"""
Persistent references for PB.
Maintainer: U{Glyph Lefkowitz<mailto:glyph@twistedmatrix.com>}
Stability: in flux
Future Plans: PerspectiveConnector should be made obsolete by PB URLs. It
should be very easy to replace when that new functionality is available.
"""
from twisted.spread import pb
from twisted.internet import defer
from twisted.python import log
True = 1
False = 0
class PerspectiveConnector:
def __init__(self, host, port, username, password, serviceName,
perspectiveName=None, client=None):
self.host = host
self.port = port
self.username = username
self.password = password
self.serviceName = serviceName
self.perspectiveName = perspectiveName
self.client = client
self.reference = None
self.connecting = False
self.methodsToCall = []
def __getstate__(self):
d = self.__dict__.copy()
d['reference'] = None
d['connecting'] = False
d['methodsToCall'] = []
return d
def _cbConnected(self, reference):
"""We've connected. Reset everything and call all pending methods.
"""
log.msg( 'connected!' )
self.reference = reference
self.connecting = False
for method, args, kw, defr in self.methodsToCall:
apply(reference.callRemote, (method,)+args, kw).addCallbacks(
defr.callback,
defr.errback)
self.methodsToCall = []
def _ebConnected(self, error):
"""We haven't connected yet. Try again.
"""
log.msg( 'PerspectiveConnector: error in connecting: %s' % error)
self.startConnecting()
def startConnecting(self):
log.msg( 'PerspectiveConnector: connecting: %s:%s %s/%s/%s' % (self.host, self.port, self.serviceName, self.username, self.perspectiveName))
return pb.connect(self.host, self.port, self.username, self.password,
self.serviceName, self.perspectiveName, self.client
).addCallbacks(self._cbConnected, self._ebConnected)
def callRemote(self, method, *args, **kw):
if self.reference:
try:
return apply(self.reference.callRemote, (method,)+args, kw)
except pb.DeadReferenceError:
log.msg("Calling dead reference; trying to reconnect.")
self.reference = None
if not self.connecting:
self.startConnecting()
self.connecting = True
defr = defer.Deferred()
self.methodsToCall.append((method, args, kw, defr))
return defr