code.grnet.gr Git - ncclient/blob - ncclient/session.py

   1 # Copyright 2009 Shikhar Bhushan
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #    http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14
  15 import logging
  16
  17 import content
  18
  19 from threading import Thread, Event
  20 from Queue import Queue
  21
  22 from capability import CAPABILITIES
  23 from error import ClientError
  24 from subject import Subject
  25
  26 logger = logging.getLogger('ncclient.session')
  27
  28 class SessionError(ClientError):
  29
  30     pass
  31
  32 class Session(Thread, Subject):
  33
  34     def __init__(self):
  35         Thread.__init__(self, name='session')
  36         Subject.__init__(self, listeners=[Session.HelloListener(self)])
  37         self._client_capabilities = CAPABILITIES
  38         self._server_capabilities = None # yet
  39         self._id = None # session-id
  40         self._connected = False
  41         self._error = None
  42         self._init_event = Event()
  43         self._q = Queue()
  44
  45     def connect(self):
  46         raise NotImplementedError
  47
  48     def send(self, message):
  49         message = (u'<?xml version="1.0" encoding="UTF-8"?>%s' % message).encode('utf-8')
  50         logger.debug('queueing message: \n%s' % message)
  51         self._q.put(message)
  52
  53     def run(self):
  54         raise NotImplementedError
  55
  56     ### Properties
  57
  58     @property
  59     def client_capabilities(self):
  60         return self._client_capabilities
  61
  62     @property
  63     def serve_capabilities(self):
  64         return self._server_capabilities
  65
  66     @property
  67     def connected(self):
  68         return self._connected
  69
  70     @property
  71     def id(self):
  72         return self._id
  73
  74     class HelloListener:
  75
  76         def __init__(self, session):
  77             self._session = session
  78
  79         def _done(self, err=None):
  80             if err is not None:
  81                 self._session._error = err
  82             self._session.remove_listener(self)
  83             self._session._init_event.set()
  84
  85         def reply(self, data):
  86             err = None
  87             try:
  88                 id, capabilities = content.parse_hello(data)
  89                 logger.debug('session_id: %s | capabilities: \n%s', id, capabilities)
  90                 self._session._id, self._session.capabilities = id, capabilities
  91             except Exception as e:
  92                 err = e
  93             finally:
  94                 self._done(err)
  95
  96         def close(self, err):
  97             self._done(err)
  98
  99     ### Methods for which subclasses should call super after they are done
 100
 101     def _connect(self):
 102         self._connected = True
 103         # start the subclass' main loop
 104         self.start()
 105         # queue client's hello message for sending
 106         self.send(content.make_hello(self._client_capabilities))
 107         # we expect server's hello message, wait for _init_event to be set by HelloListener
 108         self._init_event.wait()
 109         # there may have been an error
 110         if self._error:
 111             self._close()
 112             raise self._error
 113
 114     def _close(self):
 115         self._connected = False