Metadata-Version: 2.1
Name: zope.pluggableauth
Version: 2.3.1
Summary: Pluggable Authentication Utility
Home-page: http://pypi.python.org/pypi/zope.pluggableauth
Author: Zope Foundation and Contributors
Author-email: zope-dev@zope.org
License: ZPL 2.1
Description: ========================
         ``zope.pluggableauth``
        ========================
        
        .. image:: https://travis-ci.com/zopefoundation/zope.pluggableauth.svg?branch=master
                :target: https://travis-ci.com/zopefoundation/zope.pluggableauth
        
        Based on ``zope.authentication``, this package provides a flexible and
        pluggable authentication utility, and provides a number of common plugins.
        
        
        ==================================
         Pluggable-Authentication Utility
        ==================================
        
        The Pluggable-Authentication Utility (PAU) provides a framework for
        authenticating principals and associating information with them. It uses
        plugins and subscribers to get its work done.
        
        For a pluggable-authentication utility to be used, it should be
        registered as a utility providing the
        `zope.authentication.interfaces.IAuthentication` interface.
        
        Authentication
        ==============
        
        The primary job of PAU is to authenticate principals. It uses two types of
        plug-ins in its work:
        
        - Credentials Plugins
        
        - Authenticator Plugins
        
        Credentials plugins are responsible for extracting user credentials from a
        request. A credentials plugin may in some cases issue a 'challenge' to obtain
        credentials. For example, a 'session' credentials plugin reads credentials
        from a session (the "extraction"). If it cannot find credentials, it will
        redirect the user to a login form in order to provide them (the "challenge").
        
        Authenticator plugins are responsible for authenticating the credentials
        extracted by a credentials plugin. They are also typically able to create
        principal objects for credentials they successfully authenticate.
        
        Given a request object, the PAU returns a principal object, if it can. The PAU
        does this by first iterating through its credentials plugins to obtain a
        set of credentials. If it gets credentials, it iterates through its
        authenticator plugins to authenticate them.
        
        If an authenticator succeeds in authenticating a set of credentials, the PAU
        uses the authenticator to create a principal corresponding to the credentials.
        The authenticator notifies subscribers if an authenticated principal is
        created. Subscribers are responsible for adding data, especially groups, to
        the principal. Typically, if a subscriber adds data, it should also add
        corresponding interface declarations.
        
        Simple Credentials Plugin
        -------------------------
        
        To illustrate, we'll create a simple credentials plugin:
        
          >>> from zope import interface
          >>> from zope.pluggableauth.authentication import interfaces
        
          >>> @interface.implementer(interfaces.ICredentialsPlugin)
          ... class MyCredentialsPlugin(object):
          ...
          ...     def extractCredentials(self, request):
          ...         return request.get('credentials')
          ...
          ...     def challenge(self, request):
          ...         pass # challenge is a no-op for this plugin
          ...
          ...     def logout(self, request):
          ...         pass # logout is a no-op for this plugin
        
        As a plugin, MyCredentialsPlugin needs to be registered as a named utility:
        
          >>> myCredentialsPlugin = MyCredentialsPlugin()
          >>> provideUtility(myCredentialsPlugin, name='My Credentials Plugin')
        
        Simple Authenticator Plugin
        ---------------------------
        
        Next we'll create a simple authenticator plugin. For our plugin, we'll need
        an implementation of IPrincipalInfo:
        
          >>> @interface.implementer(interfaces.IPrincipalInfo)
          ... class PrincipalInfo(object):
          ...
          ...     def __init__(self, id, title, description):
          ...         self.id = id
          ...         self.title = title
          ...         self.description = description
          ...
          ...     def __repr__(self):
          ...         return 'PrincipalInfo(%r)' % self.id
        
        Our authenticator uses this type when it creates a principal info:
        
          >>> @interface.implementer(interfaces.IAuthenticatorPlugin)
          ... class MyAuthenticatorPlugin(object):
          ...
          ...     def authenticateCredentials(self, credentials):
          ...         if credentials == 'secretcode':
          ...             return PrincipalInfo('bob', 'Bob', '')
          ...
          ...     def principalInfo(self, id):
          ...         pass # plugin not currently supporting search
        
