PHP使用curl并发减少后端访问时间的方法

问题的引发

在我们平时的程序中有时候会出现同时访问几个接口的情况，我们都是用curl进行访问，而这种访问一般都是单个、顺序访问的。那么问题来咯，假如有3个接口，每个接口耗时500毫秒，这样三个接口就要花费1500毫秒了，这个问题很严重，严重影响了页面访问速度。

 

解决问题

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

 

看看单个，顺序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}";

?>

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"=>"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}";

?>

运行后的结果：耗时:0.316秒  很明显，时间减少了一半