Unverified Commit 7b655fcb authored by Max Dymond's avatar Max Dymond Committed by Daniel Stenberg
Browse files

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
parent 6684653b

docs/libcurl/Makefile.inc

+1 −1
Original line number Diff line number Diff line
@@ -22,4 +22,4 @@ man_MANS = curl_easy_cleanup.3 curl_easy_getinfo.3 curl_easy_init.3 \ 
  curl_mime_data.3 curl_mime_data_cb.3 curl_mime_filedata.3              \

  curl_mime_filename.3 curl_mime_subparts.3                              \

  curl_mime_type.3 curl_mime_headers.3 curl_mime_encoder.3 libcurl-env.3 \

  libcurl-security.3
 
  libcurl-security.3 curl_easy_conn_upkeep.3

docs/libcurl/curl_easy_conn_upkeep.3

0 → 100644
+77 −0
Original line number Diff line number Diff line 
.\" **************************************************************************

.\" *                                  _   _ ____  _

.\" *  Project                     ___| | | |  _ \| |

.\" *                             / __| | | | |_) | |

.\" *                            | (__| |_| |  _ <| |___

.\" *                             \___|\___/|_| \_\_____|

.\" *

.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, 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 <curl/curl.h>



.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

docs/libcurl/curl_easy_setopt.3

+3 −0
Original line number Diff line number Diff line
@@ -480,6 +480,9 @@ Shuffle addresses before use. See \fICURLOPT_DNS_SHUFFLE_ADDRESSES(3)\fP 
Timeout for waiting for the server's connect back to be accepted. See \fICURLOPT_ACCEPTTIMEOUT_MS(3)\fP

.IP CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS

Timeout for happy eyeballs. See \fICURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS(3)\fP

.IP CURLOPT_CONN_UPKEEP_INTERVAL_MS

Sets the interval at which connection upkeep are performed. See

\fICURLOPT_CONN_UPKEEP_INTERVAL_MS(3)\fP

.SH SSL and SECURITY OPTIONS

.IP CURLOPT_SSLCERT

Client cert. See \fICURLOPT_SSLCERT(3)\fP

docs/libcurl/opts/CURLOPT_CONN_UPKEEP_INTERVAL_MS.3

0 → 100644
+73 −0
Original line number Diff line number Diff line 
.\" **************************************************************************

.\" *                                  _   _ ____  _

.\" *  Project                     ___| | | |  _ \| |

.\" *                             / __| | | | |_) | |

.\" *                            | (__| |_| |  _ <| |___

.\" *                             \___|\___/|_| \_\_____|

.\" *

.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, 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 CURLOPT_CONN_UPKEEP_INTERVAL_MS 3 "31 Oct 2018" "libcurl 7.62.0" "curl_easy_setopt options"

.SH NAME

CURLOPT_CONN_UPKEEP_INTERVAL_MS \- connection upkeep interval

.SH SYNOPSIS

#include <curl/curl.h>



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

.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.



The user needs to explicitly call \fIcurl_easy_conn_upkeep(3)\fP in order to

perform the upkeep work.



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.



.SH DEFAULT

CURL_UPKEEP_INTERVAL_DEFAULT (currently defined as 60000L, which is 60 seconds)

.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

.SH AVAILABILITY

Added in 7.62.0

.SH RETURN VALUE

Returns CURLE_OK

docs/libcurl/opts/Makefile.inc

+1 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ man_MANS = \ 
  CURLOPT_CHUNK_END_FUNCTION.3                  \

  CURLOPT_CLOSESOCKETDATA.3                     \

  CURLOPT_CLOSESOCKETFUNCTION.3                 \

  CURLOPT_CONN_UPKEEP_INTERVAL_MS.3             \

  CURLOPT_CONNECTTIMEOUT.3                      \

  CURLOPT_CONNECTTIMEOUT_MS.3                   \

  CURLOPT_CONNECT_ONLY.3                        \