root / ncclient / transport / session.py @ 0cdb8b3c
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1 | d095a59e | Shikhar Bhushan | # Copyright 2009 Shikhar Bhushan
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2 | d095a59e | Shikhar Bhushan | #
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3 | d095a59e | Shikhar Bhushan | # Licensed under the Apache License, Version 2.0 (the "License");
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4 | d095a59e | Shikhar Bhushan | # you may not use this file except in compliance with the License.
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5 | d095a59e | Shikhar Bhushan | # You may obtain a copy of the License at
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6 | d095a59e | Shikhar Bhushan | #
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7 | d095a59e | Shikhar Bhushan | # http://www.apache.org/licenses/LICENSE-2.0
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8 | d095a59e | Shikhar Bhushan | #
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9 | d095a59e | Shikhar Bhushan | # Unless required by applicable law or agreed to in writing, software
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10 | d095a59e | Shikhar Bhushan | # distributed under the License is distributed on an "AS IS" BASIS,
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11 | d095a59e | Shikhar Bhushan | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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12 | d095a59e | Shikhar Bhushan | # See the License for the specific language governing permissions and
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13 | d095a59e | Shikhar Bhushan | # limitations under the License.
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14 | d095a59e | Shikhar Bhushan | |
15 | d6688264 | Shikhar Bhushan | from Queue import Queue |
16 | 4de03d63 | Shikhar Bhushan | from threading import Thread, Lock, Event |
17 | e91a5349 | Shikhar Bhushan | |
18 | 583c11f6 | Shikhar Bhushan | from ncclient import content |
19 | 2f8bc438 | Shikhar Bhushan | from ncclient.capabilities import Capabilities |
20 | d095a59e | Shikhar Bhushan | |
21 | 41e2ed46 | Shikhar Bhushan | import logging |
22 | 41e2ed46 | Shikhar Bhushan | logger = logging.getLogger('ncclient.transport.session')
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23 | 41e2ed46 | Shikhar Bhushan | |
24 | a14c36f9 | Shikhar Bhushan | class Session(Thread): |
25 | 0cdb8b3c | Shikhar Bhushan | "This is a base class for use by protocol implementations"
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26 | d095a59e | Shikhar Bhushan | |
27 | 2f8bc438 | Shikhar Bhushan | def __init__(self, capabilities): |
28 | a14c36f9 | Shikhar Bhushan | Thread.__init__(self)
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29 | 583c11f6 | Shikhar Bhushan | self.set_daemon(True) |
30 | 583c11f6 | Shikhar Bhushan | self._listeners = set() # 3.0's weakset ideal |
31 | a14c36f9 | Shikhar Bhushan | self._lock = Lock()
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32 | 583c11f6 | Shikhar Bhushan | self.set_name('session') |
33 | d6688264 | Shikhar Bhushan | self._q = Queue()
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34 | 2f8bc438 | Shikhar Bhushan | self._client_capabilities = capabilities
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35 | d095a59e | Shikhar Bhushan | self._server_capabilities = None # yet |
36 | d095a59e | Shikhar Bhushan | self._id = None # session-id |
37 | d095a59e | Shikhar Bhushan | self._connected = False # to be set/cleared by subclass implementation |
38 | 41e2ed46 | Shikhar Bhushan | logger.debug('%r created: client_capabilities=%r' %
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39 | 41e2ed46 | Shikhar Bhushan | (self, self._client_capabilities)) |
40 | d095a59e | Shikhar Bhushan | |
41 | a14c36f9 | Shikhar Bhushan | def _dispatch_message(self, raw): |
42 | a14c36f9 | Shikhar Bhushan | try:
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43 | 583c11f6 | Shikhar Bhushan | root = content.parse_root(raw) |