        As with the credentials plugin, the authenticator plugin must be registered
        as a named utility:
        
          >>> myAuthenticatorPlugin = MyAuthenticatorPlugin()
          >>> provideUtility(myAuthenticatorPlugin, name='My Authenticator Plugin')
        
        Configuring a PAU
        -----------------
        
        Finally, we'll create the PAU itself:
        
          >>> from zope.pluggableauth import authentication
          >>> pau = authentication.PluggableAuthentication('xyz_')
        
        and configure it with the two plugins:
        
          >>> pau.credentialsPlugins = ('My Credentials Plugin', )
          >>> pau.authenticatorPlugins = ('My Authenticator Plugin', )
        
        Using the PAU to Authenticate
        -----------------------------
        
          >>> from zope.pluggableauth.factories import AuthenticatedPrincipalFactory
          >>> provideAdapter(AuthenticatedPrincipalFactory)
        
        We can now use the PAU to authenticate a sample request:
        
          >>> from zope.publisher.browser import TestRequest
          >>> print(pau.authenticate(TestRequest()))
          None
        
        In this case, we cannot authenticate an empty request. In the same way, we
        will not be able to authenticate a request with the wrong credentials:
        
          >>> print(pau.authenticate(TestRequest(credentials='let me in!')))
          None
        
        However, if we provide the proper credentials:
        
          >>> request = TestRequest(credentials='secretcode')
          >>> principal = pau.authenticate(request)
          >>> principal
          Principal('xyz_bob')
        
        we get an authenticated principal.
        
        Multiple Authenticator Plugins
        ------------------------------
        
        The PAU works with multiple authenticator plugins. It uses each plugin, in the
        order specified in the PAU's authenticatorPlugins attribute, to authenticate
        a set of credentials.
        
        To illustrate, we'll create another authenticator:
        
          >>> class MyAuthenticatorPlugin2(MyAuthenticatorPlugin):
          ...
          ...     def authenticateCredentials(self, credentials):
          ...         if credentials == 'secretcode':
          ...             return PrincipalInfo('black', 'Black Spy', '')
          ...         elif credentials == 'hiddenkey':
          ...             return PrincipalInfo('white', 'White Spy', '')
        
          >>> provideUtility(MyAuthenticatorPlugin2(), name='My Authenticator Plugin 2')
        
        If we put it before the original authenticator:
        
          >>> pau.authenticatorPlugins = (
          ...     'My Authenticator Plugin 2',
          ...     'My Authenticator Plugin')
        
        Then it will be given the first opportunity to authenticate a request:
        
          >>> pau.authenticate(TestRequest(credentials='secretcode'))
          Principal('xyz_black')
        
        If neither plugins can authenticate, pau returns None:
        
          >>> print(pau.authenticate(TestRequest(credentials='let me in!!')))
          None
        
        When we change the order of the authenticator plugins:
        
          >>> pau.authenticatorPlugins = (
          ...     'My Authenticator Plugin',
          ...     'My Authenticator Plugin 2')
        
        we see that our original plugin is now acting first:
        
          >>> pau.authenticate(TestRequest(credentials='secretcode'))
          Principal('xyz_bob')
        
        The second plugin, however, gets a chance to authenticate if first does not:
        
          >>> pau.authenticate(TestRequest(credentials='hiddenkey'))
          Principal('xyz_white')
        
        Multiple Credentials Plugins
        ----------------------------
        
        As with with authenticators, we can specify multiple credentials plugins. To
        illustrate, we'll create a credentials plugin that extracts credentials from
        a request form:
        
          >>> @interface.implementer(interfaces.ICredentialsPlugin)
          ... class FormCredentialsPlugin:
          ...
          ...     def extractCredentials(self, request):
          ...         return request.form.get('my_credentials')
          ...
          ...     def challenge(self, request):
          ...         pass
          ...
          ...     def logout(request):
          ...         pass
        
