Manpages - CURLOPT_HSTSREADFUNCTION.3

CURLOPT_HSTSREADFUNCTION - read callback for HSTS hosts

#include <curl/curl.h>

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

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

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 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. Returning CURLSTS_FAIL will stop 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.

NULL - no callback.

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

  {
    /* 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);
  }

Added in 7.74.0

This will return CURLE_OK.

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