190 lines
6.5 KiB
Python
190 lines
6.5 KiB
Python
# Copyright 2015 Google Inc. All rights reserved.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
"""This module contains the views used by the OAuth2 flows.
|
|
|
|
Their are two views used by the OAuth2 flow, the authorize and the callback
|
|
view. The authorize view kicks off the three-legged OAuth flow, and the
|
|
callback view validates the flow and if successful stores the credentials
|
|
in the configured storage."""
|
|
|
|
import hashlib
|
|
import json
|
|
import os
|
|
import pickle
|
|
|
|
from django import http
|
|
from django import shortcuts
|
|
from django.conf import settings
|
|
from django.core import urlresolvers
|
|
from django.shortcuts import redirect
|
|
from six.moves.urllib import parse
|
|
|
|
from oauth2client import client
|
|
from oauth2client.contrib import django_util
|
|
from oauth2client.contrib.django_util import get_storage
|
|
from oauth2client.contrib.django_util import signals
|
|
|
|
_CSRF_KEY = 'google_oauth2_csrf_token'
|
|
_FLOW_KEY = 'google_oauth2_flow_{0}'
|
|
|
|
|
|
def _make_flow(request, scopes, return_url=None):
|
|
"""Creates a Web Server Flow
|
|
|
|
Args:
|
|
request: A Django request object.
|
|
scopes: the request oauth2 scopes.
|
|
return_url: The URL to return to after the flow is complete. Defaults
|
|
to the path of the current request.
|
|
|
|
Returns:
|
|
An OAuth2 flow object that has been stored in the session.
|
|
"""
|
|
# Generate a CSRF token to prevent malicious requests.
|
|
csrf_token = hashlib.sha256(os.urandom(1024)).hexdigest()
|
|
|
|
request.session[_CSRF_KEY] = csrf_token
|
|
|
|
state = json.dumps({
|
|
'csrf_token': csrf_token,
|
|
'return_url': return_url,
|
|
})
|
|
|
|
flow = client.OAuth2WebServerFlow(
|
|
client_id=django_util.oauth2_settings.client_id,
|
|
client_secret=django_util.oauth2_settings.client_secret,
|
|
scope=scopes,
|
|
state=state,
|
|
redirect_uri=request.build_absolute_uri(
|
|
urlresolvers.reverse("google_oauth:callback")))
|
|
|
|
flow_key = _FLOW_KEY.format(csrf_token)
|
|
request.session[flow_key] = pickle.dumps(flow)
|
|
return flow
|
|
|
|
|
|
def _get_flow_for_token(csrf_token, request):
|
|
""" Looks up the flow in session to recover information about requested
|
|
scopes.
|
|
|
|
Args:
|
|
csrf_token: The token passed in the callback request that should
|
|
match the one previously generated and stored in the request on the
|
|
initial authorization view.
|
|
|
|
Returns:
|
|
The OAuth2 Flow object associated with this flow based on the
|
|
CSRF token.
|
|
"""
|
|
flow_pickle = request.session.get(_FLOW_KEY.format(csrf_token), None)
|
|
return None if flow_pickle is None else pickle.loads(flow_pickle)
|
|
|
|
|
|
def oauth2_callback(request):
|
|
""" View that handles the user's return from OAuth2 provider.
|
|
|
|
This view verifies the CSRF state and OAuth authorization code, and on
|
|
success stores the credentials obtained in the storage provider,
|
|
and redirects to the return_url specified in the authorize view and
|
|
stored in the session.
|
|
|
|
Args:
|
|
request: Django request.
|
|
|
|
Returns:
|
|
A redirect response back to the return_url.
|
|
"""
|
|
if 'error' in request.GET:
|
|
reason = request.GET.get(
|
|
'error_description', request.GET.get('error', ''))
|
|
return http.HttpResponseBadRequest(
|
|
'Authorization failed {0}'.format(reason))
|
|
|
|
try:
|
|
encoded_state = request.GET['state']
|
|
code = request.GET['code']
|
|
except KeyError:
|
|
return http.HttpResponseBadRequest(
|
|
'Request missing state or authorization code')
|
|
|
|
try:
|
|
server_csrf = request.session[_CSRF_KEY]
|
|
except KeyError:
|
|
return http.HttpResponseBadRequest(
|
|
'No existing session for this flow.')
|
|
|
|
try:
|
|
state = json.loads(encoded_state)
|
|
client_csrf = state['csrf_token']
|
|
return_url = state['return_url']
|
|
except (ValueError, KeyError):
|
|
return http.HttpResponseBadRequest('Invalid state parameter.')
|
|
|
|
if client_csrf != server_csrf:
|
|
return http.HttpResponseBadRequest('Invalid CSRF token.')
|
|
|
|
flow = _get_flow_for_token(client_csrf, request)
|
|
|
|
if not flow:
|
|
return http.HttpResponseBadRequest('Missing Oauth2 flow.')
|
|
|
|
try:
|
|
credentials = flow.step2_exchange(code)
|
|
except client.FlowExchangeError as exchange_error:
|
|
return http.HttpResponseBadRequest(
|
|
'An error has occurred: {0}'.format(exchange_error))
|
|
|
|
get_storage(request).put(credentials)
|
|
|
|
signals.oauth2_authorized.send(sender=signals.oauth2_authorized,
|
|
request=request, credentials=credentials)
|
|
|
|
return shortcuts.redirect(return_url)
|
|
|
|
|
|
def oauth2_authorize(request):
|
|
""" View to start the OAuth2 Authorization flow.
|
|
|
|
This view starts the OAuth2 authorization flow. If scopes is passed in
|
|
as a GET URL parameter, it will authorize those scopes, otherwise the
|
|
default scopes specified in settings. The return_url can also be
|
|
specified as a GET parameter, otherwise the referer header will be
|
|
checked, and if that isn't found it will return to the root path.
|
|
|
|
Args:
|
|
request: The Django request object.
|
|
|
|
Returns:
|
|
A redirect to Google OAuth2 Authorization.
|
|
"""
|
|
return_url = request.GET.get('return_url', None)
|
|
|
|
# Model storage (but not session storage) requires a logged in user
|
|
if django_util.oauth2_settings.storage_model:
|
|
if not request.user.is_authenticated():
|
|
return redirect('{0}?next={1}'.format(
|
|
settings.LOGIN_URL, parse.quote(request.get_full_path())))
|
|
# This checks for the case where we ended up here because of a logged
|
|
# out user but we had credentials for it in the first place
|
|
elif get_storage(request).get() is not None:
|
|
return redirect(return_url)
|
|
|
|
scopes = request.GET.getlist('scopes', django_util.oauth2_settings.scopes)
|
|
|
|
if not return_url:
|
|
return_url = request.META.get('HTTP_REFERER', '/')
|
|
flow = _make_flow(request=request, scopes=scopes, return_url=return_url)
|
|
auth_url = flow.step1_get_authorize_url()
|
|
return shortcuts.redirect(auth_url)
|