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# Copyright (C) 2014 Nippon Telegraph and Telephone Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Module defines protocol based classes and utils.
"""
import abc
class Protocol(object, metaclass=abc.ABCMeta):
"""Interface for various protocols.
Protocol usually encloses a transport/connection/socket to
peer/client/server and encodes and decodes communication/messages. Protocol
can also maintain any related state machine, protocol message encoding or
decoding utilities. This interface identifies minimum methods to support to
facilitate or provide hooks to sub-classes to override behavior as
appropriate.
"""
@abc.abstractmethod
def data_received(self, data):
"""Handler for date received over connection/transport.
Here *data* is in raw bytes. This *data* should further be converted to
protocol specific messages and as appropriate transition to new state
machine state or send appropriate response.
"""
pass
@abc.abstractmethod
def connection_made(self):
"""Called when connection has been established according to protocol.
This is the right place to do some initialization or sending initial
hello messages.
"""
pass
@abc.abstractmethod
def connection_lost(self, reason):
"""Handler called when connection to peer/remote according to protocol
has been lost.
Here we can do any clean-up related to connection/transport/timers/etc.
"""
pass
class Factory(object, metaclass=abc.ABCMeta):
"""This is a factory which produces protocols.
Can also act as context for protocols.
"""
# Put a subclass of Protocol here:
protocol = None
@abc.abstractmethod
def build_protocol(self, socket):
"""Create an instance of a subclass of Protocol.
Override this method to alter how Protocol instances get created.
"""
raise NotImplementedError()
@abc.abstractmethod
def start_protocol(self, socket):
"""Launch protocol instance to handle input on an incoming connection.
"""
raise NotImplementedError()
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