1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_HSTS_CTRL 5Section: 3 6Source: libcurl 7Protocol: 8 - HTTP 9See-also: 10 - CURLOPT_ALTSVC (3) 11 - CURLOPT_CONNECT_TO (3) 12 - CURLOPT_HSTS (3) 13 - CURLOPT_RESOLVE (3) 14--- 15 16# NAME 17 18CURLOPT_HSTS_CTRL - control HSTS behavior 19 20# SYNOPSIS 21 22~~~c 23#include <curl/curl.h> 24 25#define CURLHSTS_ENABLE (1<<0) 26#define CURLHSTS_READONLYFILE (1<<1) 27 28CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTS_CTRL, long bitmask); 29~~~ 30 31# DESCRIPTION 32 33HSTS (HTTP Strict Transport Security) means that an HTTPS server can instruct 34the client to not contact it again over clear-text HTTP for a certain period 35into the future. libcurl then automatically redirects HTTP attempts to such 36hosts to instead use HTTPS. This is done by libcurl retaining this knowledge 37in an in-memory cache. 38 39Populate the long *bitmask* with the correct set of features to instruct 40libcurl how to handle HSTS for the transfers using this handle. 41 42# BITS 43 44## CURLHSTS_ENABLE 45 46Enable the in-memory HSTS cache for this handle. 47 48## CURLHSTS_READONLYFILE 49 50Make the HSTS file (if specified) read-only - makes libcurl not save the cache 51to the file when closing the handle. 52 53# DEFAULT 54 550. HSTS is disabled by default. 56 57# EXAMPLE 58 59~~~c 60int main(void) 61{ 62 CURL *curl = curl_easy_init(); 63 if(curl) { 64 curl_easy_setopt(curl, CURLOPT_HSTS_CTRL, (long)CURLHSTS_ENABLE); 65 curl_easy_perform(curl); 66 } 67} 68~~~ 69 70# AVAILABILITY 71 72Added in 7.74.0 73 74# RETURN VALUE 75 76Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. 77
