CURLOPT_HSTS(3)            curl_easy_setopt options            CURLOPT_HSTS(3)

NAME
       CURLOPT_HSTS - set HSTS cache file name

SYNOPSIS
       #include <curl/curl.h>

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

EXPERIMENTAL
       Warning: this feature is early code and is marked as experimental. It
       can only be enabled by explicitly telling configure with --enable-hsts.
       You are advised to not ship this in production before the experimental
       label is removed.

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 _HSTS_CTRL&section=3">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),

libcurl 7.77.0                 November 13, 2020               CURLOPT_HSTS(3)