text: # -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from datetime import timedelta
  from flask import make_response, request, current_app
  from functools import update_wrapper
  
  
  def crossdomain(origin=None, methods=None, headers=None, expose_headers=None,
                  max_age=21600, attach_to_all=True,
                  automatic_options=True, credentials=False):
      """
      http://flask.pocoo.org/snippets/56/
      """
      if methods is not None:
          methods = ', '.join(sorted(x.upper() for x in methods))
      if headers is not None and not isinstance(headers, str):
          headers = ', '.join(x.upper() for x in headers)
      if expose_headers is not None and not isinstance(expose_headers, str):
          expose_headers = ', '.join(x.upper() for x in expose_headers)
      if not isinstance(origin, str):
          origin = ', '.join(origin)
      if isinstance(max_age, timedelta):
          max_age = max_age.total_seconds()
  
      def get_methods():
          if methods is not None:
              return methods
  
          options_resp = current_app.make_default_options_response()
          return options_resp.headers['allow']
  
      def decorator(f):
          def wrapped_function(*args, **kwargs):
              if automatic_options and request.method == 'OPTIONS':
                  resp = current_app.make_default_options_response()
              else:
                  resp = make_response(f(*args, **kwargs))
              if not attach_to_all and request.method != 'OPTIONS':
                  return resp
  
              h = resp.headers
  
              h['Access-Control-Allow-Origin'] = origin
              h['Access-Control-Allow-Methods'] = get_methods()
              h['Access-Control-Max-Age'] = str(max_age)
              if credentials:
                  h['Access-Control-Allow-Credentials'] = 'true'
              if headers is not None:
                  h['Access-Control-Allow-Headers'] = headers
              if expose_headers is not None:
                  h['Access-Control-Expose-Headers'] = expose_headers
              return resp
  
          f.provide_automatic_options = False
          return update_wrapper(wrapped_function, f)
      return decorator
  