/usr/share/pyshared/zope/app/authentication/groupfolder.txt is in python-zope.app.authentication 3.9-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 | =============
Group Folders
=============
Group folders provide support for groups information stored in the ZODB. They
are persistent, and must be contained within the PAUs that use them.
Like other principals, groups are created when they are needed.
Group folders contain group-information objects that contain group information.
We create group information using the `GroupInformation` class:
>>> import zope.app.authentication.groupfolder
>>> g1 = zope.app.authentication.groupfolder.GroupInformation("Group 1")
>>> groups = zope.app.authentication.groupfolder.GroupFolder('group.')
>>> groups['g1'] = g1
Note that when group-info is added, a GroupAdded event is generated:
>>> from zope.app.authentication import interfaces
>>> from zope.component.eventtesting import getEvents
>>> getEvents(interfaces.IGroupAdded)
[<GroupAdded 'group.g1'>]
Groups are defined with respect to an authentication service. Groups
must be accessible via an authentication service and can contain
principals accessible via an authentication service.
To illustrate the group interaction with the authentication service,
we'll create a sample authentication service:
>>> from zope import interface
>>> from zope.authentication.interfaces import IAuthentication
>>> from zope.authentication.interfaces import PrincipalLookupError
>>> from zope.security.interfaces import IGroupAwarePrincipal
>>> from zope.app.authentication.groupfolder import setGroupsForPrincipal
>>> class Principal:
... interface.implements(IGroupAwarePrincipal)
... def __init__(self, id, title='', description=''):
... self.id, self.title, self.description = id, title, description
... self.groups = []
>>> class PrincipalCreatedEvent:
... def __init__(self, authentication, principal):
... self.authentication = authentication
... self.principal = principal
>>> from zope.app.authentication import principalfolder
>>> class Principals:
...
... interface.implements(IAuthentication)
...
... def __init__(self, groups, prefix='auth.'):
... self.prefix = prefix
... self.principals = {
... 'p1': principalfolder.PrincipalInfo('p1', '', '', ''),
... 'p2': principalfolder.PrincipalInfo('p2', '', '', ''),
... 'p3': principalfolder.PrincipalInfo('p3', '', '', ''),
... 'p4': principalfolder.PrincipalInfo('p4', '', '', ''),
... }
... self.groups = groups
... groups.__parent__ = self
...
... def getAuthenticatorPlugins(self):
... return [('principals', self.principals), ('groups', self.groups)]
...
... def getPrincipal(self, id):
... if not id.startswith(self.prefix):
... raise PrincipalLookupError(id)
... id = id[len(self.prefix):]
... info = self.principals.get(id)
... if info is None:
... info = self.groups.principalInfo(id)
... if info is None:
... raise PrincipalLookupError(id)
... principal = Principal(self.prefix+info.id,
... info.title, info.description)
... setGroupsForPrincipal(PrincipalCreatedEvent(self, principal))
... return principal
This class doesn't really implement the full `IAuthentication` interface, but
it implements the `getPrincipal` method used by groups. It works very much
like the pluggable authentication utility. It creates principals on demand. It
calls `setGroupsForPrincipal`, which is normally called as an event subscriber,
when principals are created. In order for `setGroupsForPrincipal` to find out
group folder, we have to register it as a utility:
>>> from zope.app.authentication.interfaces import IAuthenticatorPlugin
>>> from zope.component import provideUtility
>>> provideUtility(groups, IAuthenticatorPlugin)
We will create and register a new principals utility:
>>> principals = Principals(groups)
>>> provideUtility(principals, IAuthentication)
Now we can set the principals on the group:
>>> g1.principals = ['auth.p1', 'auth.p2']
>>> g1.principals
('auth.p1', 'auth.p2')
Adding principals fires an event.
>>> getEvents(interfaces.IPrincipalsAddedToGroup)[-1]
<PrincipalsAddedToGroup ['auth.p1', 'auth.p2'] u'auth.group.g1'>
We can now look up groups for the principals:
>>> groups.getGroupsForPrincipal('auth.p1')
(u'group.g1',)
Note that the group id is a concatenation of the group-folder prefix
and the name of the group-information object within the folder.
If we delete a group:
>>> del groups['g1']
then the groups folder loses the group information for that group's
principals:
>>> groups.getGroupsForPrincipal('auth.p1')
()
but the principal information on the group is unchanged:
>>> g1.principals
('auth.p1', 'auth.p2')
It also fires an event showing that the principals are removed from the group
(g1 is group information, not a zope.security.interfaces.IGroup).
>>> getEvents(interfaces.IPrincipalsRemovedFromGroup)[-1]
<PrincipalsRemovedFromGroup ['auth.p1', 'auth.p2'] u'auth.group.g1'>
Adding the group sets the folder principal information. Let's use a
different group name:
>>> groups['G1'] = g1
>>> groups.getGroupsForPrincipal('auth.p1')
(u'group.G1',)
Here we see that the new name is reflected in the group information.
