CURLOPT_DOH_URL(3)         Library Functions Manual         CURLOPT_DOH_URL(3)

NAME
       CURLOPT_DOH_URL - provide the DNS-over-HTTPS URL

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DOH_URL, char *URL);

DESCRIPTION
       Pass in a pointer to a URL for the DoH server to use for name
       resolving. The parameter should be a char pointer to a null-terminated
       string which must be a valid and correct HTTPS URL.

       libcurl does not validate the syntax or use this variable until the
       transfer is issued. Even if you set a crazy value here,
       curl_easy_setopt(3) still returns CURLE_OK.

       curl sends POST requests to the given DNS-over-HTTPS URL.

       To find the DoH server itself, which might be specified using a name,
       libcurl uses the default name lookup function. You can bootstrap that
       by providing the address for the DoH server with CURLOPT_RESOLVE(3).

       Disable DoH use again by setting this option to NULL.

INHERIT OPTIONS
       DoH lookups use SSL and some SSL settings from your transfer are
       inherited, like CURLOPT_SSL_CTX_FUNCTION(3).

       The hostname and peer certificate verification settings are not
       inherited but can be controlled separately via
       CURLOPT_DOH_SSL_VERIFYHOST(3) and CURLOPT_DOH_SSL_VERIFYPEER(3).

       A set CURLOPT_OPENSOCKETFUNCTION(3) callback is not inherited.

KNOWN BUGS
       Even when DoH is set to be used with this option, there are still some
       name resolves that are performed without it, using the default name
       resolver mechanism. This includes name resolves done for
       CURLOPT_INTERFACE(3), CURLOPT_FTPPORT(3), a proxy type set to
       CURLPROXY_SOCKS4 or CURLPROXY_SOCKS5 and probably some more.

DEFAULT
       NULL - there is no default DoH URL. If this option is not set, libcurl
       uses the default name resolver.

PROTOCOLS
       All

EXAMPLE
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
           curl_easy_setopt(curl, CURLOPT_DOH_URL, "https://dns.example.com");
           curl_easy_perform(curl);
         }
       }

AVAILABILITY
       Added in 7.62.0

RETURN VALUE
       Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was
       insufficient heap space.

       Note that curl_easy_setopt(3) does immediately parse the given string
       so when given a bad DoH URL, libcurl might not detect the problem until
       it later tries to resolve a name with it.

SEE ALSO
       CURLOPT_DNS_CACHE_TIMEOUT(3), CURLOPT_RESOLVE(3), CURLOPT_VERBOSE(3)

libcurl                          April 26 2024              CURLOPT_DOH_URL(3)