本文实例讲述了php使用curl并发减少后端访问时间的方法。分享给大家供大家参考，具体如下：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，

1、老的curl访问方式以及耗时统计

<?php
function curl_fet ch ($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"=>"",
 "sohu"=>"",
 "sina"=>"",
 );
 $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}";
?>
 

以上代码运行结果如下：耗时:0.614秒 显然这是不可取的。来看看并发的效果

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;
}
$url_arr=array(
 "taobao"=>"",
 "sohu"=>"",
 "sina"=>"",
 );
function microtime_float(){
 list($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}";
?>
 

运行后的结果：耗时:0.316秒 很明显，时间减少了一半

面是一个例子，我们在开发中对接接口的时候经常会遇到，所以在关于php性能方面，这类问题还是要引起关注的！

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