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CURLOPT_HSTSWRITEFUNCTION(3)

Library Functions Manual

CURLOPT_HSTSWRITEFUNCTION(3)

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 is NULL. When the callback is invoked, the sts pointer points to a populated struct: Read the hostname 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 is 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 functionality affects http only

EXAMPLE

struct priv {
void *custom;
};

static CURLSTScode hswr_cb(CURL *easy, struct curl_hstsentry *sts,
struct curl_index *count, void *clientp)
{
/* save the passed in HSTS data somewhere */
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_HSTSWRITEFUNCTION, hswr_cb);

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

res = curl_easy_perform(curl);
}
}

AVAILABILITY

Added in curl 7.74.0

RETURN VALUE

This returns CURLE_OK.