# -*- coding: utf-8 -*-
# Flask-FAS-OpenID - A Flask extension for authorizing users with FAS-OpenID
#
# Primary maintainer: Patrick Uiterwijk <puiterwijk@fedoraproject.org>
#
# Copyright (c) 2013, Patrick Uiterwijk
# This file is part of python-fedora
#
# python-fedora is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# python-fedora is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with python-fedora; if not, see <http://www.gnu.org/licenses/>
'''
FAS-OpenID authentication plugin for the flask web framework
.. moduleauthor:: Patrick Uiterwijk <puiterwijk@fedoraproject.org>
..versionadded:: 0.3.33
'''
from functools import wraps
from bunch import Bunch
import flask
try:
from flask import _app_ctx_stack as stack
except ImportError:
from flask import _request_ctx_stack as stack
import openid
from openid.consumer import consumer
from openid.fetchers import setDefaultFetcher, Urllib2Fetcher
from openid.extensions import pape, sreg
from openid_cla import cla
from openid_teams import teams
from fedora import __version__
class FASJSONEncoder(flask.json.JSONEncoder):
""" Dedicated JSON encoder for the FAS openid information. """
def default(self, o):
"""Implement this method in a subclass such that it returns a
serializable object for ``o``, or calls the base implementation (to
raise a ``TypeError``).
For example, to support arbitrary iterators, you could implement
default like this::
def default(self, o):
try:
iterable = iter(o)
except TypeError:
pass
else:
return list(iterable)
return JSONEncoder.default(self, o)
"""
if isinstance(o, (set, frozenset)):
return list(o)
return flask.json.JSONEncoder.default(self, o)
class FAS(object):
def __init__(self, app=None):
self.postlogin_func = None
self.app = app
if self.app is not None:
self._init_app(app)
# json_encoder is only available from flask 0.10
version = flask.__version__.split('.')
assume_recent = False
try:
major = int(version[0])
minor = int(version[1])
except ValueError:
# We'll assume we're using a recent enough flask as the packages
# of old versions used sane version numbers.
assume_recent = True
if assume_recent or (major >= 0 and minor >= 10):
self.app.json_encoder = FASJSONEncoder
def _init_app(self, app):
app.config.setdefault('FAS_OPENID_ENDPOINT',
'http://id.fedoraproject.org/')
app.config.setdefault('FAS_OPENID_CHECK_CERT', True)
if not self.app.config['FAS_OPENID_CHECK_CERT']:
setDefaultFetcher(Urllib2Fetcher())
@app.route('/_flask_fas_openid_handler/', methods=['GET', 'POST'])
def flask_fas_openid_handler():
return self._handle_openid_request()
app.before_request(self._check_session)
def postlogin(self, f):
"""Marks a function as post login handler. This decorator calls your
function after the login has been performed.
"""
self.postlogin_func = f
return f
def _handle_openid_request(self):
return_url = flask.session.get('FLASK_FAS_OPENID_RETURN_URL', None)
cancel_url = flask.session.get('FLASK_FAS_OPENID_CANCEL_URL', None)
base_url = self.normalize_url(flask.request.base_url)
oidconsumer = consumer.Consumer(flask.session, None)
info = oidconsumer.complete(flask.request.values, base_url)
display_identifier = info.getDisplayIdentifier()
if info.status == consumer.FAILURE and display_identifier:
return 'FAILURE. display_identifier: %s' % display_identifier
elif info.status == consumer.CANCEL:
if cancel_url:
return flask.redirect(cancel_url)
return 'OpenID request was cancelled'
elif info.status == consumer.SUCCESS:
sreg_resp = sreg.SRegResponse.fromSuccessResponse(info)
pape_resp = pape.Response.fromSuccessResponse(info)
teams_resp = teams.TeamsResponse.fromSuccessResponse(info)
cla_resp = cla.CLAResponse.fromSuccessResponse(info)
user = {'fullname': '', 'username': '', 'email': '',
'timezone': '', 'cla_done': False, 'groups': []}
if not sreg_resp:
