text: # -*- test-case-name: twisted.test.test_sslverify -*-
  # Copyright (c) Twisted Matrix Laboratories.
  # See LICENSE for details.
  
  """
  Shared interface to IDNA encoding and decoding, using the C{idna} PyPI package
  if available, otherwise the stdlib implementation.
  """
  
  def _idnaBytes(text):
      """
      Convert some text typed by a human into some ASCII bytes.
  
      This is provided to allow us to use the U{partially-broken IDNA
      implementation in the standard library <http://bugs.python.org/issue17305>}
      if the more-correct U{idna <https://pypi.python.org/pypi/idna>} package is
      not available; C{service_identity} is somewhat stricter about this.
  
      @param text: A domain name, hopefully.
      @type text: L{unicode}
  
      @return: The domain name's IDNA representation, encoded as bytes.
      @rtype: L{bytes}
      """
      try:
          import idna
      except ImportError:
          return text.encode("idna")
      else:
          return idna.encode(text)
  
  
  
  def _idnaText(octets):
      """
      Convert some IDNA-encoded octets into some human-readable text.
  
      Currently only used by the tests.
  
      @param octets: Some bytes representing a hostname.
      @type octets: L{bytes}
  
      @return: A human-readable domain name.
      @rtype: L{unicode}
      """
      try:
          import idna
      except ImportError:
          return octets.decode("idna")
      else:
          return idna.decode(octets)
  
  
  
  