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
|
# -*- test-case-name: twisted.test.test_pb -*-
# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Utility classes for spread.
"""
from zope.interface import implementer
from twisted.internet import defer, interfaces
from twisted.protocols import basic
from twisted.python.failure import Failure
from twisted.spread import pb
class LocalMethod:
def __init__(self, local, name):
self.local = local
self.name = name
def __call__(self, *args, **kw):
return self.local.callRemote(self.name, *args, **kw)
class LocalAsRemote:
"""
A class useful for emulating the effects of remote behavior locally.
"""
reportAllTracebacks = 1
def callRemote(self, name, *args, **kw):
"""
Call a specially-designated local method.
self.callRemote('x') will first try to invoke a method named
sync_x and return its result (which should probably be a
Deferred). Second, it will look for a method called async_x,
which will be called and then have its result (or Failure)
automatically wrapped in a Deferred.
"""
if hasattr(self, "sync_" + name):
return getattr(self, "sync_" + name)(*args, **kw)
try:
method = getattr(self, "async_" + name)
return defer.succeed(method(*args, **kw))
except BaseException:
f = Failure()
if self.reportAllTracebacks:
f.printTraceback()
return defer.fail(f)
def remoteMethod(self, name):
return LocalMethod(self, name)
class LocalAsyncForwarder:
"""
A class useful for forwarding a locally-defined interface.
"""
def __init__(self, forwarded, interfaceClass, failWhenNotImplemented=0):
assert interfaceClass.providedBy(forwarded)
self.forwarded = forwarded
self.interfaceClass = interfaceClass
self.failWhenNotImplemented = failWhenNotImplemented
def _callMethod(self, method, *args, **kw):
return getattr(self.forwarded, method)(*args, **kw)
def callRemote(self, method, *args, **kw):
if self.interfaceClass.queryDescriptionFor(method):
result = defer.maybeDeferred(self._callMethod, method, *args, **kw)
return result
elif self.failWhenNotImplemented:
return defer.fail(
Failure(NotImplementedError, "No Such Method in Interface: %s" % method)
)
else:
return defer.succeed(None)
class Pager:
"""
I am an object which pages out information.
"""
def __init__(self, collector, callback=None, *args, **kw):
"""
Create a pager with a Reference to a remote collector and
an optional callable to invoke upon completion.
"""
if callable(callback):
self.callback = callback
self.callbackArgs = args
self.callbackKeyword = kw
else:
self.callback = None
self._stillPaging = 1
self.collector = collector
collector.broker.registerPageProducer(self)
def stillPaging(self):
"""
(internal) Method called by Broker.
"""
if not self._stillPaging:
self.collector.callRemote("endedPaging", pbanswer=False)
if self.callback is not None:
self.callback(*self.callbackArgs, **self.callbackKeyword)
return self._stillPaging
def sendNextPage(self):
"""
(internal) Method called by Broker.
"""
self.collector.callRemote("gotPage", self.nextPage(), pbanswer=False)
def nextPage(self):
"""
Override this to return an object to be sent to my collector.
"""
raise NotImplementedError()
def stopPaging(self):
"""
Call this when you're done paging.
"""
self._stillPaging = 0
class StringPager(Pager):
"""
A simple pager that splits a string into chunks.
"""
def __init__(self, collector, st, chunkSize=8192, callback=None, *args, **kw):
self.string = st
self.pointer = 0
self.chunkSize = chunkSize
Pager.__init__(self, collector, callback, *args, **kw)
def nextPage(self):
val = self.string[self.pointer : self.pointer + self.chunkSize]
self.pointer += self.chunkSize
if self.pointer >= len(self.string):
self.stopPaging()
return val
@implementer(interfaces.IConsumer)
class FilePager(Pager):
"""
Reads a file in chunks and sends the chunks as they come.
"""
def __init__(self, collector, fd, callback=None, *args, **kw):
self.chunks = []
Pager.__init__(self, collector, callback, *args, **kw)
self.startProducing(fd)
def startProducing(self, fd):
self.deferred = basic.FileSender().beginFileTransfer(fd, self)
self.deferred.addBoth(lambda x: self.stopPaging())
def registerProducer(self, producer, streaming):
self.producer = producer
if not streaming:
self.producer.resumeProducing()
def unregisterProducer(self):
self.producer = None
def write(self, chunk):
self.chunks.append(chunk)
def sendNextPage(self):
"""
Get the first chunk read and send it to collector.
"""
if not self.chunks:
return
val = self.chunks.pop(0)
self.producer.resumeProducing()
self.collector.callRemote("gotPage", val, pbanswer=False)
# Utility paging stuff.
class CallbackPageCollector(pb.Referenceable):
"""
I receive pages from the peer. You may instantiate a Pager with a
remote reference to me. I will call the callback with a list of pages
once they are all received.
"""
def __init__(self, callback):
self.pages = []
self.callback = callback
def remote_gotPage(self, page):
self.pages.append(page)
def remote_endedPaging(self):
self.callback(self.pages)
def getAllPages(referenceable, methodName, *args, **kw):
"""
A utility method that will call a remote method which expects a
PageCollector as the first argument.
"""
d = defer.Deferred()
referenceable.callRemote(methodName, CallbackPageCollector(d.callback), *args, **kw)
return d
|
