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 (set with
       CURLOPT_PROXY(3)). 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

       All network 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

       Always

RETURN VALUE

       Returns CURLE_OK

SEE ALSO

       CURLOPT_PROXY(3), CURLOPT_PROXYTYPE(3), CURLOPT_PROXYPORT(3)