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# -*- test-case-name: twisted.spread.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 similarly, 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
from hashlib import md5
from zope.interface import Interface, implementer
from twisted.cred.credentials import (
Anonymous,
IAnonymous,
ICredentials,
IUsernameHashedPassword,
)
from twisted.cred.portal import Portal
from twisted.internet import defer, protocol
from twisted.persisted import styles
# Twisted Imports
from twisted.python import failure, log, reflect
from twisted.python.compat import cmp, comparable
from twisted.python.components import registerAdapter
from twisted.spread import banana
# These three are backwards compatibility aliases for the previous three.
# Ultimately they should be deprecated. -exarkun
from twisted.spread.flavors import (
Cacheable,
Copyable,
IPBRoot,
Jellyable,
NoSuchMethod,
Referenceable,
RemoteCache,
RemoteCacheObserver,
RemoteCopy,
Root,
Serializable,
Viewable,
ViewPoint,
copyTags,
setCopierForClass,
setCopierForClassTree,
setFactoryForClass,
setUnjellyableFactoryForClass,
setUnjellyableForClass,
setUnjellyableForClassTree,
)
from twisted.spread.interfaces import IJellyable, IUnjellyable
from twisted.spread.jelly import _newInstance, globalSecurity, jelly, unjelly
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
@comparable
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(
b"",
self.obj.perspective,
self.obj.luid,
self.name.encode("utf-8"),
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.
"""
@implementer(IPerspective)
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}.)
"""
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(f"{method} didn't accept {args} and {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")
@implementer(IUnjellyable)
@comparable
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} implementer (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}
"""
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.
@param callback: a callable which 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.
@param callback: a callable
"""
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 b"local", self.luid
else:
return b"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: L{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.
"""
if not isinstance(_name, bytes):
_name = _name.encode("utf8")
# 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(
b"", self.perspective, self.luid, _name, args, kw
)
def remoteMethod(self, key):
"""
@param key: The key.
@return: A L{RemoteMethod} for this key.
"""
return RemoteMethod(self, key)
def __cmp__(self, other):
"""
@param other: another L{RemoteReference} to compare me to.
"""
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) -> str:
return f"<pb.Local {self.object!r} ref:{self.refcount}>"
def incref(self):
"""
Increment the reference count.
@return: the reference count after incrementing
"""
self.refcount = self.refcount + 1
return self.refcount
def decref(self):
"""
Decrement the reference count.
@return: the reference count after decrementing
"""
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, bytes):
state["type"] = self.type
else:
state["type"] = reflect.qual(self.type).encode("utf-8") # 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}
transferred 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
failureType = self.type
if not isinstance(failureType, str):
failureType = failureType.decode("utf-8")
file.write("Traceback from remote host -- ")
file.write(failureType + ": " + 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 = _newInstance(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 range(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()
def pauseProducing(self):
# Streaming producer method; not necessary to implement.
pass
def stopProducing(self):
# Streaming producer method; not necessary to implement.
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, list):
command = sexp[0]
if not isinstance(command, str):
command = command.decode("utf8")
methodName = "proto_%s" % command
method = getattr(self, methodName, None)
if method:
method(*sexp[1:])
else:
self.sendCall(b"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.
@param vnum: The version number.
"""
if vnum != self.version:
raise ProtocolError(f"Version Incompatibility: {self.version} {vnum}")
def sendCall(self, *exp):
"""
Utility method to send an expression to the other side of the connection.
@param exp: The expression.
"""
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.)
@param command: The command to log.
"""
log.msg("Didn't understand command: %r" % command)
def connectionReady(self):
"""
Initialize. Called after Banana negotiation is done.
"""
self.sendCall(b"version", self.version)
for notifier in self.connects:
try:
notifier()
except BaseException:
log.deferr()
self.connects = None
self.factory.clientConnectionMade(self)
def connectionFailed(self):
# XXX should never get called anymore? check!
for notifier in self.failures:
try:
notifier()
except BaseException:
log.deferr()
self.failures = None
waitingForAnswers = None
def connectionLost(self, reason):
"""
The connection was lost.
@param reason: message to put in L{failure.Failure}
"""
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 BaseException:
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 BaseException:
log.deferr()
# Loop on a copy to prevent notifiers to mixup
# the list by calling dontNotifyOnDisconnect
for notifier in self.disconnects[:]:
try:
notifier()
except BaseException:
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):
"""
@param notifier: callback to call when the Broker disconnects.
"""
assert callable(notifier)
self.disconnects.append(notifier)
def notifyOnFail(self, notifier):
"""
@param notifier: callback to call if the Broker fails to connect.
"""
assert callable(notifier)
self.failures.append(notifier)
def notifyOnConnect(self, notifier):
"""
@param notifier: callback to call when the Broker connects.
"""
assert callable(notifier)
if self.connects is None:
try:
notifier()
except BaseException:
log.err()
else:
self.connects.append(notifier)
def dontNotifyOnDisconnect(self, notifier):
"""
@param notifier: callback to remove 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
L{None} if there is no object which corresponds to the given
identifier.
"""
if isinstance(luid, str):
luid = luid.encode("utf8")
lob = self.localObjects.get(luid)
if lob is None:
return
return lob.object
maxBrokerRefsViolations = 0
def registerReference(self, object):
"""
Store a persistent reference to a local object and map its
id() to a generated, session-unique ID.
@param object: a local object
@return: the generated 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.
