Cookbook Example
How can I...?
Example 4: Building some reliability into the system (Simple Reliable Multicast). Idea is to show layering of protocols. Components used: component, ReadFileAdaptor, VorbisDecode, AOAudioPlaybackAdaptor, Multicast_transceiver, pipeline, SRM_Sender, SRM_Receiver
#!/usr/bin/python
from Axon.Component import component
from Kamaelia.ReadFileAdaptor import ReadFileAdaptor
from Kamaelia.vorbisDecodeComponent import VorbisDecode, AOAudioPlaybackAdaptor
from Kamaelia.Internet.Multicast_transceiver import Multicast_transceiver
from Kamaelia.Util.PipelineComponent import pipeline
from Kamaelia.Protocol.SimpleReliableMulticast import SRM_Sender, SRM_Receiver
file_to_stream = "/usr/share/wesnoth/music/wesnoth-1.ogg"
class detuple(component):
def __init__(self, index):
super(detuple, self).__init__()
self.index = index
def main(self):
while 1:
if self.dataReady("inbox"):
tuple=self.recv("inbox")
self.send(tuple[self.index], "outbox")
yield 1
class blockise(component):
def main(self):
maxlen = 1000 # Needs to be parameterisable
buffer = ""
while 1:
if self.dataReady("inbox"):
buffer = buffer + self.recv("inbox")
if len(buffer) > maxlen:
send = buffer[:maxlen]
buffer = buffer[maxlen:]
else:
send = buffer
buffer = ""
self.send(send, "outbox")
yield 1
#
# Server with simple added reliabilty protocol
#
pipeline(
ReadFileAdaptor(file_to_stream, readmode="bitrate", bitrate=400000, chunkrate=50),
SRM_Sender(),
blockise(), # Ensure chunks small enough for multicasting!
Multicast_transceiver("0.0.0.0", 0, "224.168.2.9", 1600),
).activate()
#
# Client with simple added reliability protocol
#
pipeline(
Multicast_transceiver("0.0.0.0", 1600, "224.168.2.9", 0),
detuple(1),
SRM_Receiver(),
detuple(1),
VorbisDecode(),
AOAudioPlaybackAdaptor(),
).run()
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