# -*- test-case-name: twisted.test.test_pb -*- # Copyright (c) Twisted Matrix Laboratories. # See LICENSE for details. """ Perspective Broker \"This isn\'t a professional opinion, but it's probably got enough internet to kill you.\" --glyph Introduction ============ This is a broker for proxies for and copies of objects. It provides a translucent interface layer to those proxies. The protocol is not opaque, because it provides objects which represent the remote proxies and require no context (server references, IDs) to operate on. It is not transparent because it does I{not} attempt to make remote objects behave identically, or even similiarly, to local objects. Method calls are invoked asynchronously, and specific rules are applied when serializing arguments. To get started, begin with L{PBClientFactory} and L{PBServerFactory}. @author: Glyph Lefkowitz """ import random import types from hashlib import md5 from zope.interface import implements, Interface # Twisted Imports from twisted.python import log, failure, reflect from twisted.internet import defer, protocol from twisted.cred.portal import Portal from twisted.cred.credentials import IAnonymous, ICredentials from twisted.cred.credentials import IUsernameHashedPassword, Anonymous from twisted.persisted import styles from twisted.python.components import registerAdapter from twisted.spread.interfaces import IJellyable, IUnjellyable from twisted.spread.jelly import jelly, unjelly, globalSecurity from twisted.spread import banana from twisted.spread.flavors import Serializable from twisted.spread.flavors import Referenceable, NoSuchMethod from twisted.spread.flavors import Root, IPBRoot from twisted.spread.flavors import ViewPoint from twisted.spread.flavors import Viewable from twisted.spread.flavors import Copyable from twisted.spread.flavors import Jellyable from twisted.spread.flavors import Cacheable from twisted.spread.flavors import RemoteCopy from twisted.spread.flavors import RemoteCache from twisted.spread.flavors import RemoteCacheObserver from twisted.spread.flavors import copyTags from twisted.spread.flavors import setUnjellyableForClass from twisted.spread.flavors import setUnjellyableFactoryForClass from twisted.spread.flavors import setUnjellyableForClassTree # These three are backwards compatibility aliases for the previous three. # Ultimately they should be deprecated. -exarkun from twisted.spread.flavors import setCopierForClass from twisted.spread.flavors import setFactoryForClass from twisted.spread.flavors import setCopierForClassTree MAX_BROKER_REFS = 1024 portno = 8787 class ProtocolError(Exception): """ This error is raised when an invalid protocol statement is received. """ class DeadReferenceError(ProtocolError): """ This error is raised when a method is called on a dead reference (one whose broker has been disconnected). """ class Error(Exception): """ This error can be raised to generate known error conditions. When a PB callable method (perspective_, remote_, view_) raises this error, it indicates that a traceback should not be printed, but instead, the string representation of the exception should be sent. """ class RemoteError(Exception): """ This class is used to wrap a string-ified exception from the remote side to be able to reraise it. (Raising string exceptions is no longer possible in Python 2.6+) The value of this exception will be a str() representation of the remote value. @ivar remoteType: The full import path of the exception class which was raised on the remote end. @type remoteType: C{str} @ivar remoteTraceback: The remote traceback. @type remoteTraceback: C{str} @note: It's not possible to include the remoteTraceback if this exception is thrown into a generator. It must be accessed as an attribute. """ def __init__(self, remoteType, value, remoteTraceback): Exception.__init__(self, value) self.remoteType = remoteType self.remoteTraceback = remoteTraceback class RemoteMethod: """ This is a translucent reference to a remote message. """ def __init__(self, obj, name): """ Initialize with a L{RemoteReference} and the name of this message. """ self.obj = obj self.name = name def __cmp__(self, other): return cmp((self.obj, self.name), other) def __hash__(self): return hash((self.obj, self.name)) def __call__(self, *args, **kw): """ Asynchronously invoke a remote method. """ return self.obj.broker._sendMessage('',self.obj.perspective, self.obj.luid, self.name, args, kw) class PBConnectionLost(Exception): pass class IPerspective(Interface): """ per*spec*tive, n. : The relationship of aspects of a subject to each other and to a whole: 'a perspective of history'; 'a need to view the problem in the proper perspective'. This is a Perspective Broker-specific wrapper for an avatar. That is to say, a PB-published view on to the business logic for the system's concept of a 'user'. The concept of attached/detached is no longer implemented by the