          >>> provideUtility(FormCredentialsPlugin(),
          ...                name='Form Credentials Plugin')
        
        and insert the new credentials plugin before the existing plugin:
        
          >>> pau.credentialsPlugins = (
          ...     'Form Credentials Plugin',
          ...     'My Credentials Plugin')
        
        The PAU will use each plugin in order to try and obtain credentials from a
        request:
        
          >>> pau.authenticate(TestRequest(credentials='secretcode',
          ...                              form={'my_credentials': 'hiddenkey'}))
          Principal('xyz_white')
        
        In this case, the first credentials plugin succeeded in getting credentials
        from the form and the second authenticator was able to authenticate the
        credentials. Specifically, the PAU went through these steps:
        
        - Get credentials using 'Form Credentials Plugin'
        
        - Got 'hiddenkey' credentials using 'Form Credentials Plugin', try to
          authenticate using 'My Authenticator Plugin'
        
        - Failed to authenticate 'hiddenkey' with 'My Authenticator Plugin', try
          'My Authenticator Plugin 2'
        
        - Succeeded in authenticating with 'My Authenticator Plugin 2'
        
        Let's try a different scenario:
        
          >>> pau.authenticate(TestRequest(credentials='secretcode'))
          Principal('xyz_bob')
        
        In this case, the PAU went through these steps::
        
        - Get credentials using 'Form Credentials Plugin'
        
        - Failed to get credentials using 'Form Credentials Plugin', try
          'My Credentials Plugin'
        
        - Got 'scecretcode' credentials using 'My Credentials Plugin', try to
          authenticate using 'My Authenticator Plugin'
        
        - Succeeded in authenticating with 'My Authenticator Plugin'
        
        Let's try a slightly more complex scenario:
        
          >>> pau.authenticate(TestRequest(credentials='hiddenkey',
          ...                              form={'my_credentials': 'bogusvalue'}))
          Principal('xyz_white')
        
        This highlights PAU's ability to use multiple plugins for authentication:
        
        - Get credentials using 'Form Credentials Plugin'
        
        - Got 'bogusvalue' credentials using 'Form Credentials Plugin', try to
          authenticate using 'My Authenticator Plugin'
        
        - Failed to authenticate 'boguskey' with 'My Authenticator Plugin', try
          'My Authenticator Plugin 2'
        
        - Failed to authenticate 'boguskey' with 'My Authenticator Plugin 2' --
          there are no more authenticators to try, so lets try the next credentials
          plugin for some new credentials
        
        - Get credentials using 'My Credentials Plugin'
        
        - Got 'hiddenkey' credentials using 'My Credentials Plugin', try to
          authenticate using 'My Authenticator Plugin'
        
        - Failed to authenticate 'hiddenkey' using 'My Authenticator Plugin', try
          'My Authenticator Plugin 2'
        
        - Succeeded in authenticating with 'My Authenticator Plugin 2' (shouts and
          cheers!)
        
        Multiple Authenticator Plugins
        ------------------------------
        
        As with the other operations we've seen, the PAU uses multiple plugins to
        find a principal. If the first authenticator plugin can't find the requested
        principal, the next plugin is used, and so on.
        
          >>> @interface.implementer(interfaces.IAuthenticatorPlugin)
          ... class AnotherAuthenticatorPlugin:
          ...
          ...     def __init__(self):
          ...         self.infos = {}
          ...         self.ids = {}
          ...
          ...     def principalInfo(self, id):
          ...         return self.infos.get(id)
          ...
          ...     def authenticateCredentials(self, credentials):
          ...         id = self.ids.get(credentials)
          ...         if id is not None:
          ...             return self.infos[id]
          ...
          ...     def add(self, id, title, description, credentials):
          ...         self.infos[id] = PrincipalInfo(id, title, description)
          ...         self.ids[credentials] = id
        
        
        To illustrate, we'll create and register two authenticators:
        
          >>> authenticator1 = AnotherAuthenticatorPlugin()
          >>> provideUtility(authenticator1, name='Authentication Plugin 1')
        
          >>> authenticator2 = AnotherAuthenticatorPlugin()
          >>> provideUtility(authenticator2, name='Authentication Plugin 2')
        
        and add a principal to them:
        
