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