framework. The realm is expected to implement such semantics if needed. """ def perspectiveMessageReceived(broker, message, args, kwargs): """ This method is called when a network message is received. @arg broker: The Perspective Broker. @type message: str @arg message: The name of the method called by the other end. @type args: list in jelly format @arg args: The arguments that were passed by the other end. It is recommend that you use the `unserialize' method of the broker to decode this. @type kwargs: dict in jelly format @arg kwargs: The keyword arguments that were passed by the other end. It is recommended that you use the `unserialize' method of the broker to decode this. @rtype: A jelly list. @return: It is recommended that you use the `serialize' method of the broker on whatever object you need to return to generate the return value. """ class Avatar: """ A default IPerspective implementor. This class is intended to be subclassed, and a realm should return an instance of such a subclass when IPerspective is requested of it. A peer requesting a perspective will receive only a L{RemoteReference} to a pb.Avatar. When a method is called on that L{RemoteReference}, it will translate to a method on the remote perspective named 'perspective_methodname'. (For more information on invoking methods on other objects, see L{flavors.ViewPoint}.) """ implements(IPerspective) def perspectiveMessageReceived(self, broker, message, args, kw): """ This method is called when a network message is received. This will call:: self.perspective_%(message)s(*broker.unserialize(args), **broker.unserialize(kw)) to handle the method; subclasses of Avatar are expected to implement methods using this naming convention. """ args = broker.unserialize(args, self) kw = broker.unserialize(kw, self) method = getattr(self, "perspective_%s" % message) try: state = method(*args, **kw) except TypeError: log.msg("%s didn't accept %s and %s" % (method, args, kw)) raise return broker.serialize(state, self, method, args, kw) class AsReferenceable(Referenceable): """ A reference directed towards another object. """ def __init__(self, object, messageType="remote"): self.remoteMessageReceived = getattr( object, messageType + "MessageReceived") class RemoteReference(Serializable, styles.Ephemeral): """ A translucent reference to a remote object. I may be a reference to a L{flavors.ViewPoint}, a L{flavors.Referenceable}, or an L{IPerspective} implementor (e.g., pb.Avatar). From the client's perspective, it is not possible to tell which except by convention. I am a \"translucent\" reference because although no additional bookkeeping overhead is given to the application programmer for manipulating a reference, return values are asynchronous. See also L{twisted.internet.defer}. @ivar broker: The broker I am obtained through. @type broker: L{Broker} """ implements(IUnjellyable) def __init__(self, perspective, broker, luid, doRefCount): """(internal) Initialize me with a broker and a locally-unique ID. The ID is unique only to the particular Perspective Broker instance. """ self.luid = luid self.broker = broker self.doRefCount = doRefCount self.perspective = perspective self.disconnectCallbacks = [] def notifyOnDisconnect(self, callback): """Register a callback to be called if our broker gets disconnected. This callback will be called with one argument, this instance. """ assert callable(callback) self.disconnectCallbacks.append(callback) if len(self.disconnectCallbacks) == 1: self.broker.notifyOnDisconnect(self._disconnected) def dontNotifyOnDisconnect(self, callback): """Remove a callback that was registered with notifyOnDisconnect.""" self.disconnectCallbacks.remove(callback) if not self.disconnectCallbacks: self.broker.dontNotifyOnDisconnect(self._disconnected) def _disconnected(self): """Called if we are disconnected and have callbacks registered.""" for callback in self.disconnectCallbacks: callback(self) self.disconnectCallbacks = None def jellyFor(self, jellier): """If I am being sent back to where I came from, serialize as a local backreference. """ if jellier.invoker: assert self.broker == jellier.invoker, "Can't send references to brokers other than their own." return "local", self.luid else: return "unpersistable", "References cannot be serialized" def unjellyFor(self, unjellier, unjellyList): self.