proxyto use for the upcoming request. The parameter should be a 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
#CURLOPT_PROXYPORT. If not specified, libcurl will default to
using port 1080 for proxies.
The proxy string may be prefixed with [scheme]:// to specify which kind of proxy is used.
Without a scheme prefix,
#CURLOPT_PROXYTYPE can be used to specify
which kind of proxy the string identifies.
When you tell the library to use an HTTP proxy, libcurl will transparently
convert operations to HTTP even if you specify an FTP URL etc. This may have
an impact on what other features of the library you can use, such as
#CURLOPT_QUOTE and similar FTP specifics that don't work unless you
tunnel through the HTTP proxy. Such tunneling is activated with
Setting the proxy string to "" (an empty string) will explicitly disable the use of a proxy, even if there is an environment variable set for it.
A proxy host string can also include protocol scheme (http://) and embedded user + password.