          >>> authenticator1.add('bob', 'Bob', 'A nice guy', 'b0b')
          >>> authenticator1.add('white', 'White Spy', 'Sneaky', 'deathtoblack')
          >>> authenticator2.add('black', 'Black Spy', 'Also sneaky', 'deathtowhite')
        
        When we configure the PAU to use both searchable authenticators (note the
        order):
        
          >>> pau.authenticatorPlugins = (
          ...     'Authentication Plugin 2',
          ...     'Authentication Plugin 1')
        
        we register the factories for our principals:
        
          >>> from zope.pluggableauth.factories import FoundPrincipalFactory
          >>> provideAdapter(FoundPrincipalFactory)
        
        we see how the PAU uses both plugins:
        
          >>> pau.getPrincipal('xyz_white')
          Principal('xyz_white')
        
          >>> pau.getPrincipal('xyz_black')
          Principal('xyz_black')
        
        If more than one plugin know about the same principal ID, the first plugin is
        used and the remaining are not delegated to. To illustrate, we'll add
        another principal with the same ID as an existing principal:
        
          >>> authenticator2.add('white', 'White Rider', '', 'r1der')
          >>> pau.getPrincipal('xyz_white').title
          'White Rider'
        
        If we change the order of the plugins:
        
          >>> pau.authenticatorPlugins = (
          ...     'Authentication Plugin 1',
          ...     'Authentication Plugin 2')
        
        we get a different principal for ID 'white':
        
          >>> pau.getPrincipal('xyz_white').title
          'White Spy'
        
        
        Issuing a Challenge
        ===================
        
        Part of PAU's IAuthentication contract is to challenge the user for
        credentials when its 'unauthorized' method is called. The need for this
        functionality is driven by the following use case:
        
        - A user attempts to perform an operation he is not authorized to perform.
        
        - A handler responds to the unauthorized error by calling IAuthentication
          'unauthorized'.
        
        - The authentication component (in our case, a PAU) issues a challenge to
          the user to collect new credentials (typically in the form of logging in
          as a new user).
        
        The PAU handles the credentials challenge by delegating to its credentials
        plugins.
        
        Currently, the PAU is configured with the credentials plugins that don't
        perform any action when asked to challenge (see above the 'challenge' methods).
        
        To illustrate challenges, we'll subclass an existing credentials plugin and
        do something in its 'challenge':
        
          >>> class LoginFormCredentialsPlugin(FormCredentialsPlugin):
          ...
          ...     def __init__(self, loginForm):
          ...         self.loginForm = loginForm
          ...
          ...     def challenge(self, request):
          ...         request.response.redirect(self.loginForm)
          ...         return True
        
        This plugin handles a challenge by redirecting the response to a login form.
        It returns True to signal to the PAU that it handled the challenge.
        
        We will now create and register a couple of these plugins:
        
          >>> provideUtility(LoginFormCredentialsPlugin('simplelogin.html'),
          ...                name='Simple Login Form Plugin')
        
          >>> provideUtility(LoginFormCredentialsPlugin('advancedlogin.html'),
          ...                name='Advanced Login Form Plugin')
        
        and configure the PAU to use them:
        
          >>> pau.credentialsPlugins = (
          ...     'Simple Login Form Plugin',
          ...     'Advanced Login Form Plugin')
        
        Now when we call 'unauthorized' on the PAU:
        
          >>> request = TestRequest()
          >>> pau.unauthorized(id=None, request=request)
        
        we see that the user is redirected to the simple login form:
        
          >>> request.response.getStatus()
          302
          >>> request.response.getHeader('location')
          'simplelogin.html'
        
        We can change the challenge policy by reordering the plugins:
        
          >>> pau.credentialsPlugins = (
          ...     'Advanced Login Form Plugin',
          ...     'Simple Login Form Plugin')
        
        Now when we call 'unauthorized':
        
          >>> request = TestRequest()
          >>> pau.unauthorized(id=None, request=request)
        
        the advanced plugin is used because it's first:
        
          >>> request.response.getStatus()
          302
          >>> request.response.getHeader('location')
          'advancedlogin.html'
        
        Challenge Protocols
        -------------------
        
        Sometimes, we want multiple challengers to work together. For example, the
        HTTP specification allows multiple challenges to be issued in a response. A
        challenge plugin can provide a `challengeProtocol` attribute that effectively
        groups related plugins together for challenging. If a plugin returns `True`
        from its challenge and provides a non-None challengeProtocol, subsequent
        plugins in the credentialsPlugins list that have the same challenge protocol
        will also be used to challenge.
        
