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CURLOPT_HSTSREADFUNCTION(3) curl_easy_setopt options CURLOPT_HSTSREADFUNCTION(3)

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);

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 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 doesn't 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_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),

September 16, 2021 libcurl 7.79.1