1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Title: CURLOPT_PRE_PROXY 5Section: 3 6Source: libcurl 7See-also: 8 - CURLOPT_HTTPPROXYTUNNEL (3) 9 - CURLOPT_PROXY (3) 10Protocol: 11 - All 12--- 13 14# NAME 15 16CURLOPT_PRE_PROXY - pre-proxy host to use 17 18# SYNOPSIS 19 20~~~c 21#include <curl/curl.h> 22 23CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PRE_PROXY, char *preproxy); 24~~~ 25 26# DESCRIPTION 27 28Set the *preproxy* to use for the upcoming request. The parameter should be a 29char * to a null-terminated string holding the hostname or dotted numerical IP 30address. A numerical IPv6 address must be written within [brackets]. 31 32To specify port number in this string, append :[port] to the end of the host 33name. The proxy's port number may optionally be specified with the separate 34option CURLOPT_PROXYPORT(3). If not specified, libcurl defaults to using 35port 1080 for proxies. 36 37A pre proxy is a SOCKS proxy that curl connects to before it connects to the 38HTTP(S) proxy specified in the CURLOPT_PROXY(3) option. The pre proxy 39can only be a SOCKS proxy. 40 41The pre proxy string should be prefixed with [scheme]:// to specify which kind 42of socks is used. Use socks4://, socks4a://, socks5:// or socks5h:// (the last 43one to enable socks5 and asking the proxy to do the resolving, also known as 44*CURLPROXY_SOCKS5_HOSTNAME* type) to request the specific SOCKS version to 45be used. Otherwise SOCKS4 is used as default. 46 47Setting the pre proxy string to "" (an empty string) explicitly disables the 48use of a pre proxy. 49 50The application does not have to keep the string around after setting this 51option. 52 53# DEFAULT 54 55Default is NULL, meaning no pre proxy is used. 56 57When you set a hostname to use, do not assume that there is any particular 58single port number used widely for proxies. Specify it! 59 60# EXAMPLE 61 62~~~c 63int main(void) 64{ 65 CURL *curl = curl_easy_init(); 66 if(curl) { 67 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/file.txt"); 68 curl_easy_setopt(curl, CURLOPT_PRE_PROXY, "socks4://socks-proxy:1080"); 69 curl_easy_setopt(curl, CURLOPT_PROXY, "http://proxy:80"); 70 curl_easy_perform(curl); 71 } 72} 73~~~ 74 75# AVAILABILITY 76 77Added in 7.52.0 78 79# RETURN VALUE 80 81Returns CURLE_OK if proxies are supported, CURLE_UNKNOWN_OPTION if not, or 82CURLE_OUT_OF_MEMORY if there was insufficient heap space. 83
