From 7b655fcbadffc3a0297466f1527e05d4a8efe6b2 Mon Sep 17 00:00:00 2001 From: Max Dymond Date: Wed, 18 Apr 2018 16:40:17 +0100 Subject: upkeep: add a connection upkeep API: curl_easy_conn_upkeep() Add functionality so that protocols can do custom keepalive on their connections, when an external API function is called. Add docs for the new options in 7.62.0 Closes #1641 --- docs/libcurl/curl_easy_conn_upkeep.3 | 77 ++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 docs/libcurl/curl_easy_conn_upkeep.3 (limited to 'docs/libcurl/curl_easy_conn_upkeep.3') diff --git a/docs/libcurl/curl_easy_conn_upkeep.3 b/docs/libcurl/curl_easy_conn_upkeep.3 new file mode 100644 index 000000000..f95f0ab22 --- /dev/null +++ b/docs/libcurl/curl_easy_conn_upkeep.3 @@ -0,0 +1,77 @@ +.\" ************************************************************************** +.\" * _ _ ____ _ +.\" * Project ___| | | | _ \| | +.\" * / __| | | | |_) | | +.\" * | (__| |_| | _ <| |___ +.\" * \___|\___/|_| \_\_____| +.\" * +.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, , et al. +.\" * +.\" * This software is licensed as described in the file COPYING, which +.\" * you should have received as part of this distribution. The terms +.\" * are also available at https://curl.haxx.se/docs/copyright.html. +.\" * +.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell +.\" * copies of the Software, and permit persons to whom the Software is +.\" * furnished to do so, under the terms of the COPYING file. +.\" * +.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY +.\" * KIND, either express or implied. +.\" * +.\" ************************************************************************** +.\" +.TH curl_easy_conn_upkeep 3 "31 Oct 2018" "libcurl 7.62.0" "libcurl Manual" +.SH NAME +curl_easy_conn_upkeep - Perform any connection upkeep checks. +.SH SYNOPSIS +.B #include + +.BI "CURLcode curl_easy_conn_upkeep(CURL *" handle ");" +.SH DESCRIPTION + +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. + +Currently the only protocol with a connection upkeep mechanism is HTTP/2: when +the connection upkeep interval is exceeded and \fIcurl_easy_conn_upkeep(3)\fP +is called, an HTTP/2 PING frame is sent on the connection. + +This function must be explicitly called in order to perform the upkeep work. +The connection upkeep interval is set with +\fICURLOPT_CONN_UPKEEP_INTERVAL_MS(3)\fP. + +.SH AVAILABILITY +Added in 7.62.0. +.SH RETURN VALUE +On success, returns \fBCURLE_OK\fP. + +On failure, returns the appropriate error code. + +.SH EXAMPLE +.nf +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_CONN_UPKEEP_INTERVAL_MS, 30000L); + + curl_easy_perform(curl); + + /* Perform more work here. */ + + /* While the connection is being held open, curl_easy_conn_upkeep() can be + called. If curl_easy_conn_upkeep() is called and the time since the last + upkeep exceeds the interval, then an HTTP/2 PING is sent. */ + curl_easy_conn_upkeep(curl); + + /* Perform more work here. */ + + /* always cleanup */ + curl_easy_cleanup(curl); +} + +.fi -- cgit v1.2.3