Class: URI::Generic (Ruby 1.9.3)returns a proxy URI. The proxy URI is obtained from environment variables such as http_proxy, ftp_proxy, no_proxy, etc. If there is no proper proxy, nil is returned. Note that capitalized variables (HTTP_PROXY, FTP_PROXY, NO_PROXY, etc.) are examined too. But http_proxy and HTTP_PROXY is treated specially under CGI environment. It's because HTTP_PROXY may be set by Proxy: header. So HTTP_PROXY is
