# File lib/net/http/persistent.rb, line 730
  def proxy_from_env
    env_proxy = ENV['http_proxy'] || ENV['HTTP_PROXY']

    return nil if env_proxy.nil? or env_proxy.empty?

    uri = URI normalize_uri env_proxy

    unless uri.user or uri.password then
      uri.user     = escape ENV['http_proxy_user'] || ENV['HTTP_PROXY_USER']
      uri.password = escape ENV['http_proxy_pass'] || ENV['HTTP_PROXY_PASS']
    end

    uri
  end