        Without a challengeProtocol, only the first plugin to succeed in a challenge
        will be used.
        
        Let's look at an example. We'll define a new plugin that specifies an
        'X-Challenge' protocol:
        
          >>> class XChallengeCredentialsPlugin(FormCredentialsPlugin):
          ...
          ...     challengeProtocol = 'X-Challenge'
          ...
          ...     def __init__(self, challengeValue):
          ...         self.challengeValue = challengeValue
          ...
          ...     def challenge(self, request):
          ...         value = self.challengeValue
          ...         existing = request.response.getHeader('X-Challenge', '')
          ...         if existing:
          ...             value += ' ' + existing
          ...         request.response.setHeader('X-Challenge', value)
          ...         return True
        
        and register a couple instances as utilities:
        
          >>> provideUtility(XChallengeCredentialsPlugin('basic'),
          ...                name='Basic X-Challenge Plugin')
        
          >>> provideUtility(XChallengeCredentialsPlugin('advanced'),
          ...                name='Advanced X-Challenge Plugin')
        
        When we use both plugins with the PAU:
        
          >>> pau.credentialsPlugins = (
          ...     'Basic X-Challenge Plugin',
          ...     'Advanced X-Challenge Plugin')
        
        and call 'unauthorized':
        
          >>> request = TestRequest()
          >>> pau.unauthorized(None, request)
        
        we see that both plugins participate in the challenge, rather than just the
        first plugin:
        
          >>> request.response.getHeader('X-Challenge')
          'advanced basic'
        
        
        Pluggable-Authentication Prefixes
        =================================
        
        Principal ids are required to be unique system wide. Plugins will often provide
        options for providing id prefixes, so that different sets of plugins provide
        unique ids within a PAU. If there are multiple pluggable-authentication
        utilities in a system, it's a good idea to give each PAU a unique prefix, so
        that principal ids from different PAUs don't conflict. We can provide a prefix
        when a PAU is created:
        
          >>> pau = authentication.PluggableAuthentication('mypau_')
          >>> pau.credentialsPlugins = ('My Credentials Plugin', )
          >>> pau.authenticatorPlugins = ('My Authenticator Plugin', )
        
        When we create a request and try to authenticate:
        
          >>> pau.authenticate(TestRequest(credentials='secretcode'))
          Principal('mypau_bob')
        
        Note that now, our principal's id has the pluggable-authentication
        utility prefix.
        
        We can still lookup a principal, as long as we supply the prefix::
        
          >> pau.getPrincipal('mypas_42')
          Principal('mypas_42', "{'domain': 42}")
        
          >> pau.getPrincipal('mypas_41')
          OddPrincipal('mypas_41', "{'int': 41}")
        
        
        ==================
         Principal Folder
        ==================
        
        Principal folders contain principal-information objects that contain principal
        information. We create an internal principal using the `InternalPrincipal`
        class:
        
          >>> from zope.pluggableauth.plugins.principalfolder import InternalPrincipal
          >>> p1 = InternalPrincipal('login1', '123', "Principal 1",
          ...     passwordManagerName="SHA1")
          >>> p2 = InternalPrincipal('login2', '456', "The Other One")
        
        and add them to a principal folder:
        
          >>> from zope.pluggableauth.plugins.principalfolder import PrincipalFolder
          >>> principals = PrincipalFolder(u'principal.')
          >>> principals['p1'] = p1
          >>> principals['p2'] = p2
        
        Authentication
        ==============
        
        Principal folders provide the `IAuthenticatorPlugin` interface. When we
        provide suitable credentials:
        
          >>> from pprint import pprint
          >>> principals.authenticateCredentials({'login': 'login1', 'password': '123'})
          PrincipalInfo(u'principal.p1')
        
        We get back a principal id and supplementary information, including the
        principal title and description.  Note that the principal id is a concatenation
        of the principal-folder prefix and the name of the principal-information object
        within the folder.
        
