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publish_subscribe.py
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92 lines (66 loc) · 1.98 KB
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Reference: http://www.slideshare.net/ishraqabd/publish-subscribe-model-overview-13368808
Author: https://github.com/HanWenfang
"""
class Provider:
def __init__(self):
self.msg_queue = []
self.subscribers = {}
def notify(self, msg):
self.msg_queue.append(msg)
def subscribe(self, msg, subscriber):
if msg not in self.subscribers:
self.subscribers[msg] = []
self.subscribers[msg].append(subscriber) # unfair
else:
self.subscribers[msg].append(subscriber)
def unsubscribe(self, msg, subscriber):
self.subscribers[msg].remove(subscriber)
def update(self):
for msg in self.msg_queue:
if msg in self.subscribers:
for sub in self.subscribers[msg]:
sub.run(msg)
self.msg_queue = []
class Publisher:
def __init__(self, msg_center):
self.provider = msg_center
def publish(self, msg):
self.provider.notify(msg)
class Subscriber:
def __init__(self, name, msg_center):
self.name = name
self.provider = msg_center
def subscribe(self, msg):
self.provider.subscribe(msg, self)
def run(self, msg):
print("{} got {}".format(self.name, msg))
def main():
message_center = Provider()
fftv = Publisher(message_center)
jim = Subscriber("jim", message_center)
jim.subscribe("cartoon")
jack = Subscriber("jack", message_center)
jack.subscribe("music")
gee = Subscriber("gee", message_center)
gee.subscribe("movie")
fftv.publish("cartoon")
fftv.publish("music")
fftv.publish("ads")
fftv.publish("movie")
fftv.publish("cartoon")
fftv.publish("cartoon")
fftv.publish("movie")
fftv.publish("blank")
message_center.update()
if __name__ == "__main__":
main()
### OUTPUT ###
# jim got cartoon
# jack got music
# gee got movie
# jim got cartoon
# jim got cartoon
# gee got movie