44 | a14c36f9 | Shikhar Bhushan | except Exception as e: |
45 | a14c36f9 | Shikhar Bhushan | logger.error('error parsing dispatch message: %s' % e)
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46 | a14c36f9 | Shikhar Bhushan | return
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47 | a14c36f9 | Shikhar Bhushan | with self._lock: |
48 | a14c36f9 | Shikhar Bhushan | listeners = list(self._listeners) |
49 | a14c36f9 | Shikhar Bhushan | for l in listeners: |
50 | a14c36f9 | Shikhar Bhushan | logger.debug('dispatching message to %r' % l)
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51 | a14c36f9 | Shikhar Bhushan | try:
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52 | a14c36f9 | Shikhar Bhushan | l.callback(root, raw) |
53 | a14c36f9 | Shikhar Bhushan | except Exception as e: |
54 | a14c36f9 | Shikhar Bhushan | logger.warning('[error] %r' % e)
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55 | a14c36f9 | Shikhar Bhushan | |
56 | a14c36f9 | Shikhar Bhushan | def _dispatch_error(self, err): |
57 | a14c36f9 | Shikhar Bhushan | with self._lock: |
58 | a14c36f9 | Shikhar Bhushan | listeners = list(self._listeners) |
59 | a14c36f9 | Shikhar Bhushan | for l in listeners: |
60 | a14c36f9 | Shikhar Bhushan | logger.debug('dispatching error to %r' % l)
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61 | a14c36f9 | Shikhar Bhushan | try:
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62 | a14c36f9 | Shikhar Bhushan | l.errback(err) |
63 | a14c36f9 | Shikhar Bhushan | except Exception as e: |
64 | a14c36f9 | Shikhar Bhushan | logger.warning('error %r' % e)
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65 | a14c36f9 | Shikhar Bhushan | |
66 | 65c6a607 | Shikhar Bhushan | def _post_connect(self): |
67 | 65c6a607 | Shikhar Bhushan | "Greeting stuff"
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68 | 65c6a607 | Shikhar Bhushan | init_event = Event() |
69 | 65c6a607 | Shikhar Bhushan | error = [None] # so that err_cb can bind error[0]. just how it is. |
70 | 65c6a607 | Shikhar Bhushan | # callbacks
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71 | 65c6a607 | Shikhar Bhushan | def ok_cb(id, capabilities): |
72 | 65c6a607 | Shikhar Bhushan | self._id = id |
73 | 583c11f6 | Shikhar Bhushan | self._server_capabilities = capabilities
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74 | 65c6a607 | Shikhar Bhushan | init_event.set() |
75 | 65c6a607 | Shikhar Bhushan | def err_cb(err): |
76 | 65c6a607 | Shikhar Bhushan | error[0] = err
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77 | 65c6a607 | Shikhar Bhushan | init_event.set() |
78 | 65c6a607 | Shikhar Bhushan | listener = HelloHandler(ok_cb, err_cb) |
79 | 65c6a607 | Shikhar Bhushan | self.add_listener(listener)
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80 | 65c6a607 | Shikhar Bhushan | self.send(HelloHandler.build(self._client_capabilities)) |
81 | 65c6a607 | Shikhar Bhushan | logger.debug('starting main loop')
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82 | 65c6a607 | Shikhar Bhushan | self.start()
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83 | 65c6a607 | Shikhar Bhushan | # we expect server's hello message
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84 | 65c6a607 | Shikhar Bhushan | init_event.wait() |
85 | 65c6a607 | Shikhar Bhushan | # received hello message or an error happened
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86 | 65c6a607 | Shikhar Bhushan | self.remove_listener(listener)
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87 | 65c6a607 | Shikhar Bhushan | if error[0]: |
88 | 65c6a607 | Shikhar Bhushan | raise error[0] |
89 | 0cdb8b3c | Shikhar Bhushan | logger.info('initialized: session-id=%s | server_capabilities=%s' % (self._id, self._server_capabilities)) |
90 | 65c6a607 | Shikhar Bhushan | |
91 | a14c36f9 | Shikhar Bhushan | def add_listener(self, listener): |
92 | 0cdb8b3c | Shikhar Bhushan | """Register a listener that will be notified of incoming messages and errors.
