use php curl_multi_* to perform http requests

request_parallely.php

<?php
interface HandleIterator {
    public function getNextHandle();
    public function dataCallback($data);
}
class IndexHandleIterator implements HandleIterator{
    private $curl;
    private $count;
    public function __construct(){
        $this->curl = curl_init("http://localhost/index.php");
        $this->count = 0;
        curl_setopt($this->curl,CURLOPT_RETURNTRANSFER,true);
    }
    public function getNextHandle(){
        if($this->count > 1000){
            return null;
        }
        $this->count ++;
        $handle = curl_copy_handle($this->curl);
        return $handle;
    }
    public function dataCallback($data){
        echo $data;
    }
}
function request_parallelly(HandleIterator $handleIterator,$window_size=10){
    $multi = curl_multi_init();
    for($i = 0; $i < $window_size;$i ++){
        curl_multi_add_handle($multi,$handleIterator->getNextHandle());
    }
    //$time = microtime(true);
    do{
        while(($execrun = curl_multi_exec($multi, $running)) == CURLM_CALL_MULTI_PERFORM){ }
        if($execrun != CURLM_OK){
            break;
        }
        while($info = curl_multi_info_read($multi)) {
            $handle = $info['handle'];
            call_user_func([$handleIterator,'dataCallback'],curl_multi_getcontent($handle));
            curl_multi_remove_handle($multi,$handle);
            $nextHandle = $handleIterator->getNextHandle();
            if(!empty($nextHandle)){
                curl_multi_add_handle($multi,$nextHandle);
            }
            curl_close($handle);
        }
        //
        if($running){ //如果这一批还没执行完
            //阻塞,减少cpu占用
            curl_multi_select($multi);
        }
    }while($running);
    //echo microtime(true) -$time;
    curl_multi_close($multi);
}
function request_one_by_one($iterator){
    while(1){
        $handle = $iterator->getNextHandle();
        if(empty($handle)){
            break;
        }
        call_user_func([$iterator,'dataCallback'],curl_exec($handle));
    }
}
//test
$iterator = new IndexHandleIterator();
$start = microtime(true);
request_parallelly($iterator);
//request_one_by_one($iterator);
echo microtime(true) - $start;