在PHP中自动检测服务器的代理设置

I have a PHP script which is running on a windows server. The script creates a SOAP client object which can be given proxy_host and a proxy_port. Rather than hardcoding these values or making them a config option, I'd like the PHP script to automatically detect the local server's proxy settings so that if they change or if the script is run on a different server, it will just work. Does anybody know how to do this in PHP?I have a PHP script which is running on a windo