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_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

3、curl相关参数

curl_close — Close a cURL session

curl_copy_handle — Copy a cURL handle along with all of its preferences

curl_errno — Return the last error number

curl_error — Return a string containing the last error for the current session

curl_exec — Perform a cURL session

curl_getinfo — Get information regarding a specific transfer

curl_init — Initialize a cURL session

curl_multi_add_handle — Add a normal cURL handle to a cURL multi handle

curl_multi_close — Close a set of cURL handles

curl_multi_exec — Run the sub-connections of the current cURL handle

curl_multi_getcontent — Return the content of a cURL handle if CURLOPT_RETURNTRANSFER is set

curl_multi_info_read — Get information about the current transfers

curl_multi_init — Returns a new cURL multi handle

curl_multi_remove_handle — Remove a multi handle from a set of cURL handles

curl_multi_select — Wait for activity on any curl_multi connection

curl_setopt_array — Set multiple options for a cURL transfer

curl_setopt — Set an option for a cURL transfer

curl_version — Gets cURL version information

希望本文所述对大家PHP程序设计有所帮助。