"""Standard implementations of Twisted protocol-related interfaces.
Start here if you are looking to write a new protocol implementation for
Twisted. The Protocol class contains some introductory material.
API Stability: stable, other than ClientCreator.
Maintainer: U{Itamar Shtull-Trauring<mailto:twisted@itamarst.org>}
"""
import random
from twisted.python import log, failure
from twisted.internet import interfaces, error, defer
class Factory:
"""This is a factory which produces protocols.
By default, buildProtocol will create a protocol of the class given in
self.protocol.
"""
__implements__ = (interfaces.IProtocolFactory,)
protocol = None
numPorts = 0
noisy = "sure, why not"
def doStart(self):
"""Make sure startFactory is called."""
if not self.numPorts:
if self.noisy:
log.msg("Starting factory %s" % self)
self.startFactory()
self.numPorts = self.numPorts + 1
def doStop(self):
"""Make sure stopFactory is called."""
assert self.numPorts > 0
self.numPorts = self.numPorts - 1
if not self.numPorts:
if self.noisy:
log.msg("Stopping factory %s" % self)
self.stopFactory()
def startFactory(self):
"""This will be called before I begin listening on a Port or Connector.
It will only be called once, even if the factory is connected
to multiple ports.
This can be used to perform 'unserialization' tasks that
are best put off until things are actually running, such
as connecting to a database, opening files, etcetera.
"""
def stopFactory(self):
"""This will be called before I stop listening on all Ports/Connectors.
This can be used to perform 'shutdown' tasks such as disconnecting
database connections, closing files, etc.
It will be called, for example, before an application shuts down,
if it was connected to a port.
"""
def buildProtocol(self, addr):
"""Create an instance of a subclass of Protocol.
The returned instance will handle input on an incoming server
connection, and an attribute \"factory\" pointing to the creating
factory.
Override this method to alter how Protocol instances get created.
@param addr: an object implementing L{twisted.internet.interfaces.IAddress}
"""
p = self.protocol()
p.factory = self
return p
class ClientFactory(Factory):
"""A Protocol factory for clients.
This can be used together with the various connectXXX methods in
reactors.
"""
def startedConnecting(self, connector):
"""Called when a connection has been started.
You can call connector.stopConnecting() to stop the connection attempt.
@param connector: a Connector object.
"""
def clientConnectionFailed(self, connector, reason):
"""Called when a connection has failed to connect.
It may be useful to call connector.connect() - this will reconnect.
@type reason: L{twisted.python.failure.Failure}
"""
def clientConnectionLost(self, connector, reason):
"""Called when an established connection is lost.
It may be useful to call connector.connect() - this will reconnect.
@type reason: L{twisted.python.failure.Failure}
"""
class _InstanceFactory(ClientFactory):
"""Factory used by ClientCreator."""
def __init__(self, reactor, instance, deferred):
self.reactor = reactor
self.instance = instance
self.deferred = deferred
def buildProtocol(self, addr):
self.reactor.callLater(0, self.deferred.callback, self.instance)
return self.instance
def clientConnectionFailed(self, connector, reason):
self.reactor.callLater(0, self.deferred.errback, reason)
class ClientCreator:
"""Useful for cases when we don't really need a factory.
Mainly this is when there is no shared state between protocol instances
(e.g. protocols that work in a way similar to httplib or smtplib).
The API for this class is not stable.
"""
def __init__(self, reactor, protocolClass, *args, **kwargs):
self.reactor = reactor
self.protocolClass = protocolClass
self.args = args
self.kwargs = kwargs
def connectTCP(self, host, port, timeout=30, bindAddress=None):
"""Connect to remote host, return Deferred of resulting protocol instance."""
d = defer.Deferred()
f = _InstanceFactory(self.reactor, self.protocolClass(*self.args, **self.kwargs), d)
self.reactor.connectTCP(host, port, f, timeout=timeout, bindAddress=bindAddress)
return d
def connectUNIX(self, address, timeout = 30):
d = defer.Deferred()
f = _InstanceFactory(self.reactor, self.protocolClass(*self.args, **self.kwargs), d)
self.reactor.connectUNIX(address, f, timeout = timeout)
return d
class ReconnectingClientFactory(ClientFactory):
"""My clients auto-reconnect with an exponential back-off.
Note that clients should call my resetDelay method after they have
connected successfully.
@ivar maxDelay: Maximum number of seconds between connection attempts.
@ivar initialDelay: Delay for the first reconnection attempt.
@ivar factor: a multiplicitive factor by which the delay grows
@ivar jitter: percentage of randomness to introduce into the delay length
to prevent stampeding.
