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# Copyright 2017 Canonical Ltd.
# Licensed under the LGPLv3, see LICENCE file for details.
import base64
import json
import requests
from six.moves.http_cookies import SimpleCookie
from six.moves.http_cookiejar import Cookie
from six.moves.urllib.parse import urljoin
from six.moves.urllib.parse import urlparse
from pymacaroons import Macaroon
from pymacaroons.serializers.json_serializer import JsonSerializer
from macaroonbakery.bakery import discharge_all
from macaroonbakery import utils
ERR_INTERACTION_REQUIRED = 'interaction required'
ERR_DISCHARGE_REQUIRED = 'macaroon discharge required'
TIME_OUT = 30
MAX_DISCHARGE_RETRIES = 3
class BakeryAuth:
''' BakeryAuth holds the context for making HTTP requests with macaroons.
This will automatically acquire and discharge macaroons around the
requests framework.
Usage:
from macaroonbakery import httpbakery
jar = requests.cookies.RequestsCookieJar()
resp = requests.get('some protected url',
cookies=jar,
auth=httpbakery.BakeryAuth(cookies=jar))
resp.raise_for_status()
'''
def __init__(self, visit_page=None, key=None,
cookies=requests.cookies.RequestsCookieJar()):
'''
@param visit_page function called when the discharge process requires
further interaction taking a visit_url string as parameter.
@param key holds the client's private nacl key. If set, the client
will try to discharge third party caveats with the special location
"local" by using this key.
@param cookies storage for the cookies {CookieJar}. It should be the
same than in the requests cookies
'''
if visit_page is None:
visit_page = utils.visit_page_with_browser
if 'agent-login' in cookies.keys():
self._visit_page = _visit_page_for_agent(cookies, key)
else:
self._visit_page = visit_page
self._jar = cookies
self._key = key
def __call__(self, req):
req.headers['Bakery-Protocol-Version'] = '1'
hook = _prepare_discharge_hook(req.copy(), self._key, self._jar,
self._visit_page)
req.register_hook(event='response', hook=hook)
return req
def _prepare_discharge_hook(req, key, jar, visit_page):
''' Return the hook function (called when the response is received.)
This allows us to intercept the response and do any necessary
macaroon discharge before returning.
'''
class Retry:
# Define a local class so that we can use its class variable as
# mutable state accessed by the closures below.
count = 0
def hook(response, *args, **kwargs):
''' Requests hooks system, this is the hook for the response.
'''
status_401 = (response.status_code == 401
and response.headers.get('WWW-Authenticate') ==
'Macaroon')
if not status_401 and response.status_code != 407:
return response
if response.headers.get('Content-Type') != 'application/json':
return response
try:
error = response.json()
except:
raise BakeryException(
'unable to read discharge error response')
if error.get('Code') != ERR_DISCHARGE_REQUIRED:
return response
Retry.count += 1
if Retry.count > MAX_DISCHARGE_RETRIES:
raise BakeryException('too many discharges')
info = error.get('Info')
if not isinstance(info, dict):
raise BakeryException(
'unable to read info in discharge error response')
serialized_macaroon = info.get('Macaroon')
if not isinstance(serialized_macaroon, dict):
raise BakeryException(
'unable to read macaroon in discharge error response')
macaroon = utils.deserialize(serialized_macaroon)
discharges = discharge_all(macaroon, visit_page, jar, key)
encoded_discharges = map(utils.serialize_macaroon_string, discharges)
macaroons = '[' + ','.join(encoded_discharges) + ']'
all_macaroons = base64.urlsafe_b64encode(
macaroons.encode('utf-8')).decode('ascii')
full_path = urljoin(response.url,
info['MacaroonPath'])
parsed_url = urlparse(full_path)
if info and info.get('CookieNameSuffix'):
name = 'macaroon-' + info['CookieNameSuffix']
else:
name = 'macaroon-' + discharges[0].signature
cookie = Cookie(
version=0,
name=name,
value=all_macaroons,
port=None,
port_specified=False,
domain=parsed_url[1],
domain_specified=True,
domain_initial_dot=False,
path=parsed_url[2],
path_specified=True,
secure=False,
expires=None,
discard=False,
comment=None,
comment_url=None,
rest=None,
rfc2109=False)
jar.set_cookie(cookie)
# Replace the private _cookies from req as it is a copy of
# the original cookie jar passed into the requests method and we need
# to set the cookie for this request.
req._cookies = jar
req.headers.pop('Cookie', None)
req.prepare_cookies(req._cookies)
req.headers['Bakery-Protocol-Version'] = '1'
with requests.Session() as s:
return s.send(req)
return hook
class BakeryException(requests.RequestException):
''' Bakery exception '''
def _visit_page_for_agent(cookies, key):
def visit_page_for_agent(visit_url):
resp = requests.get(visit_url, cookies=cookies,
auth=BakeryAuth(cookies=cookies, key=key))
resp.raise_for_status()
return visit_page_for_agent
def extract_macaroons(headers):
''' Returns an array of any macaroons found in the given slice of cookies.
@param headers: dict of headers
@return: An array of array of mpy macaroons
'''
cookie_string = "\n".join(headers.get_all('Cookie', failobj=[]))
cs = SimpleCookie()
cs.load(cookie_string)
mss = []
for c in cs:
if not c.startswith('macaroon-'):
continue
data = base64.b64decode(cs[c].value)
data_as_objs = json.loads(data.decode('utf-8'))
ms = [Macaroon.deserialize(json.dumps(x), serializer=JsonSerializer())
for x in data_as_objs]
mss.append(ms)
return mss
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