iw7-mod/deps/curl/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.md
2024-08-13 05:15:34 -04:00

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---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_HSTSWRITEFUNCTION
Section: 3
Source: libcurl
See-also:
- CURLOPT_HSTS (3)
- CURLOPT_HSTSWRITEDATA (3)
- CURLOPT_HSTSWRITEFUNCTION (3)
- CURLOPT_HSTS_CTRL (3)
---
# NAME
CURLOPT_HSTSWRITEFUNCTION - write callback for HSTS hosts
# SYNOPSIS
~~~c
#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 feature is only used for HTTP(S) transfer.
# EXAMPLE
~~~c
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 7.74.0
# RETURN VALUE
This returns CURLE_OK.