Man page - curlopt_hstsreadfunction(3)

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Manual

CURLOPT_HSTSREADFUNCTION(3)

Library Functions Manual

CURLOPT_HSTSREADFUNCTION(3)

NAME

CURLOPT_HSTSREADFUNCTION - read 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] */
};
CURLSTScode hstsread(CURL *easy, struct curl_hstsentry *sts, void *clientp);
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 clientp argument with the CURLOPT_HSTSREADDATA(3) option or it is NULL.

When this callback is invoked, the sts pointer points to a populated struct: Copy the hostname 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 stops 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.

DEFAULT

NULL - no callback.

PROTOCOLS

This functionality affects http only

EXAMPLE

struct priv {


  void *custom;
};
static CURLSTScode hsts_cb(CURL *easy, struct curl_hstsentry *sts,


                           void *clientp)
{


  /* populate the struct as documented */


  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_HSTSREADFUNCTION, hsts_cb);


    /* pass in suitable argument to the callback */


    curl_easy_setopt(curl, CURLOPT_HSTSREADDATA, &my_stuff);


    res = curl_easy_perform(curl);


  }
}

AVAILABILITY

Added in curl 7.74.0

RETURN VALUE

This returns CURLE_OK.