# -*- test-case-name: twisted.test.test_cred -*-
# Twisted, the Framework of Your Internet
# Copyright (C) 2001 Matthew W. Lefkowitz
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of version 2.1 of the GNU Lesser General Public
# License as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""
Twisted Cred Service
Maintainer: U{Glyph Lefkowitz<mailto:glyph@twistedmatrix.com>}
Stability: semi-stable
Future Plans: This module needs a little bit of finalization and cleanup, and
will probably have the errors for missing or non-cached perspectives be more
clearly defined.
"""
# Twisted Imports
from twisted.python import log,components,reflect
from twisted.internet import defer,app
# Sibling Imports
from perspective import Perspective
# System Imports
import types
import warnings
class IService(components.Interface):
"""An authorized service for internet applications.
"""
class Service(app.ApplicationService):
"""I am a service that internet applications interact with.
I represent a set of abstractions which users may interact with over a
specified protocol.
@see: L{twisted.spread.pb.Service}
"""
__implements__ = IService
# ugh, load order
perspectiveClass = Perspective
serviceType = None
serviceName = None
def __init__(self, serviceName, serviceParent=None, authorizer=None, application=None):
"""Create me, attached to the given application.
Arguments: application, a twisted.internet.app.Application instance.
"""
self.perspectives = {}
if application:
if serviceParent:
raise Exception(
"'serviceParent' supercedes the 'application' argument"
" -- you may not supply both. ('application' accepted"
"for backwards compatibility only.)")
else:
sp = application
else:
sp = serviceParent
if not authorizer:
if isinstance(sp, app.Application):
warnings.warn("You have to pass an authorizer separately from an application now.",
category=DeprecationWarning, stacklevel=2)
authorizer = sp.authorizer
self.authorizer = authorizer
app.ApplicationService.__init__(self, serviceName, serviceParent, application)
def cachePerspective(self, perspective):
"""Cache a perspective loaded from an external data source.
Perspectives that were 'loaded' from memory will not be uncached.
"""
if self.perspectives.has_key(perspective.perspectiveName):
return
self.perspectives[perspective.perspectiveName] = perspective
perspective._service_cached = 1
def uncachePerspective(self, perspective):
"""Uncache a perspective loaded from an external data source.
Perspectives that were 'loaded' from memory will not be uncached.
"""
if self.perspectives.has_key(perspective.perspectiveName):
if perspective._service_cached:
del self.perspectives[perspective.perspectiveName]
def createPerspective(self, name):
"""Create a perspective from self.perspectiveClass and add it to this service.
"""
p = self.perspectiveClass(name)
self.perspectives[name] = p
p.setService(self)
return p
def addPerspective(self, perspective):
"""Add a perspective to this Service.
"""
if not isinstance(perspective, Perspective):
raise TypeError
perspective.setService(self)
self.perspectives[perspective.getPerspectiveName()] = perspective
def getPerspectiveNamed(self, name):
"""Return a perspective that represents a user for this service. (DEPRECATED)
Raises a KeyError if no such user exists. Override this method to
provide dynamic instantiation of perspectives. It is only deprecated
to call this method directly, not to override it; when you need to get
a Perspective, call getPerspectiveRequest.
"""
return self.perspectives[name]
def loadPerspective(self, name):
"""Load a perspective from an external data-source.
If no such data-source exists, return None. Implement this if you want
to load your perspectives from somewhere else (e.g. LDAP or a
database). It is not recommended to call this directly, since
getPerspectiveRequest provides management of caching perspectives.
"""
return defer.fail("No such perspective %s" % name)
def getPerspectiveForIdentity(self, name, identity):
"""A hook to use if the identity is required when getting the perspective.
"""
return self.getPerspectiveRequest(name)
def getPerspectiveRequest(self, name):
"""Return a Deferred which is a request for a perspective on this service.
"""
try:
p = self.getPerspectiveNamed(name)
except KeyError:
return self.loadPerspective(name)
else:
return defer.succeed(p)
def getServiceName(self):
"""The name of this service.
"""
return self.serviceName or self.getServiceType()
def getServiceType(self):
"""Get a string describing the type of this service.
"""
return self.serviceType or reflect.qual(self.__class__)
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