        None is returned if the credentials are invalid:
        
          >>> principals.authenticateCredentials({'login': 'login1',
          ...                                     'password': '1234'})
          >>> principals.authenticateCredentials(42)
        
        Search
        ======
        
        Principal folders also provide the IQuerySchemaSearch interface.  This
        supports both finding principal information based on their ids:
        
          >>> principals.principalInfo('principal.p1')
          PrincipalInfo('principal.p1')
        
          >>> principals.principalInfo('p1')
        
        and searching for principals based on a search string:
        
          >>> list(principals.search({'search': 'other'}))
          [u'principal.p2']
        
          >>> list(principals.search({'search': 'OTHER'}))
          [u'principal.p2']
        
          >>> list(principals.search({'search': ''}))
          [u'principal.p1', u'principal.p2']
        
          >>> list(principals.search({'search': 'eek'}))
          []
        
          >>> list(principals.search({}))
          []
        
        If there are a large number of matches:
        
          >>> for i in range(20):
          ...     i = str(i)
          ...     p = InternalPrincipal('l'+i, i, "Dude "+i)
          ...     principals[i] = p
        
          >>> pprint(list(principals.search({'search': 'D'})), width=25)
          [u'principal.0',
           u'principal.1',
           u'principal.10',
           u'principal.11',
           u'principal.12',
           u'principal.13',
           u'principal.14',
           u'principal.15',
           u'principal.16',
           u'principal.17',
           u'principal.18',
           u'principal.19',
           u'principal.2',
           u'principal.3',
           u'principal.4',
           u'principal.5',
           u'principal.6',
           u'principal.7',
           u'principal.8',
           u'principal.9']
        
        We can use batching parameters to specify a subset of results:
        
          >>> pprint(list(principals.search({'search': 'D'}, start=17)))
          [u'principal.7', u'principal.8', u'principal.9']
        
          >>> pprint(list(principals.search({'search': 'D'}, batch_size=5)), width=60)
          [u'principal.0',
           u'principal.1',
           u'principal.10',
           u'principal.11',
           u'principal.12']
        
          >>> pprint(list(principals.search({'search': 'D'}, start=5, batch_size=5)),
          ...        width=25)
          [u'principal.13',
           u'principal.14',
           u'principal.15',
           u'principal.16',
           u'principal.17']
        
        There is an additional method that allows requesting the principal id
        associated with a login id.  The method raises KeyError when there is
        no associated principal:
        
          >>> principals.getIdByLogin("not-there")
          Traceback (most recent call last):
          KeyError: 'not-there'
        
        If there is a matching principal, the id is returned:
        
          >>> principals.getIdByLogin("login1")
          u'principal.p1'
        
        Changing credentials
        ====================
        
        Credentials can be changed by modifying principal-information objects:
        
          >>> p1.login = 'bob'
          >>> p1.password = 'eek'
        
          >>> principals.authenticateCredentials({'login': 'bob', 'password': 'eek'})
          PrincipalInfo(u'principal.p1')
        
          >>> principals.authenticateCredentials({'login': 'login1',
          ...                                     'password': 'eek'})
        
          >>> principals.authenticateCredentials({'login': 'bob',
          ...                                     'password': '123'})
        
        
        It is an error to try to pick a login name that is already taken:
        
          >>> p1.login = 'login2'
          Traceback (most recent call last):
          ...
          ValueError: Principal Login already taken!
        