__init__(unjellier.invoker.unserializingPerspective, unjellier.invoker, unjellyList[1], 1) return self def callRemote(self, _name, *args, **kw): """Asynchronously invoke a remote method. @type _name: C{str} @param _name: the name of the remote method to invoke @param args: arguments to serialize for the remote function @param kw: keyword arguments to serialize for the remote function. @rtype: L{twisted.internet.defer.Deferred} @returns: a Deferred which will be fired when the result of this remote call is received. """ # note that we use '_name' instead of 'name' so the user can call # remote methods with 'name' as a keyword parameter, like this: # ref.callRemote("getPeopleNamed", count=12, name="Bob") return self.broker._sendMessage('',self.perspective, self.luid, _name, args, kw) def remoteMethod(self, key): """Get a L{RemoteMethod} for this key. """ return RemoteMethod(self, key) def __cmp__(self,other): """Compare me [to another L{RemoteReference}]. """ if isinstance(other, RemoteReference): if other.broker == self.broker: return cmp(self.luid, other.luid) return cmp(self.broker, other) def __hash__(self): """Hash me. """ return self.luid def __del__(self): """Do distributed reference counting on finalization. """ if self.doRefCount: self.broker.sendDecRef(self.luid) setUnjellyableForClass("remote", RemoteReference) class Local: """(internal) A reference to a local object. """ def __init__(self, object, perspective=None): """Initialize. """ self.object = object self.perspective = perspective self.refcount = 1 def __repr__(self): return "" % (self.object, self.refcount) def incref(self): """Increment and return my reference count. """ self.refcount = self.refcount + 1 return self.refcount def decref(self): """Decrement and return my reference count. """ self.refcount = self.refcount - 1 return self.refcount ## # Failure ## class CopyableFailure(failure.Failure, Copyable): """ A L{flavors.RemoteCopy} and L{flavors.Copyable} version of L{twisted.python.failure.Failure} for serialization. """ unsafeTracebacks = 0 def getStateToCopy(self): """ Collect state related to the exception which occurred, discarding state which cannot reasonably be serialized. """ state = self.__dict__.copy() state['tb'] = None state['frames'] = [] state['stack'] = [] state['value'] = str(self.value) # Exception instance if isinstance(self.type, str): state['type'] = self.type else: state['type'] = reflect.qual(self.type) # Exception class if self.unsafeTracebacks: state['traceback'] = self.getTraceback() else: state['traceback'] = 'Traceback unavailable\n' return state class CopiedFailure(RemoteCopy, failure.Failure): """ A L{CopiedFailure} is a L{pb.RemoteCopy} of a L{failure.Failure} transfered via PB. @ivar type: The full import path of the exception class which was raised on the remote end. @type type: C{str} @ivar value: A str() representation of the remote value. @type value: L{CopiedFailure} or C{str} @ivar traceback: The remote traceback. @type traceback: C{str} """ def printTraceback(self, file=None, elideFrameworkCode=0, detail='default'): if file is None: file = log.logfile file.write("Traceback from remote host -- ") file.write(self.traceback) file.write(self.type + ": " + self.value) file.write('\n') def throwExceptionIntoGenerator(self, g): """ Throw the original exception into the given generator, preserving traceback information if available. In the case of a L{CopiedFailure} where the exception type is a string, a L{pb.RemoteError} is thrown instead. @return: The next value yielded from the generator. @raise StopIteration: If there are no more values in the generator. @raise RemoteError: The wrapped remote exception. """ return g.throw(RemoteError(self.type, self.value, self.traceback)) printBriefTraceback = printTraceback printDetailedTraceback = printTraceback setUnjellyableForClass(CopyableFailure, CopiedFailure) def failure2Copyable(fail, unsafeTracebacks=0): f = types.InstanceType(CopyableFailure, fail.__dict__) f.unsafeTracebacks = unsafeTracebacks return f class Broker(banana.Banana): """I am a broker for objects. """ version = 6 username = None factory = None def __init__(self, isClient=1, security=globalSecurity): banana.Banana.__init__(self, isClient) self.disconnected = 0 self.disconnects = [] self.failures = [] self.connects = [] self.localObjects = {} self.security = security self.pageProducers = [] self.currentRequestID = 0 self.currentLocalID = 0 self.unserializingPerspective = None # Some terms: # PUID: process unique ID; return value of id() function. type "int". # LUID: locally unique ID; an ID unique to an object mapped over this # connection. type "int" # GUID: (not used yet) globally unique ID; an ID for an object which # may be on a redirected or meta server. Type as yet undecided. # Dictionary mapping LUIDs to local objects. # set above to allow root object to be assigned before connection is made # self.localObjects = {} # Dictionary mapping PUIDs to LUIDs. self.luids = {} # Dictionary mapping LUIDs to local (remotely cached) objects. Remotely # cached means that they're objects which originate here, and were # copied remotely. self.remotelyCachedObjects = {} # Dictionary mapping PUIDs to (cached) LUIDs self.remotelyCachedLUIDs = {} # Dictionary mapping (remote) LUIDs to (locally cached) objects. self.locallyCachedObjects = {} self.waitingForAnswers = {} # Mapping from LUIDs to weakref objects with callbacks for performing # any local cleanup which may be necessary for the corresponding # object