LINUX实操：php使用curl并发减少后端访问时间的方法分析

<?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}";
?>

<?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;
}
$url_arr=array(
   "taobao"=>"http://www.taobao.com",);
function microtime_float()
{
  list($usec,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}";
?>