pthreads_example.php

<?php
error_reporting(E_ALL);

class AsyncWebRequest extends Thread {
        public $url;
        public $num;
        public $data;

        public function __construct($url, $num){
                $this->url = $url;
                $this->num = $num;
        }

        public function run(){
                echo "Thread {$this->num} running\n";
                if (($url = $this->url)) {
                        /*
                        * If a large amount of data is being requested, you might want to
                        * fsockopen and read using usleep in between reads
                        */
                        $this->data = file_get_contents($url);
                } else printf("Thread #%lu was not provided a URL\n", $this->getThreadId());
        }
}

$clock_start = microtime(true);

$threads = [];
for ($i=0; $i<32; $i++) {
        $url = sprintf("http://www.google.com/?q=%s", rand()*10);
        $mythread = [
                'start' => microtime(true),
                'thread' => new AsyncWebRequest($url, $i),
                'num' => $i,
        ];
        $threads[] = $mythread;
        if ($mythread['thread']->start()) {
                printf("Thread $i took %f seconds to start\n", microtime(true)-$mythread['start']);
        } else {
                throw new Exception("Unable to start thread!");
        }
}

$work_time = 0;
$running_threads = count($threads);
while ($running_threads > 0) {
        foreach ($threads as $idx => $thread) {
                if (!$thread['thread']->isRunning()) {
                        $running_threads--;
                        // Remove thread from stack
                        unset($threads[$idx]);
                        $time = microtime(true)-$thread['start'];
                        $work_time += $time;
                        if ($thread['thread']->join()) {
                                printf("Thread {$thread['thread']->num} took $time seconds to finish receiving %d bytes\n", strlen($thread['thread']->data));
                        } else {
                                echo "Thread {$thread['thread']->num} took $time seconds to finish, request failed\n";
                        }
                }
        }
}

$clock_time = microtime(true) - $clock_start;

echo "Finished in $clock_time seconds with $work_time CPU seconds\n";