        If such an attempt is made, the data are unchanged:
        
          >>> principals.authenticateCredentials({'login': 'bob', 'password': 'eek'})
          PrincipalInfo(u'principal.p1')
        
        Removing principals
        ===================
        
        Of course, if a principal is removed, we can no-longer authenticate it:
        
          >>> del principals['p1']
          >>> principals.authenticateCredentials({'login': 'bob',
          ...                                     'password': 'eek'})
        
        
        ===============
         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.pluggableauth.plugins.groupfolder
          >>> g1 = zope.pluggableauth.plugins.groupfolder.GroupInformation("Group 1")
        
          >>> groups = zope.pluggableauth.plugins.groupfolder.GroupFolder('group.')
          >>> groups['g1'] = g1
        
        Note that when group-info is added, a GroupAdded event is generated:
        
          >>> from zope.pluggableauth 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.pluggableauth.plugins.groupfolder import setGroupsForPrincipal
        
          >>> @interface.implementer(IGroupAwarePrincipal)
          ... class Principal:
          ...     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.pluggableauth.plugins import principalfolder
        
          >>> @interface.implementer(IAuthentication)
          ... class Principals:
          ...     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.pluggableauth.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.pluggableauth.plugins.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):
          ...
          zope.pluggableauth.plugins.groupfolder.GroupCycle: (u'auth.group.G2', [u'auth.group.G2', u'auth.group.G1'])
        
        Trying to do so does not fire an event.
        
          >>> getEvents(interfaces.IPrincipalsAddedToGroup)[-1] is old
          True
        
        They need not be hierarchical:
        
          >>> ga = zope.pluggableauth.plugins.groupfolder.GroupInformation("Group A")
          >>> groups['GA'] = ga
        
          >>> gb = zope.pluggableauth.plugins.groupfolder.GroupInformation("Group B")
          >>> groups['GB'] = gb
          >>> gb.principals = ['auth.group.GA']
        
          >>> gc = zope.pluggableauth.plugins.groupfolder.GroupInformation("Group C")
          >>> groups['GC'] = gc
          >>> gc.principals = ['auth.group.GA']
        
          >>> gd = zope.pluggableauth.plugins.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
          >>> @interface.implementer(zope.security.interfaces.IGroupAwarePrincipal)
          ... class GroupAwarePrincipal(Principal):
          ...     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.pluggableauth.plugins.groupfolder.specialGroups(event)
          >>> prin.groups
          []
        
        Now, if we define the Everybody group:
        
          >>> import zope.authentication.interfaces
          >>> @interface.implementer(zope.authentication.interfaces.IEveryoneGroup)
          ... class EverybodyGroup(Principal):
          ...     pass
        
          >>> everybody = EverybodyGroup('all')
          >>> provideUtility(everybody, zope.authentication.interfaces.IEveryoneGroup)
        
        Then the group will be added to the principal:
        
          >>> zope.pluggableauth.plugins.groupfolder.specialGroups(event)
          >>> prin.groups
          ['all']
        
        Similarly for the authenticated group:
        
          >>> @interface.implementer(
          ...         zope.authentication.interfaces.IAuthenticatedGroup)
          ... class AuthenticatedGroup(Principal):
          ...     pass
        
          >>> authenticated = AuthenticatedGroup('auth')
          >>> provideUtility(authenticated, zope.authentication.interfaces.IAuthenticatedGroup)
        
        Then the group will be added to the principal:
        
          >>> prin.groups = []
          >>> zope.pluggableauth.plugins.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.pluggableauth.plugins.groupfolder.specialGroups(event)
          >>> prin.groups
          []
        
        And they are only added to group aware principals:
        
          >>> @interface.implementer(zope.security.interfaces.IPrincipal)
          ... class SolitaryPrincipal:
          ...     id = title = description = ''
        
          >>> event = interfaces.FoundPrincipalCreated(42, SolitaryPrincipal(), {})
          >>> zope.pluggableauth.plugins.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...
        
            >>> @interface.implementer(
            ...         zope.pluggableauth.plugins.groupfolder.IGroupInformation)
            ... class DemoGroupInformation(object):
            ...     def __init__(self, title, description, principals):
            ...         self.title = title
            ...         self.description = description
            ...         self.principals = principals
            ...
            >>> i = DemoGroupInformation(
            ...     'Managers', 'Taskmasters', ('joe', 'jane'))
            ...
            >>> info = zope.pluggableauth.plugins.groupfolder.GroupInfo(
            ...     'groups.managers', i)
            >>> @interface.implementer(IGroupAwarePrincipal)
            ... class DummyGroup(object):
            ...     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.pluggableauth.plugins.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.
        