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93 | 0cdb8b3c | Shikhar Bhushan |
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94 | 0cdb8b3c | Shikhar Bhushan | :type listener: :class:`SessionListener`
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95 | 0cdb8b3c | Shikhar Bhushan | """
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96 | a14c36f9 | Shikhar Bhushan | logger.debug('installing listener %r' % listener)
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97 | 583c11f6 | Shikhar Bhushan | if not isinstance(listener, SessionListener): |
98 | 583c11f6 | Shikhar Bhushan | raise SessionError("Listener must be a SessionListener type") |
99 | a14c36f9 | Shikhar Bhushan | with self._lock: |
100 | a14c36f9 | Shikhar Bhushan | self._listeners.add(listener)
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101 | a14c36f9 | Shikhar Bhushan | |
102 | a14c36f9 | Shikhar Bhushan | def remove_listener(self, listener): |
103 | 0cdb8b3c | Shikhar Bhushan | "Unregister some listener; ignoring if the listener was never registered."
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104 | a14c36f9 | Shikhar Bhushan | logger.debug('discarding listener %r' % listener)
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105 | a14c36f9 | Shikhar Bhushan | with self._lock: |
106 | a14c36f9 | Shikhar Bhushan | self._listeners.discard(listener)
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107 | a14c36f9 | Shikhar Bhushan | |
108 | a14c36f9 | Shikhar Bhushan | def get_listener_instance(self, cls): |
109 | 0cdb8b3c | Shikhar Bhushan | """If a listener of the specified type is registered, returns it. This is useful when it is desirable to have only one instance of a particular type per session, i.e. a multiton.
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110 | 0cdb8b3c | Shikhar Bhushan |
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111 | 0cdb8b3c | Shikhar Bhushan | :type cls: :class:`type`
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112 | 0cdb8b3c | Shikhar Bhushan | :rtype: :class:`SessionListener` or :const:`None`
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113 | 0cdb8b3c | Shikhar Bhushan | """
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114 | a14c36f9 | Shikhar Bhushan | with self._lock: |
115 | a14c36f9 | Shikhar Bhushan | for listener in self._listeners: |
116 | a14c36f9 | Shikhar Bhushan | if isinstance(listener, cls): |
117 | a14c36f9 | Shikhar Bhushan | return listener
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118 | a14c36f9 | Shikhar Bhushan | |
119 | 0cdb8b3c | Shikhar Bhushan | def connect(self, *args, **kwds): # subclass implements |
120 | d095a59e | Shikhar Bhushan | raise NotImplementedError |
121 | d095a59e | Shikhar Bhushan | |
122 | 0cdb8b3c | Shikhar Bhushan | def run(self): # subclass implements |
123 | d095a59e | Shikhar Bhushan | raise NotImplementedError |
124 | d095a59e | Shikhar Bhushan | |
125 | d6688264 | Shikhar Bhushan | def send(self, message): |
126 | 0cdb8b3c | Shikhar Bhushan | """
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127 | 0cdb8b3c | Shikhar Bhushan | :param message: XML document
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128 | 0cdb8b3c | Shikhar Bhushan | :type message: string
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129 | 0cdb8b3c | Shikhar Bhushan | """
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130 | d6688264 | Shikhar Bhushan | logger.debug('queueing %s' % message)
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131 | d6688264 | Shikhar Bhushan | self._q.put(message)
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132 | d6688264 | Shikhar Bhushan | |
133 | d095a59e | Shikhar Bhushan | ### Properties
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134 | 0cdb8b3c | Shikhar Bhushan | |
