Tribblix: manual page: CURLOPT

CURLOPT_HEADEROPT(3) Introduction to Library Functions CURLOPT_HEADEROPT(3)

NAME

CURLOPT_HEADEROPT - send HTTP headers to both proxy and host or
separately

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HEADEROPT, long bitmask);

DESCRIPTION

Pass a long that is a bitmask of options of how to deal with headers.
The two mutually exclusive options are:

CURLHEADER_UNIFIED - the headers specified in CURLOPT_HTTPHEADER(3)
are used in requests both to servers and proxies. With this option
enabled, CURLOPT_PROXYHEADER(3) does not have any effect.

CURLHEADER_SEPARATE - makes CURLOPT_HTTPHEADER(3) headers only get
sent to a server and not to a proxy. Proxy headers must be set with
CURLOPT_PROXYHEADER(3) to get used. Note that if a non-CONNECT
request is sent to a proxy, libcurl sends both server headers and
proxy headers. When doing CONNECT, libcurl sends
CURLOPT_PROXYHEADER(3) headers only to the proxy and then
CURLOPT_HTTPHEADER(3) headers only to the server.

DEFAULT

CURLHEADER_SEPARATE (changed in 7.42.1, used CURLHEADER_UNIFIED
before then)

PROTOCOLS

This functionality affects http only

EXAMPLE

int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode ret;
struct curl_slist *list;
list = curl_slist_append(NULL, "Shoesize: 10");
list = curl_slist_append(list, "Accept:");
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_PROXY, "http://localhost:8080");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);

/* HTTPS over a proxy makes a separate CONNECT to the proxy, so tell
libcurl to not send the custom headers to the proxy. Keep them
separate. */
curl_easy_setopt(curl, CURLOPT_HEADEROPT, CURLHEADER_SEPARATE);
ret = curl_easy_perform(curl);
curl_slist_free_all(list);
curl_easy_cleanup(curl);
}
}

AVAILABILITY

Added in curl 7.37.0

RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error
occurred, see libcurl-errors(3).