        * 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,
        
        * 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).
        
        
        =========
         Changes
        =========
        
        2.3.1 (2021-03-19)
        ==================
        
        - Drop support for Python 3.4.
        
        - Add support for Python 3.7.
        
        - Import from zope.interface.interfaces to avoid deprecation warning.
        
        
        2.3.0 (2017-11-12)
        ==================
        
        - Drop support for Python 3.3.
        
        
        2.2.0 (2017-05-02)
        ==================
        
        - Add support for Python 3.6.
        
        - Fix a NameError in the idpicker under Python 3.6.
          See `issue 7 <https://github.com/zopefoundation/zope.pluggableauth/issues/7>`_.
        
        2.1.0 (2016-07-04)
        ==================
        
        - Add support for Python 3.5.
        
        - Drop support for Python 2.6.
        
        
        2.0.0 (2014-12-24)
        ==================
        
        - Add support for Python 3.4.
        
        - Refactor ``zope.pluggableauth.plugins.session.redirectWithComeFrom``
          into a reusable function.
        
        - Fix: allow password containing colon(s) in HTTP basic authentication
          credentials extraction plug-in, to conform with RFC2617
        
        
        2.0.0a1 (2013-02-21)
        ====================
        
        - Add ``tox.ini`` and ``MANIFEST.in``.
        
        - Add support for Python 3.3.
        
        - Replace deprecated ``zope.component.adapts`` usage with equivalent
          ``zope.component.adapter`` decorator.
        
        - Replace deprecated ``zope.interface.implements`` usage with equivalent
          ``zope.interface.implementer`` decorator.
        
        - Drop support for Python 2.4 and 2.5.
        
        
        1.3 (2011-02-08)
        ================
        
        - As the ``camefrom`` information is most probably used for a redirect,
          require it to be an absolute URL (see also
          http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.30).
        
        1.2 (2010-12-16)
        ================
        
        - Add a hook to ``SessionCredentialsPlugin`` (``_makeCredentials``) that can
          be overriden in subclasses to store the credentials in the session
          differently.
        
          For example, you could use ``keas.kmi`` and encrypt the passwords of the
          currently logged-in users so they don't appear in plain text in the ZODB.
        
        1.1 (2010-10-18)
        ================
        
        - Move concrete ``IAuthenticatorPlugin`` implementations from
          ``zope.app.authentication`` to ``zope.pluggableauth.plugins``.
        
          As a result, projects that want to use the ``IAuthenticator`` plugins
          (previously found in ``zope.app.authentication``) do not automatically
          also pull in the ``zope.app.*`` dependencies that are needed to register
          the ZMI views.
        
        1.0.3 (2010-07-09)
        ==================
        
        - Fix dependency declaration.
        
        1.0.2 (2010-07-90)
        ==================
        
        - Add ``persistent.Persistent`` and ``zope.container.contained.Contained`` as
          bases for ``zope.pluggableauth.plugins.session.SessionCredentialsPlugin``,
          so instances of ``zope.app.authentication.session.SessionCredentialsPlugin``
          won't be changed.
          (https://mail.zope.org/pipermail/zope-dev/2010-July/040898.html)
        
        1.0.1 (2010-02-11)
        ==================
        
        * Declare adapter in a new ZCML file : `principalfactories.zcml`.  Avoids
          duplication errors in ``zope.app.authentication``.
        
        1.0 (2010-02-05)
        ================
        
        * Splitting off from zope.app.authentication
        
Keywords: zope3 ztk authentication pluggable
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: Zope Public License
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
Classifier: Natural Language :: English
Classifier: Operating System :: OS Independent
Classifier: Topic :: Internet :: WWW/HTTP
Classifier: Framework :: Zope :: 3
Provides-Extra: test