An event is fired, as usual.
>>> getEvents(interfaces.IPrincipalsAddedToGroup)[-1]
<PrincipalsAddedToGroup ['auth.p1', 'auth.p2'] u'auth.group.G1'>
In terms of member events (principals added and removed from groups), we have
now seen that events are fired when a group information object is added and
when it is removed from a group folder; and we have seen that events are fired
when a principal is added to an already-registered group. Events are also
fired when a principal is removed from an already-registered group. Let's
quickly see some more examples.
>>> g1.principals = ('auth.p1', 'auth.p3', 'auth.p4')
>>> getEvents(interfaces.IPrincipalsAddedToGroup)[-1]
<PrincipalsAddedToGroup ['auth.p3', 'auth.p4'] u'auth.group.G1'>
>>> getEvents(interfaces.IPrincipalsRemovedFromGroup)[-1]
<PrincipalsRemovedFromGroup ['auth.p2'] u'auth.group.G1'>
>>> g1.principals = ('auth.p1', 'auth.p2')
>>> getEvents(interfaces.IPrincipalsAddedToGroup)[-1]
<PrincipalsAddedToGroup ['auth.p2'] u'auth.group.G1'>
>>> getEvents(interfaces.IPrincipalsRemovedFromGroup)[-1]
<PrincipalsRemovedFromGroup ['auth.p3', 'auth.p4'] u'auth.group.G1'>
Groups can contain groups:
>>> g2 = zope.app.authentication.groupfolder.GroupInformation("Group Two")
>>> groups['G2'] = g2
>>> g2.principals = ['auth.group.G1']
>>> groups.getGroupsForPrincipal('auth.group.G1')
(u'group.G2',)
>>> old = getEvents(interfaces.IPrincipalsAddedToGroup)[-1]
>>> old
<PrincipalsAddedToGroup ['auth.group.G1'] u'auth.group.G2'>
Groups cannot contain cycles:
>>> g1.principals = ('auth.p1', 'auth.p2', 'auth.group.G2')
... # doctest: +NORMALIZE_WHITESPACE
Traceback (most recent call last):
...
GroupCycle: (u'auth.group.G1',
['auth.p2', u'auth.group.G1', u'auth.group.G2'])
Trying to do so does not fire an event.
>>> getEvents(interfaces.IPrincipalsAddedToGroup)[-1] is old
True
They need not be hierarchical:
>>> ga = zope.app.authentication.groupfolder.GroupInformation("Group A")
>>> groups['GA'] = ga
>>> gb = zope.app.authentication.groupfolder.GroupInformation("Group B")
>>> groups['GB'] = gb
>>> gb.principals = ['auth.group.GA']
>>> gc = zope.app.authentication.groupfolder.GroupInformation("Group C")
>>> groups['GC'] = gc
>>> gc.principals = ['auth.group.GA']
>>> gd = zope.app.authentication.groupfolder.GroupInformation("Group D")
>>> groups['GD'] = gd
>>> gd.principals = ['auth.group.GA', 'auth.group.GB']
>>> ga.principals = ['auth.p1']
Group folders provide a very simple search interface. They perform
simple string searches on group titles and descriptions.
>>> list(groups.search({'search': 'grou'})) # doctest: +NORMALIZE_WHITESPACE
[u'group.G1', u'group.G2',
u'group.GA', u'group.GB', u'group.GC', u'group.GD']
>>> list(groups.search({'search': 'two'}))
[u'group.G2']
They also support batching:
>>> list(groups.search({'search': 'grou'}, 2, 3))
[u'group.GA', u'group.GB', u'group.GC']
If you don't supply a search key, no results will be returned:
>>> list(groups.search({}))
[]
Identifying groups
------------------
The function, `setGroupsForPrincipal`, is a subscriber to
principal-creation events. It adds any group-folder-defined groups to
users in those groups:
>>> principal = principals.getPrincipal('auth.p1')
>>> principal.groups
[u'auth.group.G1', u'auth.group.GA']
Of course, this applies to groups too:
>>> principal = principals.getPrincipal('auth.group.G1')
>>> principal.id
'auth.group.G1'
>>> principal.groups
[u'auth.group.G2']
In addition to setting principal groups, the `setGroupsForPrincipal`
function also declares the `IGroup` interface on groups:
>>> [iface.__name__ for iface in interface.providedBy(principal)]
['IGroup', 'IGroupAwarePrincipal']
>>> [iface.__name__
... for iface in interface.providedBy(principals.getPrincipal('auth.p1'))]
['IGroupAwarePrincipal']
Special groups
--------------
Two special groups, Authenticated, and Everyone may apply to users
created by the pluggable-authentication utility. There is a
subscriber, specialGroups, that will set these groups on any non-group
principals if IAuthenticatedGroup, or IEveryoneGroup utilities are
provided.
