CURLOPT_PRE_PROXY(3) curl_easy_setopt options CURLOPT_PRE_PROXY(3)
NAME
CURLOPT_PRE_PROXY - pre-proxy host to use
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PRE_PROXY, char *preproxy);
DESCRIPTION
Set the preproxy to use for the upcoming request. The parameter should
be a char * to a null-terminated string holding the host name or dotted
numerical IP address. A numerical IPv6 address must be written within
[brackets].
To specify port number in this string, append :[port] to the end of the
host name. The proxy's port number may optionally be specified with the
separate option CURLOPT_PROXYPORT(3). If not specified, libcurl will
default to using port 1080 for proxies.
A pre proxy is a SOCKS proxy that curl connects to before it connects
to the HTTP(S) proxy specified in the CURLOPT_PROXY option. The pre
proxy can only be a SOCKS proxy.
The pre proxy string should be prefixed with [scheme]:// to specify
which kind of socks is used. Use socks4://, socks4a://, socks5:// or
socks5h:// (the last one to enable socks5 and asking the proxy to do
the resolving, also known as CURLPROXY_SOCKS5_HOSTNAME type) to request
the specific SOCKS version to be used. Otherwise SOCKS4 is used as de-
fault.
Setting the pre proxy string to "" (an empty string) will explicitly
disable the use of a pre proxy.
The application does not have to keep the string around after setting
this option.
DEFAULT
Default is NULL, meaning no pre proxy is used.
When you set a host name to use, do not assume that there's any partic-
ular single port number used widely for proxies. Specify it!
PROTOCOLS
All except file://. Note that some protocols do not work well over
proxy.
EXAMPLE
CURL *curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/file.txt");
curl_easy_setopt(curl, CURLOPT_PREPROXY, "socks4://socks-proxy:1080");
curl_easy_setopt(curl, CURLOPT_PROXY, "http://proxy:80");
curl_easy_perform(curl);
}
AVAILABILITY
Added in 7.52.0
RETURN VALUE
Returns CURLE_OK if proxies are supported, CURLE_UNKNOWN_OPTION if not,
or CURLE_OUT_OF_MEMORY if there was insufficient heap space.
SEE ALSO
CURLOPT_PROXY(3), CURLOPT_HTTPPROXYTUNNEL(3),
libcurl 7.81.0 November 26, 2021 CURLOPT_PRE_PROXY(3)
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