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 from threading import Thread, Event
  17 from Queue import Queue
  18
  19 from capability import CAPABILITIES
  20 from content import hello
  21 from error import ClientError
  22 from subject import Subject
  23
  24 logger = logging.getLogger('ncclient.session')
  25
  26 class SessionError(ClientError):
  27
  28     pass
  29
  30 class Session(Thread, Subject):
  31
  32     def __init__(self):
  33         Thread.__init__(self, name='session')
  34         Subject.__init__(self, listeners=[Session.HelloListener(self)])
  35         self._client_capabilities = CAPABILITIES
  36         self._server_capabilities = None # yet
  37         self._id = None # session-id
  38         self._connected = False
  39         self._error = None
  40         self._init_event = Event()
  41         self._q = Queue()
  42
  43     def connect(self):
  44         raise NotImplementedError
  45
  46     def send(self, message):
  47         message = (u'<?xml version="1.0" encoding="UTF-8"?>%s' % message).encode('utf-8')
  48         logger.debug('queueing message: \n%s' % message)
  49         self._q.put(message)
  50
  51     def run(self):
  52         raise NotImplementedError
  53
  54     ### Properties
  55
  56     @property
  57     def client_capabilities(self):
  58         return self._client_capabilities
  59
  60     @property
  61     def serve_capabilities(self):
  62         return self._server_capabilities
  63
  64     @property
  65     def connected(self):
  66         return self._connected
  67
  68     @property
  69     def id(self):
  70         return self._id
  71
  72     class HelloListener:
  73
  74         def __init__(self, session):
  75             self._session = session
  76
  77         def _done(self, err=None):
  78             if err is not None:
  79                 self._session._error = err
  80             self._session.remove_listener(self)
  81             self._session._init_event.set()
  82
  83         ### Events
  84
  85         def reply(self, data):
  86             err = None
  87             try:
  88                 id, capabilities = hello.parse(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(hello.make(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