curl / libcurl / API / curl_easy_setopt / CURLOPT_HSTS_CTRL

CURLOPT_HSTS_CTRL explained

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

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

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.