96 lines
3.4 KiB
Python
96 lines
3.4 KiB
Python
###############################################################################
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#
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# The MIT License (MIT)
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#
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# Copyright (c) Tavendo GmbH
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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#
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###############################################################################
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import hashlib
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from twisted.internet import reactor
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from autobahn.twisted.websocket import WebSocketServerFactory, \
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WebSocketServerProtocol, \
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listenWS
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from streaming_client import BATCH_SIZE
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class StreamingHashServerProtocol(WebSocketServerProtocol):
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"""
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Streaming WebSockets server that computes a running SHA-256 for data
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received. It will respond every BATCH_SIZE bytes with the digest
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up to that point. It can receive messages of unlimited number of frames
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and frames of unlimited length (actually, up to 2^63, which is the
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WebSockets protocol imposed limit on frame size). Digest is reset upon
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new message.
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"""
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def onMessageBegin(self, isBinary):
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WebSocketServerProtocol.onMessageBegin(self, isBinary)
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self.sha256 = hashlib.sha256()
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self.count = 0
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self.received = 0
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self.next = BATCH_SIZE
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def onMessageFrameBegin(self, length):
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WebSocketServerProtocol.onMessageFrameBegin(self, length)
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def onMessageFrameData(self, payload):
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length = len(payload)
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self.received += length
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# when the data received exceeds the next BATCH_SIZE ..
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if self.received >= self.next:
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# update digest up to batch size
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rest = length - (self.received - self.next)
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self.sha256.update(payload[:rest])
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# send digest
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digest = self.sha256.hexdigest()
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self.sendMessage(digest.encode('utf8'))
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print("Sent digest for batch {} : {}".format(self.count, digest))
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# advance to next batch
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self.next += BATCH_SIZE
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self.count += 1
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# .. and update the digest for the rest
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self.sha256.update(payload[rest:])
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else:
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# otherwise we just update the digest for received data
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self.sha256.update(payload)
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def onMessageFrameEnd(self):
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pass
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def onMessageEnd(self):
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pass
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if __name__ == '__main__':
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factory = WebSocketServerFactory(u"ws://127.0.0.1:9000")
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factory.protocol = StreamingHashServerProtocol
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listenWS(factory)
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reactor.run()
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