Example analysis of foreach combined with curl to achieve multi-threading in PHP

This article mainly introduces the method of foreach combined with curl to realize multi-threading in PHP. It analyzes the principles and implementation techniques of foreach statement combined with curl loop call to simulate multi-threading in the form of examples. Friends in need can refer to it

Multi-threading is not supported by PHP, but we can use foreach to pseudo-multi-thread, but this pseudo-multi-threading is not necessarily faster than single-threading. Let’s take a look at an example.

When using the foreach statement to loop through image URLs and save all images locally through CURL, there is a problem that only one can be collected. Now we will summarize the method of combining foreach and CURL to make multiple URL requests.

Method 1: Loop request

$sr=array(url_1,url_2,url_3);
foreach ($sr as $k=>$v) {
 $curlPost=$v.'?f=传入参数';
 $ch = curl_init($curlPost) ;
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, true) ; // 获取数据返回
 curl_setopt($ch, CURLOPT_BINARYTRANSFER, true) ; // 在启用 CURLOPT_RETURNTRANSFER 时候将获取数据返回
 $data = curl_exec($ch) ;
 echo $k.&#39;##:&#39;.$data.&#39;<br>&#39;;
}
curl_close($ch);

What needs special attention in the above code is that curl_close must be placed in foreach If placed outside the end of the loop, there will be multiple IMGURLs as I mentioned above, and only one URL can be collected.

Method 2: Multi-threaded loop

<?php
multi_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(multi_threads_request(array(
 &#39;http://www.jb51.net&#39;,
 &#39;http://tools.jb51.net&#39;,
));

Here mainly uses curl_multi_init() to implement multiple URL requests. However, since PHP itself does not support multi-threading, the pseudo-multi-threading speed is It may not be faster than a single thread.

Summary: The above is the entire content of this article, I hope it will be helpful to everyone's learning.

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