135 | 0cdb8b3c | Shikhar Bhushan | @property
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136 | 0cdb8b3c | Shikhar Bhushan | def connected(self): |
137 | 0cdb8b3c | Shikhar Bhushan | ":rtype: bool"
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138 | 0cdb8b3c | Shikhar Bhushan | return self._connected |
139 | 0cdb8b3c | Shikhar Bhushan | |
140 | d095a59e | Shikhar Bhushan | @property
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141 | d095a59e | Shikhar Bhushan | def client_capabilities(self): |
142 | 0cdb8b3c | Shikhar Bhushan | ":rtype: :class:`Capabilities`"
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143 | d095a59e | Shikhar Bhushan | return self._client_capabilities |
144 | d095a59e | Shikhar Bhushan | |
145 | d095a59e | Shikhar Bhushan | @property
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146 | d095a59e | Shikhar Bhushan | def server_capabilities(self): |
147 | 0cdb8b3c | Shikhar Bhushan | ":rtype: :class:`Capabilities` or :const:`None`"
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148 | d095a59e | Shikhar Bhushan | return self._server_capabilities |
149 | d095a59e | Shikhar Bhushan | |
150 | d095a59e | Shikhar Bhushan | @property
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151 | d095a59e | Shikhar Bhushan | def id(self): |
152 | 0cdb8b3c | Shikhar Bhushan | ":rtype: :obj:`string` or :const:`None`"
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153 | d095a59e | Shikhar Bhushan | return self._id |
154 | 94803aaf | Shikhar Bhushan | |
155 | 94803aaf | Shikhar Bhushan | @property
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156 | 94803aaf | Shikhar Bhushan | def can_pipeline(self): |
157 | 0cdb8b3c | Shikhar Bhushan | ":rtype: :obj:`bool`"
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158 | 94803aaf | Shikhar Bhushan | return True |
159 | 583c11f6 | Shikhar Bhushan | |
160 | 583c11f6 | Shikhar Bhushan | |
161 | 583c11f6 | Shikhar Bhushan | class SessionListener(object): |
162 | 583c11f6 | Shikhar Bhushan | |
163 | 0cdb8b3c | Shikhar Bhushan | """'Listen' to incoming messages on a NETCONF :class:`Session`
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164 | 0cdb8b3c | Shikhar Bhushan |
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165 | 0cdb8b3c | Shikhar Bhushan | .. note::
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166 | 0cdb8b3c | Shikhar Bhushan | Avoid computationally intensive tasks in the callbacks.
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167 | 0cdb8b3c | Shikhar Bhushan | """
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168 | 0cdb8b3c | Shikhar Bhushan | |
169 | 583c11f6 | Shikhar Bhushan | def callback(self, root, raw): |
170 | 0cdb8b3c | Shikhar Bhushan | """Called when a new XML document is received. The `root` argument allows the callback to determine whether it wants to further process the document.
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171 | 0cdb8b3c | Shikhar Bhushan |
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172 | 0cdb8b3c | Shikhar Bhushan | :param root: tuple of (tag, attrs) where tag is the qualified name of the root element and attrs is a dictionary of its attributes (also qualified names)
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173 | 0cdb8b3c | Shikhar Bhushan | :param raw: XML document
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174 | 0cdb8b3c | Shikhar Bhushan | :type raw: string
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175 | 0cdb8b3c | Shikhar Bhushan | """
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176 | 583c11f6 | Shikhar Bhushan | raise NotImplementedError |
177 | 583c11f6 | Shikhar Bhushan | |
178 | 583c11f6 | Shikhar Bhushan | def errback(self, ex): |
179 | 0cdb8b3c | Shikhar Bhushan | """Called when an error occurs.