@param name: An ID.
@param object: The object.
"""
if isinstance(name, str):
name = name.encode("utf8")
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.
@param name: The name to look up.
@return: An object which maps to the name.
"""
if isinstance(name, str):
name = name.encode("utf8")
return RemoteReference(None, self, name, 0)
def cachedRemotelyAs(self, instance, incref=0):
"""
@param instance: The instance to look up.
@param incref: Flag to specify whether to increment the
reference.
@return: An ID that says what this instance is cached as
remotely, or L{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):
"""
@param luid: The LUID to look up.
@return: An instance which is cached remotely.
"""
return self.remotelyCachedObjects[luid].object
def cacheRemotely(self, instance):
"""
XXX
@return: A new LUID.
"""
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.
@param object: The object to jelly.
@param perspective: The perspective.
@param method: The method.
@param args: Arguments.
@param kw: Keyword arguments.
"""
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.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.
@param sexp: The object to unjelly.
@param perspective: The perspective.
"""
self.unserializingPerspective = perspective
try:
return unjelly(sexp, self.security, None, self)
finally:
self.unserializingPerspective = None
def newLocalID(self):
"""
@return: A newly generated LUID.
"""
self.currentLocalID = self.currentLocalID + 1
return self.currentLocalID
def newRequestID(self):
"""
@return: A newly generated 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 BaseException:
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 + b"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.
@param findObjMethod: A callable which takes C{objectID} as argument.
@param requestID: The requiest ID.
@param objectID: The object ID.
@param message: The message.
@param answerRequired:
@param netArgs: Arguments.
@param netKw: Keyword arguments.
"""
if not isinstance(message, str):
message = message.decode("utf8")
try:
object = findObjMethod(objectID)
if object is None:
raise Error("Invalid Object ID")
netResult = object.remoteMessageReceived(self, message, netArgs, netKw)
except Error as 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 BaseException:
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)
def _sendAnswer(self, netResult, requestID):
"""
(internal) Send an answer to a previously sent message.
@param netResult: The answer.
@param requestID: The request ID.
"""
self.sendCall(b"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.
@param requestID: The request ID.
@param netResult: The answer.
"""
d = self.waitingForAnswers[requestID]
del self.waitingForAnswers[requestID]
d.callback(self.unserialize(netResult))
def _sendFailureOrError(self, fail, requestID):
"""
Call L{_sendError} or L{_sendFailure}, depending on whether C{fail}
represents an L{Error} subclass or not.
@param fail: The failure.
@param requestID: The request ID.
"""
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.
@param fail: The failure.
@param requestID: The request ID.
"""
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.
@param fail: The failure.
@param requestID: The request ID.
"""
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(b"error", requestID, self.serialize(fail))
def proto_error(self, requestID, fail):
"""
(internal) Deal with an error.
@param requestID: The request ID.
@param fail: The failure.
"""
d = self.waitingForAnswers[requestID]
del self.waitingForAnswers[requestID]
d.errback(self.unserialize(fail))
def sendDecRef(self, objectID):
"""
(internal) Send a DECREF directive.
@param objectID: The object ID.
"""
self.sendCall(b"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.
@param objectID: The object ID.
"""
if isinstance(objectID, str):
objectID = objectID.encode("utf8")
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)()
def decCacheRef(self, objectID):
"""
(internal) Send a DECACHE directive.
@param objectID: The object ID.
"""
self.sendCall(b"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.
@param objectID: The object ID.
"""
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 BaseException:
log.deferr()
puid = cacheable.processUniqueID()
del self.remotelyCachedLUIDs[puid]
del self.remotelyCachedObjects[objectID]
self.sendCall(b"uncache", objectID)
def proto_uncache(self, objectID):
"""
(internal) Tell the client it is now OK to uncache an object.
@param objectID: The object ID.
"""
# 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.
@param challenge: A challenge.
@param password: A password.
@return: The password hashed twice.
"""
m = md5()
m.update(password)
hashedPassword = m.digest()
m = md5()
m.update(hashedPassword)
m.update(challenge)
doubleHashedPassword = m.digest()
return doubleHashedPassword
def challenge():
"""
@return: Some random data.
"""
crap = bytes(random.randint(65, 90) for x in range(random.randrange(15, 25)))
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, challenges, password, client):
challenge, challenger = challenges
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.
"""
@implementer(IPBRoot)
class _PortalRoot:
"""
Root object, used to login to portal.
"""
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, result):
"""
Ensure that the avatar to be returned to the client is jellyable and
set up disconnection notification to call the realm's logout object.
"""
(interface, avatar, logout) = result
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.
@param username: The username.
"""
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
@implementer(IUsernameHashedPassword, IUsernameMD5Password)
class _PortalAuthChallenger(Referenceable, _JellyableAvatarMixin):
"""
Called with response to password challenge.
"""
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
def checkPassword(self, password):
"""
L{IUsernameHashedPassword}
@param password: The password.
@return: L{_PortalAuthChallenger.checkMD5Password}
"""
return self.checkMD5Password(md5(password).digest())
def checkMD5Password(self, md5Password):
"""
L{IUsernameMD5Password}
@param md5Password:
@rtype: L{bool}
@return: L{True} if password matches.
"""
md = md5()
md.update(md5Password)
md.update(self.challenge)
correct = md.digest()
return self.response == correct
__all__ = [
# Everything from flavors is exposed publicly 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",
]