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Viewing changes to twisted/cred/service.py

  • Committer: glyph
  • Date: 2002-01-27 23:10:25 UTC
  • Revision ID: vcs-imports@canonical.com-20020127231025-6180b0f76c6aba84
Moved twisted.internet.passport into twisted.cred.

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twisted/cred/service.py
 
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"""
 
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Twisted Cred Service
 
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"""
 
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# Twisted Imports
 
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from twisted.python import defer
 
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# Sibling Imports
 
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from perspective import Perspective
 
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class Service:
 
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    """I am a service that internet applications interact with.
 
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    I represent a set of abstractions which users may interact with over a
 
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    specified protocol.
 
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    (See Also: twisted.spread.pb.Service)
 
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    """
 
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    # ugh, load order
 
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    perspectiveClass = Perspective
 
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    application = None
 
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    serviceType = None
 
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    serviceName = None
 
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    def __init__(self, serviceName, application=None):
 
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        """Create me, attached to the given application.
 
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        Arguments: application, a twisted.internet.app.Application instance.
 
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        """
 
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        self.serviceName = serviceName
 
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        self.perspectives = {}
 
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        self.setApplication(application)
 
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    def cachePerspective(self, perspective):
 
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        """Cache a perspective loaded from an external data source.
 
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        Perspectives that were 'loaded' from memory will not be uncached.
 
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        """
 
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        if self.perspectives.has_key(perspective.perspectiveName):
 
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            return
 
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        self.perspectives[perspective.perspectiveName] = perspective
 
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        perspective._service_cached = 1
 
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    def uncachePerspective(self, perspective):
 
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        """Uncache a perspective loaded from an external data source.
 
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        Perspectives that were 'loaded' from memory will not be uncached.
 
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        """
 
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        if self.perspectives.has_key(perspective.perspectiveName):
 
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            if perspective._service_cached:
 
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                del self.perspectives[perspective.perspectiveName]
 
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    def setApplication(self, application):
 
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        if self.application is not application:
 
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            assert not self.application, "Application already set!"
 
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        if application:
 
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            self.application = application
 
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            application.addService(self)
 
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    def createPerspective(self, name):
 
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        """Create a perspective from self.perspectiveClass and add it to this service.
 
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        """
 
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        p = self.perspectiveClass(name)
 
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        self.perspectives[name] = p
 
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        p.setService(self)
 
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        return p
 
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    def addPerspective(self, perspective):
 
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        """Add a perspective to this Service.
 
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        """
 
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        perspective.setService(self)
 
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        self.perspectives[perspective.getPerspectiveName()] = perspective
 
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    def getPerspectiveNamed(self, name):
 
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        """Return a perspective that represents a user for this service. (DEPRECATED)
 
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        Raises a KeyError if no such user exists.  Override this method to
 
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        provide dynamic instantiation of perspectives.
 
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        """
 
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        return self.perspectives[name]
 
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    def loadPerspective(self, name):
 
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        """Load a perspective from an external data-source.
 
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        If no such data-source exists, return None.  Implement this if you want
 
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        to load your perspectives from somewhere else (e.g. LDAP or a
 
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        database).  It is not recommended to call this directly, since
 
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        getPerspectiveRequest provides management of caching perspectives.
 
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        """
 
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        return defer.fail("No such perspective %s" % name)
 
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    def getPerspectiveRequest(self, name):
 
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        """Return a Deferred which is a request for a perspective on this service.
 
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        """
 
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        try:
 
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            p = self.getPerspectiveNamed(name)
 
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        except KeyError:
 
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            return self.loadPerspective(name)
 
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        else:
 
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            return defer.succeed(p)
 
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    def getServiceName(self):
 
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        """The name of this service.
 
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        """
 
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        return self.serviceName or self.getServiceType()
 
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    def getServiceType(self):
 
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        """Get a string describing the type of this service.
 
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        """
 
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        return self.serviceType or str(self.__class__)
 
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