authentic/src/authentic2/decorators.py

349 lines
11 KiB
Python

# authentic2 - versatile identity manager
# Copyright (C) 2010-2019 Entr'ouvert
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import base64
import pickle
import re
import time
from contextlib import contextmanager
from functools import wraps
from json import dumps as json_dumps
from django.core.cache import cache as django_cache
from django.core.exceptions import ValidationError
from django.http import Http404, HttpResponse, HttpResponseBadRequest, HttpResponseForbidden
from django.utils import six
from django.views.debug import technical_404_response
from . import app_settings, middleware
# XXX: import to_list for retrocompaibility
from .utils import to_iter, to_list # noqa: F401
class CacheUnusable(RuntimeError):
pass
def unless(test, message):
'''Decorator returning a 404 status code if some condition is not met'''
def decorator(func):
@wraps(func)
def f(request, *args, **kwargs):
if not test():
return technical_404_response(request, Http404(message))
return func(request, *args, **kwargs)
return f
return decorator
def setting_enabled(name, settings=app_settings):
'''Generate a decorator for enabling a view based on a setting'''
full_name = getattr(settings, 'prefix', '') + name
def test():
return getattr(settings, name, False)
return unless(test, 'please enable %s' % full_name)
def lasso_required():
def test():
try:
import lasso # noqa: F401
return True
except ImportError:
return False
return unless(test, 'please install lasso')
def required(wrapping_functions, patterns_rslt):
"""
Used to require 1..n decorators in any view returned by a url tree
Usage:
urlpatterns = required(func,patterns(...))
urlpatterns = required((func,func,func),patterns(...))
Note:
Use functools.partial to pass keyword params to the required
decorators. If you need to pass args you will have to write a
wrapper function.
Example:
from functools import partial
urlpatterns = required(
partial(login_required,login_url='/accounts/login/'),
patterns(...)
)
"""
if not hasattr(wrapping_functions, '__iter__'):
wrapping_functions = (wrapping_functions,)
return [_wrap_instance__resolve(wrapping_functions, instance) for instance in patterns_rslt]
def _wrap_instance__resolve(wrapping_functions, instance):
if not hasattr(instance, 'resolve'):
return instance
resolve = getattr(instance, 'resolve')
def _wrap_func_in_returned_resolver_match(*args, **kwargs):
rslt = resolve(*args, **kwargs)
if not hasattr(rslt, 'func'):
return rslt
f = getattr(rslt, 'func')
for _f in reversed(wrapping_functions):
# @decorate the function from inner to outter
f = _f(f)
setattr(rslt, 'func', f)
return rslt
setattr(instance, 'resolve', _wrap_func_in_returned_resolver_match)
return instance
class CacheDecoratorBase(object):
"""Base class to build cache decorators.
It helps for building keys from function arguments.
"""
def __new__(cls, *args, **kwargs):
if len(args) > 1:
raise TypeError(
'%s got unexpected arguments, only one argument must be given, the function to decorate'
% cls.__name__
)
if args:
# Case of a decorator used directly
return cls(**kwargs)(args[0])
return super(CacheDecoratorBase, cls).__new__(cls)
def __init__(self, timeout=None, hostname_vary=True, args=None, kwargs=None):
self.timeout = timeout
self.hostname_vary = hostname_vary
self.args = args
self.kwargs = kwargs
def set(self, key, value):
raise NotImplementedError
def get(self, key):
raise NotImplementedError
def clear(self):
raise NotImplementedError
def __call__(self, func):
@wraps(func)
def f(*args, **kwargs):
try:
if not app_settings.A2_CACHE_ENABLED:
raise CacheUnusable
now = time.time()
key = self.key(*args, **kwargs)
value, tstamp = self.get(key)
if tstamp is not None:
if self.timeout is None or tstamp + self.timeout > now:
return value
if hasattr(self, 'delete'):
self.delete(key, (key, tstamp))
value = func(*args, **kwargs)
self.set(key, (value, now))
return value
except CacheUnusable: # fallback when cache cannot be used
return func(*args, **kwargs)
f.cache = self
return f
def key(self, *args, **kwargs):
'''Transform arguments to string and build a key from it'''
parts = [str(id(self))] # add cache instance to the key
if self.hostname_vary:
request = middleware.StoreRequestMiddleware.get_request()
if request:
parts.append(request.get_host())
else:
# if we cannot determine the hostname it's better to ignore the
# cache
raise CacheUnusable
for i, arg in enumerate(args):
if self.args and i not in self.args:
continue
parts.append(six.text_type(arg))
for kw, arg in sorted(kwargs.items(), key=lambda x: x[0]):
if kw not in self.kwargs:
continue
parts.append(u'%s-%s' % (six.text_type(kw), six.text_type(arg)))
return u'|'.join(parts)
class SimpleDictionnaryCacheMixin(object):
"""Default implementations of set, get and delete for a cache implemented
using a dictionary. The dictionnary must be returned by a property named
'cache'.
