# -*- coding: utf-8 -*-

class Middleware(object):

""" middleware is the object to store request/response handlers

>>> middleware = Middleware()

Add a request handler to prepare the request

>>> @middleware.request

... def prepare(req):

... req['Region'] = 'cn-bj2'

... return req

Add a response handler to log the response detail

>>> @middleware.response

... def logged(resp):

... print(resp)

... return resp

>>> len(middleware.request_handlers), len(middleware.response_handlers)

(1, 1)

"""

def __init__(self):

self.request_handlers = []

self.response_handlers = []

def request(self, handler, index=-1):

""" request is the request handler register to add request handler.

:param handler: request handler function, receive request object

and return a new request

:param int index: the position of request in the handler list,

default is append it to end

:return:

"""

self.request_handlers.insert(index, handler)

return handler

def response(self, handler, index=-1):

""" response is the response handler register to add response handler.

:param handler: response handler function, receive response object

and return a new response

:param int index: the position of response in the handler list,

default is append it to end

:return:

"""

self.response_handlers.insert(index, handler)

return handler