class Object
  def pose_as(klass)
    namespace = klass.to_s.split("::")
    klass =  namespace.pop

    if namespace.any?
      eval <<-EOT
      module ::#{namespace.join("::")}
        send(:remove_const, :"#{klass}")
        #{klass} = #{self}
      end
      EOT
    else
      eval <<-EOT
        Object.send(:remove_const, :"#{klass}")
        #{klass} = #{self}
      EOT
    end
  end
end

require 'net/http'
class ProxiedHttp < Net::HTTP
  def self.Proxy(p_addr, p_port = nil, p_user = nil, p_pass = nil)

    if env_proxy = (ENV["HTTP_PROXY"] || ENV["http_proxy"])
      uri = URI.parse(env_proxy)
      p_addr = uri.host
      p_port = uri.port
      if p_user = (ENV["HTTP_PROXY_USER"] || ENV["http_proxy_user"])
        p_pass = (ENV["HTTP_PROXY_PASSWORD"] || ENV["http_proxy_password"])
      end
    end

    super(p_addr, p_port, p_user, p_pass)
  end
end

ProxiedHttp.pose_as(Net::HTTP)

from now on Net::HTTP transparently honors ENV["HTTP_PROXY"]