(PHP 8 >= 8.2.0)
curl_upkeep — Performs any connection upkeep checks
Available if built against libcurl >= 7.62.0.
Some protocols have "connection upkeep" mechanisms. These mechanisms usually send some traffic on existing connections in order to keep them alive; this can prevent connections from being closed due to overzealous firewalls, for example.
Connection upkeep is currently available only for HTTP/2 connections. A small amount of traffic is usually sent to keep a connection alive. HTTP/2 maintains its connection by sending a HTTP/2 PING frame.
Example #1 curl_upkeep() example
<?php
$url = "https://example.com";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTP_VERSION,CURL_HTTP_VERSION_2_0);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_UPKEEP_INTERVAL_MS, 200);
if (curl_exec($ch)) {
usleep(300);
var_dump(curl_upkeep($ch));
}
curl_close($ch);
?>