CURLOPT_HSTSWRITEFUNCTION(3)

1CURLOPT_HSTSWRITEFUNCTION(3)curl_easy_setopt optionsCURLOPT_HSTSWRITEFUNCTION(3)
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NAME

6       CURLOPT_HSTSWRITEFUNCTION - write callback for HSTS hosts
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SYNOPSIS

9       #include <curl/curl.h>
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11       CURLSTScode hstswrite(CURL *easy, struct curl_hstsentry *sts,
12                             struct curl_index *count, void *userp);
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14       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSWRITEFUNCTION, hstswrite);
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DESCRIPTION

17       Pass a pointer to your callback function, as the prototype shows above.
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19       This  callback  function gets called by libcurl repeatedly to allow the
20       application to store the in-memory HSTS cache when libcurl is about  to
21       discard it.
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23       Set  the  userp argument with the CURLOPT_HSTSWRITEDATA(3) option or it
24       will be NULL.
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26       When the callback is invoked, the sts pointer  points  to  a  populated
27       struct:  Read  the  host name to 'name' (it is 'namelen' bytes long and
28       null terminated. The 'includeSubDomains' field is non-zero if the entry
29       matches subdomains. The 'expire' string is a date stamp null-terminated
30       string using the syntax YYYYMMDD HH:MM:SS.
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32       The callback should return CURLSTS_OK if it succeeded and  is  prepared
33       to  be called again (for another host) or CURLSTS_DONE if there's noth‐
34       ing more to do. It can also return CURLSTS_FAIL to signal error.
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36       This option does not enable HSTS, you need to use  CURLOPT_HSTS_CTRL(3)
37       to do that.
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DEFAULT

40       NULL - no callback.
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PROTOCOLS

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

46       {
47         /* set HSTS read callback */
48         curl_easy_setopt(curl, CURLOPT_HSTSWRITEFUNCTION, hstswrite);
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50         /* pass in suitable argument to the callback */
51         curl_easy_setopt(curl, CURLOPT_HSTSWRITEDATA, &hstspreload[0]);
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53         result = curl_easy_perform(curl);
54       }
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AVAILABILITY

57       Added in 7.74.0
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RETURN VALUE

60       This will return CURLE_OK.
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