Clever use of curl concurrency in PHP to reduce the time of obtaining third-party web content

Foreword:

In our daily programs, it is inevitable to access several interfaces at the same time. When we usually use curl to access, it is usually a single and sequential access. If there are 3 interfaces, each interface takes 500 milliseconds, then our three interfaces will take 1500 milliseconds. This problem is too headache and seriously affects the page access speed. Is it possible to increase the speed by concurrent access? Today I will briefly talk about using curl concurrency to improve page access speed. I hope you can give me more guidance.

1. Old curl access method and time-consuming statistics

<?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}";
?>

Time-consuming: 0.614 seconds

2. Curl concurrent access method and time-consuming statistics

<?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])) == &#39;&#39;) {
            $res[$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}";
?>

Time-consuming: 0.316 seconds Handsome Bar entire page access back-end interface Time saved in half