# If we have no basic info, be gone with them!
return flask.redirect(cancel_url)
user['username'] = sreg_resp.get('nickname')
user['fullname'] = sreg_resp.get('fullname')
user['email'] = sreg_resp.get('email')
user['timezone'] = sreg_resp.get('timezone')
if cla_resp:
user['cla_done'] = cla.CLA_URI_FEDORA_DONE in cla_resp.clas
if teams_resp:
# The groups do not contain the cla_ groups
user['groups'] = frozenset(teams_resp.teams)
flask.session['FLASK_FAS_OPENID_USER'] = user
flask.session.modified = True
if self.postlogin_func is not None:
self._check_session()
return self.postlogin_func(return_url)
else:
return flask.redirect(return_url)
else:
return 'Strange state: %s' % info.status
def _check_session(self):
if not 'FLASK_FAS_OPENID_USER' in flask.session \
or flask.session['FLASK_FAS_OPENID_USER'] is None:
flask.g.fas_user = None
else:
user = flask.session['FLASK_FAS_OPENID_USER']
# Add approved_memberships to provide backwards compatibility
# New applications should only use g.fas_user.groups
user['approved_memberships'] = []
for group in user['groups']:
membership = dict()
membership['name'] = group
user['approved_memberships'].append(Bunch.fromDict(membership))
flask.g.fas_user = Bunch.fromDict(user)
flask.g.fas_user.groups = frozenset(flask.g.fas_user.groups)
flask.g.fas_session_id = 0
def login(self, username=None, password=None, return_url=None,
cancel_url=None, groups=['_FAS_ALL_GROUPS_']):
"""Tries to log in a user.
Sets the user information on :attr:`flask.g.fas_user`.
Will set 0 to :attr:`flask.g.fas_session_id, for compatibility
with flask_fas.
:kwarg username: Not used, but accepted for compatibility with the
flask_fas module
:kwarg password: Not used, but accepted for compatibility with the
flask_fas module
:kwarg return_url: The URL to forward the user to after login
:kwarg groups: A string or a list of group the user should belong
to to be authentified.
:returns: True if the user was succesfully authenticated.
:raises: Might raise an redirect to the OpenID endpoint
"""
if return_url is None and return_func is None:
return_url = flask.request.args.get('next', flask.request.url)
session = {}
oidconsumer = consumer.Consumer(session, None)
try:
request = oidconsumer.begin(self.app.config['FAS_OPENID_ENDPOINT'])
except consumer.DiscoveryFailure, exc:
# VERY strange, as this means it could not discover an OpenID
# endpoint at FAS_OPENID_ENDPOINT
return 'discoveryfailure'
if request is None:
# Also very strange, as this means the discovered OpenID
# endpoint is no OpenID endpoint
return 'no-request'
if isinstance(groups, basestring):
groups = [groups]
request.addExtension(sreg.SRegRequest(
required=['nickname', 'fullname', 'email', 'timezone']))
request.addExtension(pape.Request([]))
request.addExtension(teams.TeamsRequest(requested=groups))
request.addExtension(cla.CLARequest(
requested=[cla.CLA_URI_FEDORA_DONE]))
trust_root = self.normalize_url(flask.request.url_root)
return_to = trust_root + '_flask_fas_openid_handler/'
flask.session['FLASK_FAS_OPENID_RETURN_URL'] = return_url
flask.session['FLASK_FAS_OPENID_CANCEL_URL'] = cancel_url
if request.shouldSendRedirect():
redirect_url = request.redirectURL(
trust_root, return_to, False)
return flask.redirect(redirect_url)
else:
return request.htmlMarkup(
trust_root, return_to,
form_tag_attrs={'id': 'openid_message'}, immediate=False)
def logout(self):
'''Logout the user associated with this session
'''
flask.session['FLASK_FAS_OPENID_USER'] = None
flask.g.fas_session_id = None
flask.g.fas_user = None
flask.session.modified = True
def normalize_url(self, url):
''' Replace the scheme prefix of a url with our preferred scheme.
'''
scheme = self.app.config['PREFERRED_URL_SCHEME']
scheme_index = url.index('://')
return scheme + url[scheme_index:]
# This is a decorator we can use with any HTTP method (except login, obviously)
# to require a login.
# If the user is not logged in, it will redirect them to the login form.
# http://flask.pocoo.org/docs/patterns/viewdecorators/#login-required-decorator
def fas_login_required(function):
""" Flask decorator to ensure that the user is logged in against FAS.
To use this decorator you need to have a function named 'auth_login'.
Without that function the redirect if the user is not logged in will not
work.
"""
@wraps(function)
def decorated_function(*args, **kwargs):
if flask.g.fas_user is None:
return flask.redirect(flask.url_for('auth_login',
next=flask.request.url))
return function(*args, **kwargs)
return decorated_function
def cla_plus_one_required(function):
""" Flask decorator to retrict access to CLA+1.
To use this decorator you need to have a function named 'auth_login'.
Without that function the redirect if the user is not logged in will not
work.
"""
@wraps(function)
def decorated_function(*args, **kwargs):
if flask.g.fas_user is None or not flask.g.fas_user.cla_done \
or len(flask.g.fas_user.groups) < 1:
# FAS-OpenID does not return cla_ groups
return flask.redirect(flask.url_for('auth_login',
next=flask.request.url))
else:
return function(*args, **kwargs)
return decorated_function