PHP中巧用curl 并发减少获取第三方网页内容时间

前言：

在我们平时的程序中难免出现同时访问几个接口的情况，平时我们用curl进行访问的时候，一般都是单个、顺序访问，假如有3个接口，每个接口耗时500毫秒那么我们三个接口就要花费1500毫秒了，这个问题太头疼了严重影响了页面访问速度，有没有可能并发访问来提高速度呢？今天就简单的说一下，利用curl并发来提高页面访问速度， 希望大家多指导。

1、老的curl访问方式以及耗时统计

<?php
function curl_fetch($url, $timeout=3){
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $data = curl_exec($ch);
    $errno = curl_errno($ch);
    if ($errno>0) {
        $data = false;
    }
    curl_close($ch);
    return $data;
}
function microtime_float()
{
   list($usec, $sec) = explode(" ", microtime());
   return ((float)$usec + (float)$sec);
}
$url_arr=array(
     "taobao"=>"http://www.taobao.com",
     "sohu"=>"http://www.sohu.com",
     "sina"=>"http://www.sina.com.cn",
);
$time_start = microtime_float();
$data=array();
foreach ($url_arr as $key=>$val)
{
     $data[$key]=curl_fetch($val);
}
$time_end = microtime_float();
$time = $time_end - $time_start;
echo "耗时:{$time}";
?>

耗时:0.614秒

2、curl并发访问方式以及耗时统计

<?php
function curl_multi_fetch($urlarr=array()){
    $result=$res=$ch=array();
    $nch = 0;
    $mh = curl_multi_init();
    foreach ($urlarr as $nk => $url) {
        $timeout=2;
        $ch[$nch] = curl_init();
        curl_setopt_array($ch[$nch], array(
            CURLOPT_URL => $url,
            CURLOPT_HEADER => false,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT => $timeout,
        ));
        curl_multi_add_handle($mh, $ch[$nch]);
        ++$nch;
    }
    /* wait for performing request */
    do {
        $mrc = curl_multi_exec($mh, $running);
    } while (CURLM_CALL_MULTI_PERFORM == $mrc);
 
    while ($running && $mrc == CURLM_OK) {
        // wait for network
        if (curl_multi_select($mh, 0.5) > -1) {
            // pull in new data;
            do {
                $mrc = curl_multi_exec($mh, $running);
            } while (CURLM_CALL_MULTI_PERFORM == $mrc);
        }
    }
 
    if ($mrc != CURLM_OK) {
        error_log("CURL Data Error");
    }
 
    /* get data */
    $nch = 0;
    foreach ($urlarr as $moudle=>$node) {
        if (($err = curl_error($ch[$nch])) == '') {
            $res[$nch]=curl_multi_getcontent($ch[$nch]);
            $result[$moudle]=$res[$nch];
        }
        else
        {
            error_log("curl error");
        }
        curl_multi_remove_handle($mh,$ch[$nch]);
        curl_close($ch[$nch]);
        ++$nch;
    }
    curl_multi_close($mh);
    return  $result;
}
$url_arr=array(
     "taobao"=>"http://www.taobao.com",
     "sohu"=>"http://www.sohu.com",
     "sina"=>"http://www.sina.com.cn",
     );
function microtime_float()
{
   list($usec, $sec) = explode(" ", microtime());
   return ((float)$usec + (float)$sec);
}
$time_start = microtime_float();
$data=curl_multi_fetch($url_arr);
$time_end = microtime_float();
$time = $time_end - $time_start;
 echo "耗时:{$time}";
?>

耗时:0.316秒 帅气吧整个页面访问后端接口的时间节省了一半

原文：http://www.searchtb.com/2010/12/using-multicurl-to-improve-performance.html