"""
maxDelay = 3600
initialDelay = 1.0
factor = 2.7182818284590451 jitter = 0.11962656492
delay = initialDelay
retries = 0
maxRetries = None
_callID = None
connector = None
continueTrying = 1
def clientConnectionFailed(self, connector, reason):
if self.continueTrying:
self.connector = connector
if not reason.check(error.UserError):
self.retry()
def clientConnectionLost(self, connector, unused_reason):
if self.continueTrying:
self.connector = connector
self.retry()
def retry(self, connector=None):
"""Have this connector connect again, after a suitable delay.
"""
if not self.continueTrying:
log.msg("Abandoning %s on explicit request" % (connector,))
return
if connector is None:
if self.connector is None:
raise ValueError("no connector to retry")
else:
connector = self.connector
self.retries += 1
if self.maxRetries is not None and (self.retries > self.maxRetries):
log.msg("Abandoning %s after %d retries." %
(connector, self.retries))
return
self.delay = min(self.delay * self.factor, self.maxDelay)
if self.jitter:
self.delay = random.normalvariate(self.delay,
self.delay * self.jitter)
log.msg("%s will retry in %d seconds" % (connector, self.delay,))
from twisted.internet import reactor
def reconnector():
self._callID = None
connector.connect()
self._callID = reactor.callLater(self.delay, reconnector)
def stopTrying(self):
"""I put a stop to any attempt to reconnect in progress.
"""
if self._callID:
self._callID.cancel()
self._callID = None
if self.connector:
try:
self.connector.stopConnecting()
except error.NotConnectingError:
pass
self.continueTrying = 0
def resetDelay(self):
"""Call me after a successful connection to reset.
I reset the delay and the retry counter.
"""
self.delay = self.initialDelay
self.retries = 0
self._callID = None
self.continueTrying = 1
class ServerFactory(Factory):
"""Subclass this to indicate that your protocol.Factory is only usable for servers.
"""
class BaseProtocol:
"""This is the abstract superclass of all protocols.
If you are going to write a new protocol for Twisted, start here. The
docstrings of this class explain how you can get started. Any protocol
implementation, either client or server, should be a subclass of me.
My API is quite simple. Implement dataReceived(data) to handle both
event-based and synchronous input; output can be sent through the
'transport' attribute, which is to be an instance that implements
L{twisted.internet.interfaces.ITransport}.
Some subclasses exist already to help you write common types of protocols:
see the L{twisted.protocols.basic} module for a few of them.
"""
connected = 0
transport = None
def makeConnection(self, transport):
"""Make a connection to a transport and a server.
This sets the 'transport' attribute of this Protocol, and calls the
connectionMade() callback.
"""
self.connected = 1
self.transport = transport
self.connectionMade()
def connectionMade(self):
"""Called when a connection is made.
This may be considered the initializer of the protocol, because
it is called when the connection is completed. For clients,
this is called once the connection to the server has been
established; for servers, this is called after an accept() call
stops blocking and a socket has been received. If you need to
send any greeting or initial message, do it here.
"""
connectionDone=failure.Failure(error.ConnectionDone())
connectionDone.cleanFailure()
class Protocol(BaseProtocol):
__implements__ = (interfaces.IProtocol,)
def dataReceived(self, data):
"""Called whenever data is received.
Use this method to translate to a higher-level message. Usually, some
callback will be made upon the receipt of each complete protocol
message.
@param data: a string of indeterminate length. Please keep in mind
that you will probably need to buffer some data, as partial
(or multiple) protocol messages may be received! I recommend
that unit tests for protocols call through to this method with
differing chunk sizes, down to one byte at a time.
"""
def connectionLost(self, reason=connectionDone):
"""Called when the connection is shut down.
Clear any circular references here, and any external references
to this Protocol. The connection has been closed.
@type reason: L{twisted.python.failure.Failure}
"""
def connectionFailed(self):
"""(Deprecated)
This used to be called when the connection was not properly
established.
"""
import warnings
warnings.warn("connectionFailed is deprecated. See new Client API",
category=DeprecationWarning, stacklevel=2)
from twisted.python import components
class ProtocolToConsumerAdapter(components.Adapter):
"""
This class is unstable.
"""
__implements__ = interfaces.IConsumer
def write(self, data):
self.original.dataReceived(data)
def registerProducer(self, producer, streaming):
pass
def unregisterProducer(self):
pass
components.registerAdapter(ProtocolToConsumerAdapter, interfaces.IProtocol,
interfaces.IConsumer)
class ConsumerToProtocolAdapter(components.Adapter):
"""
This class is unstable.
