1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
# -*- test-case-name: twisted.words.test.test_xmlstream -*-
#
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
XML Stream processing.
An XML Stream is defined as a connection over which two XML documents are
exchanged during the lifetime of the connection, one for each direction. The
unit of interaction is a direct child element of the root element (stanza).
The most prominent use of XML Streams is Jabber, but this module is generically
usable. See Twisted Words for Jabber specific protocol support.
Maintainer: Ralph Meijer
"""
from twisted.python import failure
from twisted.internet import protocol
from twisted.words.xish import domish, utility
STREAM_CONNECTED_EVENT = intern("//event/stream/connected")
STREAM_START_EVENT = intern("//event/stream/start")
STREAM_END_EVENT = intern("//event/stream/end")
STREAM_ERROR_EVENT = intern("//event/stream/error")
class XmlStream(protocol.Protocol, utility.EventDispatcher):
""" Generic Streaming XML protocol handler.
This protocol handler will parse incoming data as XML and dispatch events
accordingly. Incoming stanzas can be handled by registering observers using
XPath-like expressions that are matched against each stanza. See
L{utility.EventDispatcher} for details.
"""
def __init__(self):
utility.EventDispatcher.__init__(self)
self.stream = None
self.rawDataOutFn = None
self.rawDataInFn = None
def _initializeStream(self):
""" Sets up XML Parser. """
self.stream = domish.elementStream()
self.stream.DocumentStartEvent = self.onDocumentStart
self.stream.ElementEvent = self.onElement
self.stream.DocumentEndEvent = self.onDocumentEnd
### --------------------------------------------------------------
###
### Protocol events
###
### --------------------------------------------------------------
def connectionMade(self):
""" Called when a connection is made.
Sets up the XML parser and dispatches the L{STREAM_CONNECTED_EVENT}
event indicating the connection has been established.
"""
self._initializeStream()
self.dispatch(self, STREAM_CONNECTED_EVENT)
def dataReceived(self, data):
""" Called whenever data is received.
Passes the data to the XML parser. This can result in calls to the
DOM handlers. If a parse error occurs, the L{STREAM_ERROR_EVENT} event
is called to allow for cleanup actions, followed by dropping the
connection.
"""
try:
if self.rawDataInFn:
self.rawDataInFn(data)
self.stream.parse(data)
except domish.ParserError:
self.dispatch(failure.Failure(), STREAM_ERROR_EVENT)
self.transport.loseConnection()
def connectionLost(self, reason):
""" Called when the connection is shut down.
Dispatches the L{STREAM_END_EVENT}.
"""
self.dispatch(reason, STREAM_END_EVENT)
self.stream = None
### --------------------------------------------------------------
###
### DOM events
###
### --------------------------------------------------------------
def onDocumentStart(self, rootElement):
""" Called whenever the start tag of a root element has been received.
Dispatches the L{STREAM_START_EVENT}.
"""
self.dispatch(self, STREAM_START_EVENT)
def onElement(self, element):
""" Called whenever a direct child element of the root element has
been received.
Dispatches the received element.
"""
self.dispatch(element)
def onDocumentEnd(self):
""" Called whenever the end tag of the root element has been received.
Closes the connection. This causes C{connectionLost} being called.
"""
self.transport.loseConnection()
def setDispatchFn(self, fn):
""" Set another function to handle elements. """
self.stream.ElementEvent = fn
def resetDispatchFn(self):
""" Set the default function (C{onElement}) to handle elements. """
self.stream.ElementEvent = self.onElement
def send(self, obj):
""" Send data over the stream.
Sends the given C{obj} over the connection. C{obj} may be instances of
L{domish.Element}, C{unicode} and C{str}. The first two will be
properly serialized and/or encoded. C{str} objects must be in UTF-8
encoding.
Note: because it is easy to make mistakes in maintaining a properly
encoded C{str} object, it is advised to use C{unicode} objects
everywhere when dealing with XML Streams.
@param obj: Object to be sent over the stream.
@type obj: L{domish.Element}, L{domish} or C{str}
"""
if domish.IElement.providedBy(obj):
obj = obj.toXml()
if isinstance(obj, unicode):
obj = obj.encode('utf-8')
if self.rawDataOutFn:
self.rawDataOutFn(obj)
self.transport.write(obj)
class BootstrapMixin(object):
"""
XmlStream factory mixin to install bootstrap event observers.
This mixin is for factories providing
L{IProtocolFactory<twisted.internet.interfaces.IProtocolFactory>} to make
sure bootstrap event observers are set up on protocols, before incoming
data is processed. Such protocols typically derive from
L{utility.EventDispatcher}, like L{XmlStream}.
You can set up bootstrap event observers using C{addBootstrap}. The
C{event} and C{fn} parameters correspond with the C{event} and
C{observerfn} arguments to L{utility.EventDispatcher.addObserver}.
@since: 8.2.
@ivar bootstraps: The list of registered bootstrap event observers.
@type bootstrap: C{list}
"""
def __init__(self):
self.bootstraps = []
def installBootstraps(self, dispatcher):
"""
Install registered bootstrap observers.
@param dispatcher: Event dispatcher to add the observers to.
@type dispatcher: L{utility.EventDispatcher}
"""
for event, fn in self.bootstraps:
dispatcher.addObserver(event, fn)
def addBootstrap(self, event, fn):
"""
Add a bootstrap event handler.
@param event: The event to register an observer for.
@type event: C{str} or L{xpath.XPathQuery}
@param fn: The observer callable to be registered.
"""
self.bootstraps.append((event, fn))
def removeBootstrap(self, event, fn):
"""
Remove a bootstrap event handler.
@param event: The event the observer is registered for.
@type event: C{str} or L{xpath.XPathQuery}
@param fn: The registered observer callable.
"""
self.bootstraps.remove((event, fn))
class XmlStreamFactoryMixin(BootstrapMixin):
"""
XmlStream factory mixin that takes care of event handlers.
All positional and keyword arguments passed to create this factory are
passed on as-is to the protocol.
@ivar args: Positional arguments passed to the protocol upon instantiation.
@type args: C{tuple}.
@ivar kwargs: Keyword arguments passed to the protocol upon instantiation.
@type kwargs: C{dict}.
"""
def __init__(self, *args, **kwargs):
BootstrapMixin.__init__(self)
self.args = args
self.kwargs = kwargs
def buildProtocol(self, addr):
"""
Create an instance of XmlStream.
The returned instance will have bootstrap event observers registered
and will proceed to handle input on an incoming connection.
"""
xs = self.protocol(*self.args, **self.kwargs)
xs.factory = self
self.installBootstraps(xs)
return xs
class XmlStreamFactory(XmlStreamFactoryMixin,
protocol.ReconnectingClientFactory):
"""
Factory for XmlStream protocol objects as a reconnection client.
"""
protocol = XmlStream
def buildProtocol(self, addr):
"""
Create a protocol instance.
Overrides L{XmlStreamFactoryMixin.buildProtocol} to work with
a L{ReconnectingClientFactory}. As this is called upon having an
connection established, we are resetting the delay for reconnection
attempts when the connection is lost again.
"""
self.resetDelay()
return XmlStreamFactoryMixin.buildProtocol(self, addr)
|