once it no longer exists. self._localCleanup = {} def resumeProducing(self): """Called when the consumer attached to me runs out of buffer. """ # Go backwards over the list so we can remove indexes from it as we go for pageridx in xrange(len(self.pageProducers)-1, -1, -1): pager = self.pageProducers[pageridx] pager.sendNextPage() if not pager.stillPaging(): del self.pageProducers[pageridx] if not self.pageProducers: self.transport.unregisterProducer() # Streaming producer methods; not necessary to implement. def pauseProducing(self): pass def stopProducing(self): pass def registerPageProducer(self, pager): self.pageProducers.append(pager) if len(self.pageProducers) == 1: self.transport.registerProducer(self, 0) def expressionReceived(self, sexp): """Evaluate an expression as it's received. """ if isinstance(sexp, types.ListType): command = sexp[0] methodName = "proto_%s" % command method = getattr(self, methodName, None) if method: method(*sexp[1:]) else: self.sendCall("didNotUnderstand", command) else: raise ProtocolError("Non-list expression received.") def proto_version(self, vnum): """Protocol message: (version version-number) Check to make sure that both ends of the protocol are speaking the same version dialect. """ if vnum != self.version: raise ProtocolError("Version Incompatibility: %s %s" % (self.version, vnum)) def sendCall(self, *exp): """Utility method to send an expression to the other side of the connection. """ self.sendEncoded(exp) def proto_didNotUnderstand(self, command): """Respond to stock 'C{didNotUnderstand}' message. Log the command that was not understood and continue. (Note: this will probably be changed to close the connection or raise an exception in the future.) """ log.msg("Didn't understand command: %r" % command) def connectionReady(self): """Initialize. Called after Banana negotiation is done. """ self.sendCall("version", self.version) for notifier in self.connects: try: notifier() except: log.deferr() self.connects = None if self.factory: # in tests we won't have factory self.factory.clientConnectionMade(self) def connectionFailed(self): # XXX should never get called anymore? check! for notifier in self.failures: try: notifier() except: log.deferr() self.failures = None waitingForAnswers = None def connectionLost(self, reason): """The connection was lost. """ self.disconnected = 1 # nuke potential circular references. self.luids = None if self.waitingForAnswers: for d in self.waitingForAnswers.values(): try: d.errback(failure.Failure(PBConnectionLost(reason))) except: log.deferr() # Assure all Cacheable.stoppedObserving are called for lobj in self.remotelyCachedObjects.values(): cacheable = lobj.object perspective = lobj.perspective try: cacheable.stoppedObserving(perspective, RemoteCacheObserver(self, cacheable, perspective)) except: log.deferr() # Loop on a copy to prevent notifiers to mixup # the list by calling dontNotifyOnDisconnect for notifier in self.disconnects[:]: try: notifier() except: log.deferr() self.disconnects = None self.waitingForAnswers = None self.localSecurity = None self.remoteSecurity = None self.remotelyCachedObjects = None self.remotelyCachedLUIDs = None self.locallyCachedObjects = None self.localObjects = None def notifyOnDisconnect(self, notifier): """Call the given callback when the Broker disconnects.""" assert callable(notifier) self.disconnects.append(notifier) def notifyOnFail(self, notifier): """Call the given callback if the Broker fails to connect.""" assert callable(notifier) self.failures.append(notifier) def notifyOnConnect(self, notifier): """Call the given callback when the Broker connects.""" assert callable(notifier) if self.connects is None: try: notifier() except: log.err() else: self.connects.append(notifier) def dontNotifyOnDisconnect(self, notifier): """Remove a callback from list of disconnect callbacks.""" try: self.disconnects.remove(notifier) except ValueError: pass def localObjectForID(self, luid): """ Get a local object for a locally unique ID. @return: An object previously stored with L{registerReference} or C{None} if there is no object which corresponds to the given identifier. """ lob = self.localObjects.get(luid) if lob is None: return return lob.object maxBrokerRefsViolations = 0 def registerReference(self, object): """Get an ID for a local object. Store a persistent reference to a local object and map its id() to a generated, session-unique ID and return that ID. """ assert object is not None puid = object.processUniqueID() luid = self.luids.get(puid) if luid is None: if len(self.localObjects) > MAX_BROKER_REFS: self.maxBrokerRefsViolations = self.maxBrokerRefsViolations + 1 if self.maxBrokerRefsViolations > 3: self.transport.loseConnection() raise Error("Maximum PB reference count exceeded. " "Goodbye.") raise Error("Maximum PB reference count exceeded.") luid = self.newLocalID() self.localObjects[luid] = Local(object) self.luids[puid] = luid