NAME

       CURLOPT_HSTSWRITEFUNCTION - write callback for HSTS hosts

SYNOPSIS

       #include <curl/curl.h>

       struct curl_hstsentry {
         char *name;
         size_t namelen;
         unsigned int includeSubDomains:1;
         char expire[18]; /* YYYYMMDD HH:MM:SS [null-terminated] */
       };

       struct curl_index {
         size_t index; /* the provided entry's "index" or count */
         size_t total; /* total number of entries to save */
       };

       CURLSTScode hstswrite(CURL *easy, struct curl_hstsentry *sts,
                             struct curl_index *count, void *clientp);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSWRITEFUNCTION, hstswrite);

DESCRIPTION

       Pass a pointer to your callback function, as the prototype shows above.

       This callback function gets called by libcurl repeatedly to allow the application to store
       the in-memory HSTS cache when libcurl is about to discard it.

       Set the clientp argument with the CURLOPT_HSTSWRITEDATA(3) option or it will be NULL.

       When the callback is invoked, the sts pointer points to a populated struct: Read the  host
       name  to 'name' (it is namelen bytes long and null terminated. The includeSubDomains field
       is non-zero if the entry matches subdomains. The expire  string  is  a  date  stamp  null-
       terminated string using the syntax YYYYMMDD HH:MM:SS.

       The  callback  should return CURLSTS_OK if it succeeded and is prepared to be called again
       (for another host) or CURLSTS_DONE if there's nothing more  to  do.  It  can  also  return
       CURLSTS_FAIL to signal error.

       This option does not enable HSTS, you need to use CURLOPT_HSTS_CTRL(3) to do that.

DEFAULT

       NULL - no callback.

PROTOCOLS

       This feature is only used for HTTP(S) transfer.

EXAMPLE

       {
         /* set HSTS read callback */
         curl_easy_setopt(curl, CURLOPT_HSTSWRITEFUNCTION, hstswrite);

         /* pass in suitable argument to the callback */
         curl_easy_setopt(curl, CURLOPT_HSTSWRITEDATA, &hstspreload[0]);

         result = curl_easy_perform(curl);
       }

AVAILABILITY

       Added in 7.74.0

RETURN VALUE

       This will return CURLE_OK.

SEE ALSO

       CURLOPT_HSTSWRITEDATA(3),          CURLOPT_HSTSWRITEFUNCTION(3),          CURLOPT_HSTS(3),
       CURLOPT_HSTS_CTRL(3),