GNURLOPT_UPKEEP_INTERVAL_MS(3)

okay so bestie 💖 welcome to the GNURLOPT_UPKEEP_INTERVAL_MS(3) page — the header shows it as GNURLOPT_U...INTERVAL_MS(3) — and it lives in the curl_easy_setopt options manual. We're talking connection upkeep interval, no cap ✨

✨ NAME ✨

• CURLOPT_UPKEEP_INTERVAL_MS — connection upkeep interval. that's the whole vibe 💅

🦋 SYNOPSIS 🦋

#include <gnurl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_UPKEEP_INTERVAL_MS, long
       upkeep_interval_ms);

💅 DESCRIPTION 💅

okay so some protocols have these things called "connection upkeep" mechanisms. These mechanisms usually send some traffic on existing connections in order to keep them alive — and that can prevent connections from being closed due to overzealous firewalls, for example. literally the firewall is being extra 🙄

The user needs to explicitly call curl_easy_upkeep(3) in order to perform the upkeep work. yes bestie, you gotta call it yourself — it is not just vibing on its own.

Currently the only protocol with a connection upkeep mechanism is HTTP/2: when the connection upkeep interval is exceeded and curl_easy_upkeep(3) is called, an HTTP/2 PING frame is sent on the connection. iconic behavior tbh 🫶

🎀 DEFAULT 🎀

CURL_UPKEEP_INTERVAL_DEFAULT — currently defined as 60000L, which is 60 seconds. so a whole minute, bestie ⏳

🌸 EXAMPLE 🌸

CURL *curl = curl_easy_init();
if(curl) {
  /* Make a connection to an HTTP/2 server. */
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

  /* Set the interval to 30000ms / 30s */
  curl_easy_setopt(curl, CURLOPT_UPKEEP_INTERVAL_MS, 30000L);

  curl_easy_perform(curl);

  /* Perform more work here. */

  /* While the connection is being held open, curl_easy_upkeep() can be
     called. If curl_easy_upkeep() is called and the time since the last
     upkeep exceeds the interval, then an HTTP/2 PING is sent. */
  curl_easy_upkeep(curl);

  /* Perform more work here. */

  /* always cleanup */
  curl_easy_cleanup(curl);
}

⭐ AVAILABILITY ⭐

Added in 7.62.0 ✨

💖 RETURN VALUE 💖

Returns CURLE_OK — that's the whole return value, periodt 💅

okay bye bestie 🫶 — this page is from libcurl 7.62.0, dated 31 Oct 2018, and it's the GNURLOPT_U...INTERVAL_MS(3) page. slay ✨