NAME

       CURLOPT_HSTSREADFUNCTION - read 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] */
       };

       CURLSTScode hstsread(CURL *easy, struct curl_hstsentry *sts, void *clientp);

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSREADFUNCTION, hstsread);

DESCRIPTION

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

       This  callback  function gets called by libcurl repeatedly when it populates the in-memory
       HSTS cache.

       Set the clientp argument with the CURLOPT_HSTSREADDATA(3) option or it is NULL.

       When this callback is invoked, the sts pointer points to a populated struct: Copy the host
       name   to   name   (no   longer   than   namelen  bytes).  Make  it  null-terminated.  Set
       includeSubDomains to TRUE or FALSE. Set expire to a date stamp or a zero length string for
       *forever* (wrong date stamp format might cause the name to not get accepted)

       The  callback  should  return CURLSTS_OK if it returns a name and is prepared to be called
       again (for another host) or CURLSTS_DONE if it has no entry to return. It can also  return
       CURLSTS_FAIL  to  signal  error.  Returning  CURLSTS_FAIL  stops  the  transfer from being
       performed and make CURLE_ABORTED_BY_CALLBACK get returned.

       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

       struct priv {
         void *custom;
       };

       static CURLSTScode hsts_cb(CURL *easy, struct curl_hstsentry *sts,
                                  void *clientp)
       {
         /* populate the struct as documented */
         return CURLSTS_OK;
       }

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           struct priv my_stuff;
           CURLcode res;

           /* set HSTS read callback */
           curl_easy_setopt(curl, CURLOPT_HSTSREADFUNCTION, hsts_cb);

           /* pass in suitable argument to the callback */
           curl_easy_setopt(curl, CURLOPT_HSTSREADDATA, &my_stuff);

           res = curl_easy_perform(curl);
         }
       }

AVAILABILITY

       Added in 7.74.0

RETURN VALUE

       This returns CURLE_OK.

SEE ALSO

       CURLOPT_HSTS(3),              CURLOPT_HSTS_CTRL(3),               CURLOPT_HSTSREADDATA(3),
       CURLOPT_HSTSWRITEFUNCTION(3)