NAME

       CURLOPT_HSTS - HSTS cache file name

SYNOPSIS

       #include <curl/curl.h>

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

DESCRIPTION

       Make  the  filename point to a file name 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  will
       also  enable  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
       will simply start empty. Setting the file name to NULL or "" will only enable HSTS without
       reading from or writing to any file.

       If this option is set multiple times, libcurl will load cache entries from each given file
       but will only store 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  a
       includeSubDomain  entry  (if  the  entry is valid for all subdmains 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 file name

PROTOCOLS

       HTTPS and HTTP

EXAMPLE

       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_HSTS_CTRL(3), CURLOPT_ALTSVC(3), CURLOPT_RESOLVE(3),