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

       This functionality affects http only

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 curl 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)