Too many sockets open by cURL multi - php

Question

I am using cURL multi to get data from some websites. With code:
function getURL($ids)
{
global $mh;
$curl = array();
$response = array();
$n = count($ids);
for($i = 0; $i < $n; $i++) {
$id = $ids[$i];
$url = 'http://www.domain.com/?id='.$id;
// Init cURL
$curl[$i] = curl_init($url);
curl_setopt($curl[$i], CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl[$i], CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($curl[$i], CURLOPT_USERAGENT, 'Googlebot/2.1 (http://www.googlebot.com/bot.html)');
//curl_setopt($curl[$i], CURLOPT_FORBID_REUSE, true);
//curl_setopt($curl[$i], CURLOPT_HEADER, false);
curl_setopt($curl[$i], CURLOPT_HTTPHEADER, array(
'Connection: Keep-Alive',
'Keep-Alive: 300'
));
// Set to multi cURL
curl_multi_add_handle($mh, $curl[$i]);
}
// Execute
do {
curl_multi_exec($mh, $flag);
} while ($flag > 0);
// Get response
for($i = 1; $i < $n; $i++) {
// Get data
$id = $ids[$i];
$response[] = array(
'id' => $id,
'data' => curl_multi_getcontent($curl[$i])
);
// Remove handle
//curl_multi_remove_handle($mh, $curl[$i]);
}
// Reponse
return $response;
}
But, i have problem is cURL open too many sockets to connect to webserver. Each connection, cURL create new socket to webserver.
I want to current connection is keep-alive for next connection. I don't want that 100 URL then cURL must create 100 sockets to handle :(
Please help me. Thanks so much !

Answer 1

So don't open that many sockets. Modify your code to only open X sockets, and then repeatedly use those sockets until all of your $ids have been consumed. That or pass fewer $ids into the function to begin with.

Answer 2

I know, this is old, but the correct answer has not been given, yet, IMHO.
Please have a look at th CURLMOPT_MAX_TOTAL_CONNECTIONS option, which should solve your problem:
https://curl.se/libcurl/c/CURLMOPT_MAX_TOTAL_CONNECTIONS.html
Also make sure, that multiplexing via HTTP/2 is not disabled accidentally:
https://curl.se/libcurl/c/CURLMOPT_PIPELINING.html
Classical HTTP/1 pipelining is no longer supported by cURL, but cURL can still re-use an existing HTTP/1 connection to send a new request once the current request has finished on that connection.