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CURLOPT_PRE_PROXY(3) libcurl 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
default.
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
particular 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_PRE_PROXY, "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),
ibcurl 8.1.2 April 26, 2023 CURLOPT_PRE_PROXY(3)