CURLOPT_PROXY_TRANSFER_MODE(3) Library Functions Manual CURLOPT_PROXY_TRANSFER_MODE(3)

CURLOPT_PROXY_TRANSFER_MODE - append FTP transfer mode to URL for proxy

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_TRANSFER_MODE,
                          long enabled);

Pass a long. If the value is set to 1 (one), it tells libcurl to set the transfer mode (binary or ASCII) for FTP transfers done via an HTTP proxy, by appending ;type=a or ;type=i to the URL. Without this setting, or it being set to 0 (zero, the default), CURLOPT_TRANSFERTEXT(3) has no effect when doing FTP via a proxy. Beware that not all proxies support this feature.

0, disabled

All

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL,
                     "ftp://example.com/old-server/file.txt");
    curl_easy_setopt(curl, CURLOPT_PROXY, "http://localhost:80");
    curl_easy_setopt(curl, CURLOPT_PROXY_TRANSFER_MODE, 1L);
    curl_easy_setopt(curl, CURLOPT_TRANSFERTEXT, 1L);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

Added in 7.18.0

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if the enabled value is not supported.

CURLOPT_CRLF(3), CURLOPT_HTTPPROXYTUNNEL(3), CURLOPT_PROXY(3), CURLOPT_TRANSFERTEXT(3)

April 26 2024 libcurl