Configure a Forward Proxy with PhpXmlRpc Client.setProxy

PhpXmlRpc's namespaced client exposes setProxy for a forward-proxy route:

use PhpXmlRpc\Client;

$client = new Client('https://rpc.example/service');
$client->setProxy('proxy.example', 8080);

The constructor selects the XML-RPC service; setProxy takes the intermediary's host and port. An HTTP address from the HTTP proxy list can fill them for a permitted public XML-RPC endpoint route that needs no proxy account. It also accepts proxy username, password, and authentication-type arguments when the selected transport supports the required scheme.

Send the application's XML-RPC messages through this configured instance and handle faults through the library's normal API. Preserve the transport's HTTPS certificate verification.

For a framework-owned client

CodeIgniter 3's built-in XML-RPC library is a different class. Its server method sets the destination; the PhpXmlRpc example does not establish that $this->xmlrpc exposes setProxy.

Identify the instantiated class and transport, then use that client's proxy interface while retaining the framework's message construction where possible.