python-zope.pluggableauth 1.3-0ubuntu1 / usr / share / pyshared / zope.pluggableauth-1.3.egg-info / PKG-INFO

Metadata-Version: 1.1
Name: zope.pluggableauth
Version: 1.3
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: ==========================
         Pluggable Authentication
        ==========================
        
        Based on zope.authentication, this package provides a flexible and
        pluggable authentication utility. Several common plugins are provided.
        
        .. contents::
        
        
        =======
        Changes
        =======
        
        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)
        ----------------
        
        - SessionCredentialsPlugin has a hook (_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)
        ----------------
        
        * Moved 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)
        ------------------
        
        * Fixed dependency declaration.
        
        1.0.2 (2010-07-90)
        ------------------
        
        * Added persistent.Persistent and zope.container.contained.Contained as
          bases 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)
        ------------------
        
        * Adapters are now declared in a new ZCML file :
          `principalfactories.zcml`. This avoids duplication errors in
          ``zope.app.authentication``.
        
        1.0 (2010-02-05)
        ----------------
        
        * Splitting off from zope.app.authentication
        
        ================================
        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 iterateing 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
        
          >>> class MyCredentialsPlugin(object):
          ...
          ...     interface.implements(interfaces.ICredentialsPlugin)
          ...
          ...     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::
        
          >>> class PrincipalInfo(object):
          ...
          ...     interface.implements(interfaces.IPrincipalInfo)
          ...
          ...     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::
        
          >>> class MyAuthenticatorPlugin(object):
          ...
          ...     interface.implements(interfaces.IAuthenticatorPlugin)
          ...
          ...     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::
        
          >>> class FormCredentialsPlugin:
          ...
          ...     interface.implements(interfaces.ICredentialsPlugin)
          ...
          ...     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.
        
          >>> class AnotherAuthenticatorPlugin:
          ...
          ...     interface.implements(interfaces.IAuthenticatorPlugin)
          ...
          ...     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 challange, 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}")
        
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: Natural Language :: English
Classifier: Operating System :: OS Independent
Classifier: Topic :: Internet :: WWW/HTTP
Classifier: Framework :: Zope3