curl_multi_init()

(PHP 5, PHP 7)

返回一个新cURL批处理句柄

说明

curl_multi_init(void): resource

允许并行地处理批处理cURL句柄。

参数

此函数没有参数。

返回值

成功时返回一个cURL批处理句柄，失败时返回FALSE。

范例

curl_multi_init() example

这个范例将会创建2个cURL句柄，把它们加到批处理句柄，然后并行地运行它们。

<?php
// 创建一对cURL资源
$ch1 = curl_init();
$ch2 = curl_init();
// 设置URL和相应的选项
curl_setopt($ch1, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch1, CURLOPT_HEADER, 0);
curl_setopt($ch2, CURLOPT_URL, "http://www.php.net/");
curl_setopt($ch2, CURLOPT_HEADER, 0);
// 创建批处理cURL句柄
$mh = curl_multi_init();
// 增加2个句柄
curl_multi_add_handle($mh,$ch1);
curl_multi_add_handle($mh,$ch2);
$running=null;
// 执行批处理句柄
do {
    usleep(10000);
    curl_multi_exec($mh,$running);
} while ($running > 0);
// 关闭全部句柄
curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);
curl_multi_close($mh);
?>

参见

• curl_init()初始化 cURL 会话
• curl_multi_close()关闭一组cURL句柄

Here's an easier to follow example, From : http://arguments.callee.info/2010/02/21/multiple-curl-requests-with-php/
// build the individual requests, but do not execute them
$ch_1 = curl_init('http://webservice.one.com/');
$ch_2 = curl_init('http://webservice.two.com/');
curl_setopt($ch_1, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch_2, CURLOPT_RETURNTRANSFER, true);
 
// build the multi-curl handle, adding both $ch
$mh = curl_multi_init();
curl_multi_add_handle($mh, $ch_1);
curl_multi_add_handle($mh, $ch_2);
 
// execute all queries simultaneously, and continue when all are complete
 $running = null;
 do {
  curl_multi_exec($mh, $running);
 } while ($running);
//close the handles
curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);
curl_multi_close($mh);
 
// all of our requests are done, we can now access the results
$response_1 = curl_multi_getcontent($ch_1);
$response_2 = curl_multi_getcontent($ch_2);
echo "$response_1 $response_2"; // output results

According to https://bugs.php.net/bug.php?id=61141:
On Windows setups using libcurl version 7.24 or later (which seems to correspond to PHP 5.3.10 or later), you may find that curl_multi_select() always returns -1, causing the example code in the documentation to timeout. This is, apparently, not strictly a bug: according to the libcurl documentation, you should add your own sleep if curl_multi_select returns -1.
Therefore, in order to work correctly on Windows for PHP 5.3.10+, the second loop in the example code should look something like the following:
<?php
while ($active && $mrc == CURLM_OK) {
  if (curl_multi_select($mh) == -1) {
    usleep(100);
  }
  do {
    $mrc = curl_multi_exec($mh, $active);
  } while ($mrc == CURLM_CALL_MULTI_PERFORM);
}
?>

One of the URLs used in the first example on this page (lxr.php.net) now gives a proxy error.
If you're using this first script example, replace with a different URL.

Simulate multiple threads request:
<?php
function multiple_threads_request($nodes){
    $mh = curl_multi_init();
    $curl_array = array();
    foreach($nodes as $i => $url)
    {
      $curl_array[$i] = curl_init($url);
      curl_setopt($curl_array[$i], CURLOPT_RETURNTRANSFER, true);
      curl_multi_add_handle($mh, $curl_array[$i]);
    }
    $running = NULL;
    do {
      usleep(10000);
      curl_multi_exec($mh,$running);
    } while($running > 0);
    
    $res = array();
    foreach($nodes as $i => $url)
    {
      $res[$url] = curl_multi_getcontent($curl_array[$i]);
    }
    
    foreach($nodes as $i => $url){
      curl_multi_remove_handle($mh, $curl_array[$i]);
    }
    curl_multi_close($mh);    
    return $res;
}
print_r(muti_thread_request(array(
  'http://www.example.com',
  'http://www.example.net',
)));
?>

http://github.com/jmathai/epicode/tree/master/php/EpiCurl.php
If you fire off 10 curl requests in parallel you don't have to wait for all of them to be finished before accessing one which is already finished.