else: self.localObjects[luid].incref() return luid def setNameForLocal(self, name, object): """Store a special (string) ID for this object. This is how you specify a 'base' set of objects that the remote protocol can connect to. """ assert object is not None self.localObjects[name] = Local(object) def remoteForName(self, name): """Returns an object from the remote name mapping. Note that this does not check the validity of the name, only creates a translucent reference for it. """ return RemoteReference(None, self, name, 0) def cachedRemotelyAs(self, instance, incref=0): """Returns an ID that says what this instance is cached as remotely, or C{None} if it's not. """ puid = instance.processUniqueID() luid = self.remotelyCachedLUIDs.get(puid) if (luid is not None) and (incref): self.remotelyCachedObjects[luid].incref() return luid def remotelyCachedForLUID(self, luid): """Returns an instance which is cached remotely, with this LUID. """ return self.remotelyCachedObjects[luid].object def cacheRemotely(self, instance): """ XXX""" puid = instance.processUniqueID() luid = self.newLocalID() if len(self.remotelyCachedObjects) > MAX_BROKER_REFS: self.maxBrokerRefsViolations = self.maxBrokerRefsViolations + 1 if self.maxBrokerRefsViolations > 3: self.transport.loseConnection() raise Error("Maximum PB cache count exceeded. " "Goodbye.") raise Error("Maximum PB cache count exceeded.") self.remotelyCachedLUIDs[puid] = luid # This table may not be necessary -- for now, it's to make sure that no # monkey business happens with id(instance) self.remotelyCachedObjects[luid] = Local(instance, self.serializingPerspective) return luid def cacheLocally(self, cid, instance): """(internal) Store a non-filled-out cached instance locally. """ self.locallyCachedObjects[cid] = instance def cachedLocallyAs(self, cid): instance = self.locallyCachedObjects[cid] return instance def serialize(self, object, perspective=None, method=None, args=None, kw=None): """Jelly an object according to the remote security rules for this broker. """ if isinstance(object, defer.Deferred): object.addCallbacks(self.serialize, lambda x: x, callbackKeywords={ 'perspective': perspective, 'method': method, 'args': args, 'kw': kw }) return object # XXX This call is NOT REENTRANT and testing for reentrancy is just # crazy, so it likely won't be. Don't ever write methods that call the # broker's serialize() method recursively (e.g. sending a method call # from within a getState (this causes concurrency problems anyway so # you really, really shouldn't do it)) # self.jellier = _NetJellier(self) self.serializingPerspective = perspective self.jellyMethod = method self.jellyArgs = args self.jellyKw = kw try: return jelly(object, self.security, None, self) finally: self.serializingPerspective = None self.jellyMethod = None self.jellyArgs = None self.jellyKw = None def unserialize(self, sexp, perspective = None): """Unjelly an sexp according to the local security rules for this broker. """ self.unserializingPerspective = perspective try: return unjelly(sexp, self.security, None, self) finally: self.unserializingPerspective = None def newLocalID(self): """Generate a new LUID. """ self.currentLocalID = self.currentLocalID + 1 return self.currentLocalID def newRequestID(self): """Generate a new request ID. """ self.currentRequestID = self.currentRequestID + 1 return self.currentRequestID def _sendMessage(self, prefix, perspective, objectID, message, args, kw): pbc = None pbe = None answerRequired = 1 if 'pbcallback' in kw: pbc = kw['pbcallback'] del kw['pbcallback'] if 'pberrback' in kw: pbe = kw['pberrback'] del kw['pberrback'] if 'pbanswer' in kw: assert (not pbe) and (not pbc), "You can't specify a no-answer requirement." answerRequired = kw['pbanswer'] del kw['pbanswer'] if self.disconnected: raise DeadReferenceError("Calling Stale Broker") try: netArgs = self.serialize(args, perspective=perspective, method=message) netKw = self.serialize(kw, perspective=perspective, method=message) except: return defer.fail(failure.Failure()) requestID = self.newRequestID() if answerRequired: rval = defer.Deferred() self.waitingForAnswers[requestID] = rval if pbc or pbe: log.msg('warning! using deprecated "pbcallback"') rval.addCallbacks(pbc, pbe) else: rval = None self.sendCall(prefix+"message", requestID, objectID, message, answerRequired, netArgs, netKw) return rval def proto_message(self, requestID, objectID, message, answerRequired, netArgs, netKw): self._recvMessage(self.localObjectForID, requestID, objectID, message, answerRequired, netArgs, netKw) def proto_cachemessage(self, requestID, objectID, message, answerRequired, netArgs, netKw): self._recvMessage(self.cachedLocallyAs, requestID, objectID, message, answerRequired, netArgs, netKw) def _recvMessage(self, findObjMethod, requestID, objectID, message, answerRequired, netArgs, netKw): """Received a message-send. Look up message based on object, unserialize the arguments, and invoke it with args, and send an 'answer' or 'error' response. """ try: object = findObjMethod(objectID) if object is None: raise Error("Invalid Object ID") netResult = object.remoteMessageReceived(self, message, netArgs, netKw) except Error, e: if answerRequired: # If the error is Jellyable or explicitly allowed via our # security options, send it back and let the code on the # other end deal with unjellying. If it isn't Jellyable, # wrap it in a CopyableFailure, which ensures it can be # unjellied on the other end. We have to do this because # all errors must be sent back. if isinstance(e, Jellyable) or self.security.isClassAllowed(e.