CURLOPT_HTTPPROXYTUNNEL(3) Library Functions Manual
NAME
CURLOPT_HTTPPROXYTUNNEL - tunnel through HTTP proxy
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTPPROXYTUNNEL, long tunnel);
DESCRIPTION
Set the tunnel parameter to 1L to make libcurl tunnel all operations
through the HTTP proxy (s)). There is a big
difference between using a proxy and to tunnel through it.
Tunneling means that an HTTP CONNECT request is sent to the proxy,
asking it to connect to a remote host on a specific port number and
then the traffic is just passed through the proxy. Proxies tend to
white-list specific port numbers it allows CONNECT requests to and
often only port 80 and 443 are allowed.
To suppress proxy CONNECT response headers from user callbacks use
CURLOPT_SUPPRESS_CONNECT_HEADERS(3).
HTTP proxies can generally only speak HTTP (for obvious reasons), which
makes libcurl convert non-HTTP requests to HTTP when using an HTTP
proxy without this tunnel option set. For example, asking for an FTP
URL and specifying an HTTP proxy makes libcurl send an FTP URL in an
HTTP GET request to the proxy. By instead tunneling through the proxy,
you avoid that conversion (that rarely works through the proxy anyway).
DEFAULT
0
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com/file.txt");
curl_easy_setopt(curl, CURLOPT_PROXY, "http://127.0.0.1:80");
curl_easy_setopt(curl, CURLOPT_HTTPPROXYTUNNEL, 1L);
curl_easy_perform(curl);
}
}
AVAILABILITY
Added in curl 7.3
RETURN VALUE
Returns CURLE_OK
SEE ALSO
CURLOPT_PROXY(3), CURLOPT_PROXYPORT(3), CURLOPT_PROXYTYPE(3)
libcurl 2024-08-05 CURLOPT_HTTPPROXYTUNNEL(3)
curl 8.9.1 - Generated Mon Aug 12 16:45:14 CDT 2024