CURLOPT_HSTSREADFUNCTION(3)                           curl_easy_setopt options

NAME
       CURLOPT_HSTSREADFUNCTION - read callback for HSTS hosts

SYNOPSIS
       #include <curl/curl.h>

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

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

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
       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 userp argument with the _HSTSREADDATA&section=3">CURLOPT_HSTSREADDATA(3) option or it
       will be 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.

       This option doesn't enable HSTS, you need to use _HSTS_CTRL&section=3">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_HSTSREADFUNCTION, hstsread);

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

         result = curl_easy_perform(curl);
       }

AVAILABILITY
       Added in 7.74.0

RETURN VALUE
       This will return CURLE_OK.

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

libcurl 7.77.0                 November 4, 2020    CURLOPT_HSTSREADFUNCTION(3)