__class__): self._sendError(e, requestID) else: self._sendError(CopyableFailure(e), requestID) except: if answerRequired: log.msg("Peer will receive following PB traceback:", isError=True) f = CopyableFailure() self._sendError(f, requestID) log.err() else: if answerRequired: if isinstance(netResult, defer.Deferred): args = (requestID,) netResult.addCallbacks(self._sendAnswer, self._sendFailureOrError, callbackArgs=args, errbackArgs=args) # XXX Should this be done somewhere else? else: self._sendAnswer(netResult, requestID) ## # success ## def _sendAnswer(self, netResult, requestID): """(internal) Send an answer to a previously sent message. """ self.sendCall("answer", requestID, netResult) def proto_answer(self, requestID, netResult): """(internal) Got an answer to a previously sent message. Look up the appropriate callback and call it. """ d = self.waitingForAnswers[requestID] del self.waitingForAnswers[requestID] d.callback(self.unserialize(netResult)) ## # failure ## def _sendFailureOrError(self, fail, requestID): """ Call L{_sendError} or L{_sendFailure}, depending on whether C{fail} represents an L{Error} subclass or not. """ if fail.check(Error) is None: self._sendFailure(fail, requestID) else: self._sendError(fail, requestID) def _sendFailure(self, fail, requestID): """Log error and then send it.""" log.msg("Peer will receive following PB traceback:") log.err(fail) self._sendError(fail, requestID) def _sendError(self, fail, requestID): """(internal) Send an error for a previously sent message. """ if isinstance(fail, failure.Failure): # If the failures value is jellyable or allowed through security, # send the value if (isinstance(fail.value, Jellyable) or self.security.isClassAllowed(fail.value.__class__)): fail = fail.value elif not isinstance(fail, CopyableFailure): fail = failure2Copyable(fail, self.factory.unsafeTracebacks) if isinstance(fail, CopyableFailure): fail.unsafeTracebacks = self.factory.unsafeTracebacks self.sendCall("error", requestID, self.serialize(fail)) def proto_error(self, requestID, fail): """(internal) Deal with an error. """ d = self.waitingForAnswers[requestID] del self.waitingForAnswers[requestID] d.errback(self.unserialize(fail)) ## # refcounts ## def sendDecRef(self, objectID): """(internal) Send a DECREF directive. """ self.sendCall("decref", objectID) def proto_decref(self, objectID): """(internal) Decrement the reference count of an object. If the reference count is zero, it will free the reference to this object. """ refs = self.localObjects[objectID].decref() if refs == 0: puid = self.localObjects[objectID].object.processUniqueID() del self.luids[puid] del self.localObjects[objectID] self._localCleanup.pop(puid, lambda: None)() ## # caching ## def decCacheRef(self, objectID): """(internal) Send a DECACHE directive. """ self.sendCall("decache", objectID) def proto_decache(self, objectID): """(internal) Decrement the reference count of a cached object. If the reference count is zero, free the reference, then send an 'uncached' directive. """ refs = self.remotelyCachedObjects[objectID].decref() # log.msg('decaching: %s #refs: %s' % (objectID, refs)) if refs == 0: lobj = self.remotelyCachedObjects[objectID] cacheable = lobj.object perspective = lobj.perspective # TODO: force_decache needs to be able to force-invalidate a # cacheable reference. try: cacheable.stoppedObserving(perspective, RemoteCacheObserver(self, cacheable, perspective)) except: log.deferr() puid = cacheable.processUniqueID() del self.remotelyCachedLUIDs[puid] del self.remotelyCachedObjects[objectID] self.sendCall("uncache", objectID) def proto_uncache(self, objectID): """(internal) Tell the client it is now OK to uncache an object. """ # log.msg("uncaching locally %d" % objectID) obj = self.locallyCachedObjects[objectID] obj.broker = None ## def reallyDel(obj=obj): ## obj.__really_del__() ## obj.