http://php.net/ev https://github.com/m4rw3r/php-libev

您可以使用库，它为您的代码和pecl扩展之间提供了一个抽象层:https://github.com/reactphp/event-loop

您还可以使用基于前面库的异步http-client: https://github.com/reactphp/http-client

查看ReactPHP的其他库:http://reactphp.org

使用异步模型时要小心。 我推荐在youtube上看这个视频:http://www.youtube.com/watch?v=MWNcItWuKpI