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# Copyright 2009 Shikhar Bhushan
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#    http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from content import Creator, Parser
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from threading import Thread
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from listener import Subject, Listener
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class SessionError(ncclientError): pass
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class Session(Thread, Subject, Listener):
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    def __init__(self, capabilities=None):
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        Thread.__init__(self, name='session')
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        Subject.__init__(self, listeners=[self])
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        Thread.setDaemon(True)
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        self.client_capabilities = capabilities
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        self.server_capabilities = None # yet
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        self.id = None # session-id
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        self.is_connected = False
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        self._q = Queue.Queue()
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    def _make_hello(self):
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        pass
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    def _init(self, id, capabilities):
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        self.id = id
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        self.capabilities[SERVER] = capabilities
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        self.is_connected = True
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    @override
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    def _close(self):
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        raise NotImplementedError
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    def connect(self):
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        self._greet()
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        Thread.start()
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    def send(self, msg):
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        if self.is_connected:
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            self._q.add(msg)
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        else:
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            raise SessionError('Attempted to send message while not connected')
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    ### Thread methods
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    @override
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    def run(self):
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        raise NotImplementedError
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    ### Subject methods
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    def add_listener(self, listener):
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        if not self.is_connected:
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            raise SessionError('Listeners may only be added after session initialisation')
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        else:
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            Subject.add_listner(self, listener)
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    ### Listener methods
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    # these are relevant for the initial greeting only
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    def reply(self, data):
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        p = Parser(data)
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        s = p['session']
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        id = s['@id']
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        capabilities = Capabilities()
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        capabilities.fromXML(p['capabilities'])
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        self._init(id, capabilities)
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        self.remove_listener(self)
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    def error(self, data):
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        self._close()
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        raise SSHError('Session initialization failed')
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