__del__ = reallyDel del self.locallyCachedObjects[objectID] def respond(challenge, password): """Respond to a challenge. This is useful for challenge/response authentication. """ m = md5() m.update(password) hashedPassword = m.digest() m = md5() m.update(hashedPassword) m.update(challenge) doubleHashedPassword = m.digest() return doubleHashedPassword def challenge(): """I return some random data.""" crap = '' for x in range(random.randrange(15,25)): crap = crap + chr(random.randint(65,90)) crap = md5(crap).digest() return crap class PBClientFactory(protocol.ClientFactory): """ Client factory for PB brokers. As with all client factories, use with reactor.connectTCP/SSL/etc.. getPerspective and getRootObject can be called either before or after the connect. """ protocol = Broker unsafeTracebacks = False def __init__(self, unsafeTracebacks=False, security=globalSecurity): """ @param unsafeTracebacks: if set, tracebacks for exceptions will be sent over the wire. @type unsafeTracebacks: C{bool} @param security: security options used by the broker, default to C{globalSecurity}. @type security: L{twisted.spread.jelly.SecurityOptions} """ self.unsafeTracebacks = unsafeTracebacks self.security = security self._reset() def buildProtocol(self, addr): """ Build the broker instance, passing the security options to it. """ p = self.protocol(isClient=True, security=self.security) p.factory = self return p def _reset(self): self.rootObjectRequests = [] # list of deferred self._broker = None self._root = None def _failAll(self, reason): deferreds = self.rootObjectRequests self._reset() for d in deferreds: d.errback(reason) def clientConnectionFailed(self, connector, reason): self._failAll(reason) def clientConnectionLost(self, connector, reason, reconnecting=0): """Reconnecting subclasses should call with reconnecting=1.""" if reconnecting: # any pending requests will go to next connection attempt # so we don't fail them. self._broker = None self._root = None else: self._failAll(reason) def clientConnectionMade(self, broker): self._broker = broker self._root = broker.remoteForName("root") ds = self.rootObjectRequests self.rootObjectRequests = [] for d in ds: d.callback(self._root) def getRootObject(self): """Get root object of remote PB server. @return: Deferred of the root object. """ if self._broker and not self._broker.disconnected: return defer.succeed(self._root) d = defer.Deferred() self.rootObjectRequests.append(d) return d def disconnect(self): """If the factory is connected, close the connection. Note that if you set up the factory to reconnect, you will need to implement extra logic to prevent automatic reconnection after this is called. """ if self._broker: self._broker.transport.loseConnection() def _cbSendUsername(self, root, username, password, client): return root.callRemote("login", username).addCallback( self._cbResponse, password, client) def _cbResponse(self, (challenge, challenger), password, client): return challenger.callRemote("respond", respond(challenge, password), client) def _cbLoginAnonymous(self, root, client): """ Attempt an anonymous login on the given remote root object. @type root: L{RemoteReference} @param root: The object on which to attempt the login, most likely returned by a call to L{PBClientFactory.getRootObject}. @param client: A jellyable object which will be used as the I{mind} parameter for the login attempt. @rtype: L{Deferred} @return: A L{Deferred} which will be called back with a L{RemoteReference} to an avatar when anonymous login succeeds, or which will errback if anonymous login fails. """ return root.callRemote("loginAnonymous", client) def login(self, credentials, client=None): """ Login and get perspective from remote PB server. Currently the following credentials are supported:: L{twisted.cred.credentials.IUsernamePassword} L{twisted.cred.credentials.IAnonymous} @rtype: L{Deferred} @return: A L{Deferred} which will be called back with a L{RemoteReference} for the avatar logged in to, or which will errback if login fails. """ d = self.getRootObject() if IAnonymous.providedBy(credentials): d.addCallback(self._cbLoginAnonymous, client) else: d.addCallback( self._cbSendUsername, credentials.username, credentials.password, client) return d class PBServerFactory(protocol.ServerFactory): """ Server factory for perspective broker. Login is done using a Portal object, whose realm is expected to return avatars implementing IPerspective. The credential checkers in the portal should accept IUsernameHashedPassword or IUsernameMD5Password. Alternatively, any object providing or adaptable to L{IPBRoot} can be used instead of a portal to provide the root object of the PB server. """ unsafeTracebacks = False # object broker factory protocol = Broker def __init__(self, root, unsafeTracebacks=False, security=globalSecurity): """ @param root: factory providing the root Referenceable used by the broker. @type root: object providing or adaptable to L{IPBRoot}. @param unsafeTracebacks: if set, tracebacks for exceptions will be sent over the wire. @type unsafeTracebacks: C{bool} @param security: security options used by the broker, default to C{globalSecurity}. @type security: L{twisted.spread.jelly.SecurityOptions} """ self.root = IPBRoot(root) self.unsafeTracebacks = unsafeTracebacks