"""
__implements__ = interfaces.IProtocol
def dataReceived(self, data):
self.original.write(data)
def connectionLost(self, reason):
pass
def makeConnection(self, transport):
pass
def connectionMade(self):
pass
components.registerAdapter(ConsumerToProtocolAdapter, interfaces.IConsumer,
interfaces.IProtocol)
class ProcessProtocol(BaseProtocol):
"""Processes have some additional methods besides receiving data.
"""
def childDataReceived(self, childFD, data):
if childFD == 1:
self.outReceived(data)
elif childFD == 2:
self.errReceived(data)
def outReceived(self, data):
"""Some data was received from stdout."""
def errReceived(self, data):
"""Some data was received from stderr."""
def childConnectionLost(self, childFD):
if childFD == 0:
self.inConnectionLost()
elif childFD == 1:
self.outConnectionLost()
elif childFD == 2:
self.errConnectionLost()
def inConnectionLost(self):
"""This will be called when stdin is closed."""
def outConnectionLost(self):
"""This will be called when stdout is closed."""
def errConnectionLost(self):
"""This will be called when stderr is closed."""
def processEnded(self, reason):
"""This will be called when the subprocess is finished.
@type reason: L{twisted.python.failure.Failure}
"""
class AbstractDatagramProtocol:
"""Abstract protocol for datagram-oriented transports, e.g. IP, ICMP, ARP, UDP."""
transport = None
numPorts = 0
noisy = True
def __getstate__(self):
d = self.__dict__.copy()
d['transport'] = None
return d
def doStart(self):
"""Make sure startProtocol is called.
This will be called by makeConnection(), users should not call it.
"""
if not self.numPorts:
if self.noisy:
log.msg("Starting protocol %s" % self)
self.startProtocol()
self.numPorts = self.numPorts + 1
def doStop(self):
"""Make sure stopProtocol is called.
This will be called by the port, users should not call it.
"""
assert self.numPorts > 0
self.numPorts = self.numPorts - 1
self.transport = None
if not self.numPorts:
if self.noisy:
log.msg("Stopping protocol %s" % self)
self.stopProtocol()
def startProtocol(self):
"""Called when a transport is connected to this protocol.
Will only be called once, even if multiple ports are connected.
"""
def stopProtocol(self):
"""Called when the transport is disconnected.
Will only be called once, after all ports are disconnected.
"""
def makeConnection(self, transport):
"""Make a connection to a transport and a server.
This sets the 'transport' attribute of this DatagramProtocol, and calls the
doStart() callback.
"""
assert self.transport == None
self.transport = transport
self.doStart()
def datagramReceived(self, datagram, addr):
"""Called when a datagram is received.
@param datagram: the string received from the transport.
@param addr: tuple of source of datagram.
"""
class DatagramProtocol(AbstractDatagramProtocol):
"""Protocol for datagram-oriented transport, e.g. UDP."""
def connectionRefused(self):
"""Called due to error from write in connected mode.
Note this is a result of ICMP message generated by *previous*
write.
"""
class ConnectedDatagramProtocol(DatagramProtocol):
"""Protocol for connected datagram-oriented transport.
No longer necessary for UDP.
"""
def datagramReceived(self, datagram):
"""Called when a datagram is received.
@param datagram: the string received from the transport.
"""
def connectionFailed(self, failure):
"""Called if connecting failed.
Usually this will be due to a DNS lookup failure.
"""
class FileWrapper:
"""A wrapper around a file-like object to make it behave as a Transport.
"""
__implements__ = interfaces.ITransport
closed = 0
disconnecting = 0
producer = None
streamingProducer = 0
def __init__(self, file):
self.file = file
def write(self, data):
try:
self.file.write(data)
except:
self.handleException()
def _checkProducer(self):
if self.producer:
self.producer.resumeProducing()
def registerProducer(self, producer, streaming):
"""From abstract.FileDescriptor
"""
self.producer = producer
self.streamingProducer = streaming
if not streaming:
producer.resumeProducing()
def unregisterProducer(self):
self.producer = None
def stopConsuming(self):
self.unregisterProducer()
self.loseConnection()
def writeSequence(self, iovec):
self.write("".join(iovec))
def loseConnection(self):
self.closed = 1
try:
self.file.close()
except (IOError, OSError):
self.handleException()
def getPeer(self):
return 'file', 'file'
def getHost(self):
return 'file'
def handleException(self):
pass
__all__ = ["Factory", "ClientFactory", "ReconnectingClientFactory",
"Protocol", "ProcessProtocol", "FileWrapper", "ServerFactory",
"DatagramProtocol", "ConnectedDatagramProtocol", "ClientCreator"]