Gem::Request.get_proxy_from_env

# File tmp/rubies/ruby-3.0.5/lib/rubygems/request.rb, line 161
def self.get_proxy_from_env(scheme = 'http')
  _scheme = scheme.downcase
  _SCHEME = scheme.upcase
  env_proxy = ENV["#{_scheme}_proxy"] || ENV["#{_SCHEME}_PROXY"]

  no_env_proxy = env_proxy.nil? || env_proxy.empty?

  if no_env_proxy
    return (_scheme == 'https' || _scheme == 'http') ?
      :no_proxy : get_proxy_from_env('http')
  end

  require "uri"
  uri = URI(Gem::UriFormatter.new(env_proxy).normalize)

  if uri and uri.user.nil? and uri.password.nil?
    user     = ENV["#{_scheme}_proxy_user"] || ENV["#{_SCHEME}_PROXY_USER"]
    password = ENV["#{_scheme}_proxy_pass"] || ENV["#{_SCHEME}_PROXY_PASS"]

    uri.user     = Gem::UriFormatter.new(user).escape
    uri.password = Gem::UriFormatter.new(password).escape
  end

  uri
end