"""
def set(self, key, value):
self.cache[key] = value
def get(self, key):
return self.cache.get(key, (None, None))
def delete(self, key, value):
if key in self.cache and self.cache[key] == value:
del self.cache[key]
def clear(self):
self.cache.clear()
class GlobalCache(SimpleDictionnaryCacheMixin, CacheDecoratorBase):
def __init__(self, *args, **kwargs):
self.cache = {}
super(GlobalCache, self).__init__(*args, **kwargs)
class RequestCache(SimpleDictionnaryCacheMixin, CacheDecoratorBase):
@property
def cache(self):
request = middleware.StoreRequestMiddleware.get_request()
if not request:
return {}
# create a cache dictionary on the request
return request.__dict__.setdefault(self.__class__.__name__, {})
class DjangoCache(SimpleDictionnaryCacheMixin, CacheDecoratorBase):
@property
def cache(self):
return django_cache
def set(self, key, value):
self.cache.set(key, value, timeout=self.timeout)
def delete(self, key, value):
if self.get(key) == value:
self.delete(key)
class PickleCacheMixin(object):
def set(self, key, value):
value, tstamp = value
value = base64.b64encode(pickle.dumps(value)).decode('ascii')
super(PickleCacheMixin, self).set(key, (value, tstamp))
def get(self, key):
value = super(PickleCacheMixin, self).get(key)
if value[0] is not None:
value, tstamp = value
try:
value = base64.b64decode(value.encode('ascii'))
except ValueError:
pass
value = (pickle.loads(value), tstamp)
return value
class SessionCache(PickleCacheMixin, SimpleDictionnaryCacheMixin, CacheDecoratorBase):
@property
def cache(self):
request = middleware.StoreRequestMiddleware.get_request()
if not request:
return {}
# create a cache dictionary on the request
return request.session.setdefault(self.__class__.__name__, {})
def set(self, key, value):
request = middleware.StoreRequestMiddleware.get_request()
if request:
request.session.modified = True
return super(SessionCache, self).set(key, value)
def clear(self):
request = middleware.StoreRequestMiddleware.get_request()
if request:
request.session.modified = True
return super(SessionCache, self).clear()
@contextmanager
def errorcollector(error_dict):
try:
yield
except ValidationError as e:
e.update_error_dict(error_dict)
def json(func):
'''Convert view to a JSON or JSON web-service supporting CORS'''
from . import cors
@wraps(func)
def f(request, *args, **kwargs):
jsonp = False
# Differentiate JSONP from AJAX
if request.method == 'GET':
for variable in ('jsonpCallback', 'callback'):
if variable in request.GET:
identifier = request.GET[variable]
if not re.match(r'^[$a-zA-Z_][0-9a-zA-Z_$]*$', identifier):
return HttpResponseBadRequest(
'invalid JSONP callback name', content_type='text/plain'
)
jsonp = True
break
# 1. check origin
if jsonp:
origin = request.META.get('HTTP_REFERER')
if not origin:
# JSONP is unusable for people without referers
return HttpResponseForbidden('missing referrer', content_type='text/plain')
origin = cors.make_origin(origin)
else:
origin = request.META.get('HTTP_ORIGIN')
if origin:
if not cors.check_origin(request, origin):
return HttpResponseForbidden('bad origin', content_type='text/plain')
# 2. build response
result = func(request, *args, **kwargs)
json_str = json_dumps(result)
if jsonp:
response = HttpResponse(content_type='application/javascript')
json_str = '%s(%s);' % (identifier, json_str)
else:
response = HttpResponse(content_type='application/json')
response['Access-Control-Allow-Origin'] = origin
response['Access-Control-Allow-Credentials'] = 'true'
response['Access-Control-Allow-Headers'] = 'x-requested-with'
response.write(json_str)
return response
return f