CURLOPT_HSTS(3)            Library Functions Manual            CURLOPT_HSTS(3)

NAME
       CURLOPT_HSTS - HSTS cache filename

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTS, char *filename);

DESCRIPTION
       Make the filename point to a filename to load an existing HSTS cache
       from, and to store the cache in when the easy handle is closed. Setting
       a file name with this option also enables HSTS for this handle (the
       equivalent of setting CURLHSTS_ENABLE with CURLOPT_HSTS_CTRL(3)).

       If the given file does not exist or contains no HSTS entries at
       startup, the HSTS cache simply starts empty. Setting the filename to
       NULL or "" only enables HSTS without reading from or writing to any
       file.

       If this option is set multiple times, libcurl loads cache entries from
       each given file but only stores the last used name for later writing.

FILE FORMAT
       The HSTS cache is saved to and loaded from a text file with one entry
       per physical line. Each line in the file has the following format:

       [host] [stamp]

       [host] is the domain name for the entry and the name is dot-prefixed if
       it is an entry valid for all subdomains to the name as well or only for
       the exact name.

       [stamp] is the time (in UTC) when the entry expires and it uses the
       format "YYYYMMDD HH:MM:SS".

       Lines starting with "#" are treated as comments and are ignored. There
       is currently no length or size limit.

DEFAULT
       NULL, no filename

PROTOCOLS
       HTTP

EXAMPLE
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_HSTS, "/home/user/.hsts-cache");
           curl_easy_perform(curl);
         }
       }

AVAILABILITY
       Added in 7.74.0

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

SEE ALSO
       CURLOPT_ALTSVC(3), CURLOPT_HSTS_CTRL(3), CURLOPT_RESOLVE(3)

libcurl                          April 26 2024                 CURLOPT_HSTS(3)