Lets define a group-aware principal:
>>> import zope.security.interfaces
>>> class GroupAwarePrincipal(Principal):
... interface.implements(zope.security.interfaces.IGroupAwarePrincipal)
... def __init__(self, id):
... Principal.__init__(self, id)
... self.groups = []
If we notify the subscriber with this principal, nothing will happen
because the groups haven't been defined:
>>> prin = GroupAwarePrincipal('x')
>>> event = interfaces.FoundPrincipalCreated(42, prin, {})
>>> zope.app.authentication.groupfolder.specialGroups(event)
>>> prin.groups
[]
Now, if we define the Everybody group:
>>> import zope.authentication.interfaces
>>> class EverybodyGroup(Principal):
... interface.implements(zope.authentication.interfaces.IEveryoneGroup)
>>> everybody = EverybodyGroup('all')
>>> provideUtility(everybody, zope.authentication.interfaces.IEveryoneGroup)
Then the group will be added to the principal:
>>> zope.app.authentication.groupfolder.specialGroups(event)
>>> prin.groups
['all']
Similarly for the authenticated group:
>>> class AuthenticatedGroup(Principal):
... interface.implements(
... zope.authentication.interfaces.IAuthenticatedGroup)
>>> authenticated = AuthenticatedGroup('auth')
>>> provideUtility(authenticated, zope.authentication.interfaces.IAuthenticatedGroup)
Then the group will be added to the principal:
>>> prin.groups = []
>>> zope.app.authentication.groupfolder.specialGroups(event)
>>> prin.groups.sort()
>>> prin.groups
['all', 'auth']
These groups are only added to non-group principals:
>>> prin.groups = []
>>> interface.directlyProvides(prin, zope.security.interfaces.IGroup)
>>> zope.app.authentication.groupfolder.specialGroups(event)
>>> prin.groups
[]
And they are only added to group aware principals:
>>> class SolitaryPrincipal:
... interface.implements(zope.security.interfaces.IPrincipal)
... id = title = description = ''
>>> event = interfaces.FoundPrincipalCreated(42, SolitaryPrincipal(), {})
>>> zope.app.authentication.groupfolder.specialGroups(event)
>>> prin.groups
[]
Member-aware groups
-------------------
The groupfolder includes a subscriber that gives group principals the
zope.security.interfaces.IGroupAware interface and an implementation thereof.
This allows groups to be able to get and set their members.
Given an info object and a group...
>>> class DemoGroupInformation(object):
... interface.implements(
... zope.app.authentication.groupfolder.IGroupInformation)
... def __init__(self, title, description, principals):
... self.title = title
... self.description = description
... self.principals = principals
...
>>> i = DemoGroupInformation(
... 'Managers', 'Taskmasters', ('joe', 'jane'))
...
>>> info = zope.app.authentication.groupfolder.GroupInfo(
... 'groups.managers', i)
>>> class DummyGroup(object):
... interface.implements(IGroupAwarePrincipal)
... def __init__(self, id, title=u'', description=u''):
... self.id = id
... self.title = title
... self.description = description
... self.groups = []
...
>>> principal = DummyGroup('foo')
>>> zope.security.interfaces.IMemberAwareGroup.providedBy(principal)
False
...when you call the subscriber, it adds the two pseudo-methods to the
principal and makes the principal provide the IMemberAwareGroup interface.
>>> zope.app.authentication.groupfolder.setMemberSubscriber(
... interfaces.FoundPrincipalCreated(
... 'dummy auth (ignored)', principal, info))
>>> principal.getMembers()
('joe', 'jane')
>>> principal.setMembers(('joe', 'jane', 'jaimie'))
>>> principal.getMembers()
('joe', 'jane', 'jaimie')
>>> zope.security.interfaces.IMemberAwareGroup.providedBy(principal)
True
The two methods work with the value on the IGroupInformation object.
>>> i.principals == principal.getMembers()
True
Limitation
==========
The current group-folder design has an important limitation!
There is no point in assigning principals to a group
from a group folder unless the principal is from the same pluggable
authentication utility.
o If a principal is from a higher authentication utility, the user
will not get the group definition. Why? Because the principals
group assignments are set when the principal is authenticated. At
that point, the current site is the site containing the principal
definition. Groups defined in lower sites will not be consulted,
o It is impossible to assign users from lower authentication
utilities because they can't be seen when managing the group,
from the site containing the group.
A better design might be to store user-role assignments independent of
the group definitions and to look for assignments during (url)
traversal. This could get quite complex though.
While it is possible to have multiple authentication utilities long a
URL path, it is generally better to stick to a simpler model in which
there is only one authentication utility along a URL path (in addition
to the global utility, which is used for bootstrapping purposes).
|