self.security = security def buildProtocol(self, addr): """ Return a Broker attached to the factory (as the service provider). """ proto = self.protocol(isClient=False, security=self.security) proto.factory = self proto.setNameForLocal("root", self.root.rootObject(proto)) return proto def clientConnectionMade(self, protocol): # XXX does this method make any sense? pass class IUsernameMD5Password(ICredentials): """ I encapsulate a username and a hashed password. This credential is used for username/password over PB. CredentialCheckers which check this kind of credential must store the passwords in plaintext form or as a MD5 digest. @type username: C{str} or C{Deferred} @ivar username: The username associated with these credentials. """ def checkPassword(password): """ Validate these credentials against the correct password. @type password: C{str} @param password: The correct, plaintext password against which to check. @rtype: C{bool} or L{Deferred} @return: C{True} if the credentials represented by this object match the given password, C{False} if they do not, or a L{Deferred} which will be called back with one of these values. """ def checkMD5Password(password): """ Validate these credentials against the correct MD5 digest of the password. @type password: C{str} @param password: The correct MD5 digest of a password against which to check. @rtype: C{bool} or L{Deferred} @return: C{True} if the credentials represented by this object match the given digest, C{False} if they do not, or a L{Deferred} which will be called back with one of these values. """ class _PortalRoot: """Root object, used to login to portal.""" implements(IPBRoot) def __init__(self, portal): self.portal = portal def rootObject(self, broker): return _PortalWrapper(self.portal, broker) registerAdapter(_PortalRoot, Portal, IPBRoot) class _JellyableAvatarMixin: """ Helper class for code which deals with avatars which PB must be capable of sending to a peer. """ def _cbLogin(self, (interface, avatar, logout)): """ Ensure that the avatar to be returned to the client is jellyable and set up disconnection notification to call the realm's logout object. """ if not IJellyable.providedBy(avatar): avatar = AsReferenceable(avatar, "perspective") puid = avatar.processUniqueID() # only call logout once, whether the connection is dropped (disconnect) # or a logout occurs (cleanup), and be careful to drop the reference to # it in either case logout = [ logout ] def maybeLogout(): if not logout: return fn = logout[0] del logout[0] fn() self.broker._localCleanup[puid] = maybeLogout self.broker.notifyOnDisconnect(maybeLogout) return avatar class _PortalWrapper(Referenceable, _JellyableAvatarMixin): """ Root Referenceable object, used to login to portal. """ def __init__(self, portal, broker): self.portal = portal self.broker = broker def remote_login(self, username): """ Start of username/password login. """ c = challenge() return c, _PortalAuthChallenger(self.portal, self.broker, username, c) def remote_loginAnonymous(self, mind): """ Attempt an anonymous login. @param mind: An object to use as the mind parameter to the portal login call (possibly None). @rtype: L{Deferred} @return: A Deferred which will be called back with an avatar when login succeeds or which will be errbacked if login fails somehow. """ d = self.portal.login(Anonymous(), mind, IPerspective) d.addCallback(self._cbLogin) return d class _PortalAuthChallenger(Referenceable, _JellyableAvatarMixin): """ Called with response to password challenge. """ implements(IUsernameHashedPassword, IUsernameMD5Password) def __init__(self, portal, broker, username, challenge): self.portal = portal self.broker = broker self.username = username self.challenge = challenge def remote_respond(self, response, mind): self.response = response d = self.portal.login(self, mind, IPerspective) d.addCallback(self._cbLogin) return d # IUsernameHashedPassword: def checkPassword(self, password): return self.checkMD5Password(md5(password).digest()) # IUsernameMD5Password def checkMD5Password(self, md5Password): md = md5() md.update(md5Password) md.update(self.challenge) correct = md.digest() return self.response == correct __all__ = [ # Everything from flavors is exposed publically here. 'IPBRoot', 'Serializable', 'Referenceable', 'NoSuchMethod', 'Root', 'ViewPoint', 'Viewable', 'Copyable', 'Jellyable', 'Cacheable', 'RemoteCopy', 'RemoteCache', 'RemoteCacheObserver', 'copyTags', 'setUnjellyableForClass', 'setUnjellyableFactoryForClass', 'setUnjellyableForClassTree', 'setCopierForClass', 'setFactoryForClass', 'setCopierForClassTree', 'MAX_BROKER_REFS', 'portno', 'ProtocolError', 'DeadReferenceError', 'Error', 'PBConnectionLost', 'RemoteMethod', 'IPerspective', 'Avatar', 'AsReferenceable', 'RemoteReference', 'CopyableFailure', 'CopiedFailure', 'failure2Copyable', 'Broker', 'respond', 'challenge', 'PBClientFactory', 'PBServerFactory', 'IUsernameMD5Password', ]