paula.authutil/trunk/src/paula/authutil/utils.py

   1 # Copyright (c) 2008 by Florian Friesdorf
   2 #
   3 # GNU Affero General Public License (AGPL)
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU Affero General Public License as
   7 # published by the Free Software Foundation; either version 3 of the
   8 # License, or (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13 # GNU Affero General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU Affero General Public
  16 # License along with this program.  If not, see
  17 # <http://www.gnu.org/licenses/>.
  18 """
  19 """
  20 __author__ = "Florian Friesdorf <flo@chaoflow.net>"
  21 __docformat__ = "plaintext"
  22
  23 from BTrees import OOBTree
  24 from persistent import Persistent
  25
  26 from zope.app.container.contained import Contained
  27
  28 from zope.component import queryUtility
  29 from zope.component.interfaces import IFactory
  30
  31 from zope.interface import implements
  32
  33 from paula.authentication.interfaces import IAuthProvider
  34
  35 from paula.authutil.interfaces import IRWAuthProviders
  36 from paula.authutil.interfaces import PrincipalIdAlreadyTaken
  37
  38
  39 class RWAuthProviders(Persistent, Contained):
  40     """Utility delivering IAuthProvider for principal ids
  41
  42     IAuthProvider objects are generated by dynamic adapter lookup from
  43     IAuthProviderAdaptable objects, which are retrieved from an internal
  44     mapping. Objects enter/leave the mapping through register/unregister.
  45
  46     Currently we do not support modification of principal id for registered
  47     objects; before doing anything that modifies the prinicipal id of an object,
  48     you need to unregister and reregister the object.
  49
  50     Currently, we maintain a two-way mapping, having a feeling that this comes
  51     in handy, in case of ObjectModifiedEvents, which might overcome the
  52     limitation about not changing registered objects. It is already used to
  53     prevent unregistered objects with the same principal id as an registered
  54     object, to remove the latter's mapping, when being passed to unregister.
  55
  56     This utility should be registered as a local utility, you probably want
  57     the persistent version (see below).
  58
  59     This utility could be registered globally and works outside of an
  60     application server. However, the adapter lookup for IAuthProvider needs
  61     to be supported.
  62
  63
  64     Mappings are empty, for a new utility
  65
  66         >>> apu = RWAuthProviders()
  67         >>> len(apu._ids)
  68         0
  69         >>> len(apu._objs)
  70         0
  71         >>> len(apu)
  72         0
  73
  74     Suitable object ends up in both mappings, strings work as id
  75
  76         >>> a = Mock(id = '1')
  77         >>> alsoProvides(a, IAuthProvider)
  78         >>> apu.register(a)
  79         >>> len(apu._ids)
  80         1
  81         >>> len(apu._objs)
  82         1
  83         >>> len(apu)
  84         1
  85         >>> apu._ids[a] is '1'
  86         True
  87         >>> apu._objs['1'] is a
  88         True
  89
  90     Object with same id as registered object triggers PrincipalIdAlreadyTaken
  91
  92         >>> b = Mock(id = '1')
  93         >>> alsoProvides(b, IAuthProvider)
  94         >>> apu.register(b)
  95         Traceback (most recent call last):
  96             blah
  97         PrincipalIdAlreadyTaken: 1
  98
  99     Unsuitable object triggers TypeError
 100
 101         >>> b = Mock(id = '2')
 102         >>> apu.register(b) # doctest: +IGNORE_EXCEPTION_DETAIL
 103         Traceback (most recent call last):
 104             blah
 105         TypeError: blah
 106
 107     More than one object can be added
 108
 109         >>> b = Mock(id = '2')
 110         >>> alsoProvides(b, IAuthProvider)
 111         >>> apu.register(b)
 112         >>> len(apu._ids)
 113         2
 114         >>> len(apu._objs)
 115         2
 116
 117     Objects are retrieved correctly
 118
 119         >>> apu['1'] is a
 120         True
 121         >>> apu['2'] is b
 122         True
 123     """
 124     implements(IRWAuthProviders)
 125
 126     def __init__(self):
 127         """
 128         """
 129         # XXX:
 130         # self might be stored in a persistent container
 131         # _ids and _objs are our only attributes and they won't change
 132         # I assume it is enough that the BTrees are persistent and that self
 133         # does not need to be...
 134         self._ids = queryUtility(IFactory, 'OOBTree', OOBTree.OOBTree)()
 135         self._objs = queryUtility(IFactory, 'OOBTree', OOBTree.OOBTree)()
 136
 137     def __contains__(self, id):
 138         return self.has_key(id)
 139
 140     def __getitem__(self, id):
 141         """get IAuthProvider object for principal id
 142         """
 143         obj = self._objs[id]
 144         ap = IAuthProvider(obj)
 145         return ap
 146
 147     def __len__(self):
 148         return self._ids.__len__()
 149
 150     def has_key(self, id):
 151         # I currently consider this a broken BTree
 152         return bool(self._objs.has_key(id))
 153
 154     def keys(self):
 155         # I currently consider this a broken BTree
 156         return list(self._objs.keys())
 157
 158     def register(self, obj):
 159         """Register an object.
 160
 161         It is assumed that an adapter lookup for IAuthProvider succeeds.
 162
 163         Fails with PrincipalIdAlreadyTaken, in case an object with the same
 164         principal id is registered already.
 165         """
 166         id = IAuthProvider(obj).id
 167         if self._objs.has_key(id):
 168             if self._objs[id] is not obj:
 169                 raise PrincipalIdAlreadyTaken, id
 170             return
 171         self._objs[id] = obj
 172         self._ids[obj] = id
 173         #notify(AuthProviderAdded(ob, event))
 174
 175     def unregister(self, obj):
 176         """Unregister an object.
 177
 178         Fails with KeyError, if the object is not registered.
 179         """
 180         # get id for obj, implicit check that obj is registered
 181         id = self._ids[obj]
 182         del self._objs[id]
 183         del self._ids[obj]
 184         #notify(AuthProviderRemoved(ob, event))