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180 | 0cdb8b3c | Shikhar Bhushan |
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181 | 0cdb8b3c | Shikhar Bhushan | :type ex: :class:`Exception`
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182 | 0cdb8b3c | Shikhar Bhushan | """
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183 | 583c11f6 | Shikhar Bhushan | raise NotImplementedError |
184 | 583c11f6 | Shikhar Bhushan | |
185 | 583c11f6 | Shikhar Bhushan | |
186 | 583c11f6 | Shikhar Bhushan | class HelloHandler(SessionListener): |
187 | 583c11f6 | Shikhar Bhushan | |
188 | 583c11f6 | Shikhar Bhushan | def __init__(self, init_cb, error_cb): |
189 | 583c11f6 | Shikhar Bhushan | self._init_cb = init_cb
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190 | 583c11f6 | Shikhar Bhushan | self._error_cb = error_cb
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191 | 583c11f6 | Shikhar Bhushan | |
192 | 583c11f6 | Shikhar Bhushan | def callback(self, root, raw): |
193 | 583c11f6 | Shikhar Bhushan | if content.unqualify(root[0]) == 'hello': |
194 | 583c11f6 | Shikhar Bhushan | try:
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195 | 583c11f6 | Shikhar Bhushan | id, capabilities = HelloHandler.parse(raw)
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196 | 583c11f6 | Shikhar Bhushan | except Exception as e: |
197 | 583c11f6 | Shikhar Bhushan | self._error_cb(e)
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198 | 583c11f6 | Shikhar Bhushan | else:
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199 | 583c11f6 | Shikhar Bhushan | self._init_cb(id, capabilities) |
200 | 583c11f6 | Shikhar Bhushan | |
201 | 583c11f6 | Shikhar Bhushan | def errback(self, err): |
202 | 583c11f6 | Shikhar Bhushan | self._error_cb(err)
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203 | 583c11f6 | Shikhar Bhushan | |
204 | 583c11f6 | Shikhar Bhushan | @staticmethod
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205 | 583c11f6 | Shikhar Bhushan | def build(capabilities): |
206 | 583c11f6 | Shikhar Bhushan | "Given a list of capability URI's returns <hello> message XML string"
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207 | 583c11f6 | Shikhar Bhushan | spec = { |
208 | 583c11f6 | Shikhar Bhushan | 'tag': content.qualify('hello'), |
209 | 583c11f6 | Shikhar Bhushan | 'subtree': [{
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210 | 583c11f6 | Shikhar Bhushan | 'tag': 'capabilities', |
211 | 583c11f6 | Shikhar Bhushan | 'subtree': # this is fun :-) |
212 | 583c11f6 | Shikhar Bhushan | [{'tag': 'capability', 'text': uri} for uri in capabilities] |
213 | 583c11f6 | Shikhar Bhushan | }] |
214 | 583c11f6 | Shikhar Bhushan | } |
215 | 583c11f6 | Shikhar Bhushan | return content.dtree2xml(spec)
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216 | 583c11f6 | Shikhar Bhushan | |
217 | 583c11f6 | Shikhar Bhushan | @staticmethod
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218 | 583c11f6 | Shikhar Bhushan | def parse(raw): |
219 | 583c11f6 | Shikhar Bhushan | "Returns tuple of (session-id (str), capabilities (Capabilities)"
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220 | 583c11f6 | Shikhar Bhushan | sid, capabilities = 0, []
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221 | 583c11f6 | Shikhar Bhushan | root = content.xml2ele(raw) |
222 | 583c11f6 | Shikhar Bhushan | for child in root.getchildren(): |
223 | 583c11f6 | Shikhar Bhushan | tag = content.unqualify(child.tag) |
224 | 583c11f6 | Shikhar Bhushan | if tag == 'session-id': |
225 | 583c11f6 | Shikhar Bhushan | sid = child.text |
226 | 583c11f6 | Shikhar Bhushan | elif tag == 'capabilities': |
227 | 583c11f6 | Shikhar Bhushan | for cap in child.getchildren(): |
228 | 583c11f6 | Shikhar Bhushan | if content.unqualify(cap.tag) == 'capability': |
229 | 583c11f6 | Shikhar Bhushan | capabilities.append(cap.text) |
230 | 583c11f6 | Shikhar Bhushan | return sid, Capabilities(capabilities) |