NAME¶

CURLOPT_HSTS_CTRL - control HSTS behavior

SYNOPSIS¶

#include <curl/curl.h>
#define CURLHSTS_ENABLE       (1<<0)
#define CURLHSTS_READONLYFILE (1<<1)
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTS_CTRL, long bitmask);

DESCRIPTION¶

HSTS (HTTP Strict Transport Security) means that an HTTPS server can instruct the client to not contact it again over clear-text HTTP for a certain period into the future. libcurl then automatically redirects HTTP attempts to such hosts to instead use HTTPS. This is done by libcurl retaining this knowledge in an in-memory cache.

Populate the long bitmask with the correct set of features to instruct libcurl how to handle HSTS for the transfers using this handle.

BITS¶

CURLHSTS_ENABLE

Enable the in-memory HSTS cache for this handle.

CURLHSTS_READONLYFILE

Make the HSTS file (if specified) read-only - makes libcurl not save the cache to the file when closing the handle.

DEFAULT¶

0

PROTOCOLS¶

This functionality affects http only

EXAMPLE¶

int main(void)
{


  CURL *curl = curl_easy_init();


  if(curl) {


    curl_easy_setopt(curl, CURLOPT_HSTS_CTRL, (long)CURLHSTS_ENABLE);


    curl_easy_perform(curl);


  }
}

AVAILABILITY¶

Added in curl 7.74.0

RETURN VALUE¶

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).

SEE ALSO¶

CURLOPT_ALTSVC(3), CURLOPT_CONNECT_TO(3), CURLOPT_HSTS(3), CURLOPT_RESOLVE(3)