【Python之旅】第七篇（三）：使用Redis订阅服务
在C/S架构中，可以充分地利用Redis订阅服务，实现服务器端和客户端的信息收发，下面说说在Python中如何使用Redistribute的订阅服务。这里要举的例子是，Server端进行服务的订阅，而Client端进行消息的广播发送。
1.方法一：Server端使用Redis操作+Client端使用Python交互器
（1）Server端
进入Redis操作界面：
xpleaf@xpleaf-machine:/mnt/hgfs/Python/day7/redis-2.8.9/src$ redis-cli
127.0.0.1:6379>
开始监听频道chan_107：
127.0.0.1:6379> SUBSCRIBE chan_107
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "chan_107"
3) (integer) 1
（2）Client端
创建redis_connector.py文件，用以连接Server端Redis：
#!/usr/bin/env python
import redis
r = redis.Redis(host='192.168.1.112',port=6379,db=0)
在Python交互器中导入redis_connector，并发布消息：
>>> redis.r.publish('chan_107','hello my name is xpleaf')
1L
此时在Server端中就能看到Client端发布的消息了：
127.0.0.1:6379> SUBSCRIBE chan_107
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "chan_107"
3) (integer) 1
1) "message"
2) "chan_107"
3) "hello my name is xpleaf"
2.方法二：Server端使用Python程序+Client端使用Python交互器
（1）Server端
程序代码如下：
import redis_connector as redis
channel = 'chan_107' #频道应该要和发布者的一样，否则将无法订阅到发布者发布的消息
msg_queue = redis.r.pubsub() #bind listen instance
msg_queue.subscribe(channel)
while True:
data = msg_queue.parse_response() #waiting for the publisher
print data
可以看到这里也导入了redis_connector模块用来连接本地的Redis数据库，跟Client端的类似，只是IP地址改为'localhost'，如下：
#!/usr/bin/env python
import redis
r = redis.Redis(host='localhost',port=6379,db=0)
msg_queue.parse_response()即是用来响应Client端发布的消息，执行该程序，开始监听消息：
xpleaf@xpleaf-machine:/mnt/hgfs/Python/day7/monitor/m_server/core$ python redis_sub.py
===>光标停在此处，开始监听Client端发布的消息
（2）Client端
创建redis_connector.py文件，用以连接Server端Redis：
#!/usr/bin/env python
import redis
r = redis.Redis(host='192.168.1.112',port=6379,db=0)
在Python交互器中导入redis_connector，并发布消息：
>>> redis.r.publish('chan_107','hello my name is yonghaoye')
2L
>>> redis.r.publish('chan_107','second msg')
2L
上面两步其实和方法一是一样的。
此时在Server端中也可以订阅到Client端发布的消息了：
xpleaf@xpleaf-machine:/mnt/hgfs/Python/day7/monitor/m_server/core$ python redis_sub.py
['message', 'chan_107', 'hello my name is yonghaoye']
['message', 'chan_107', 'second msg']
===>光标停在此处，继续监听Client端发布的消息
3.方法三：Server端使用Python程序+Client端使用Python程序
直接给出Client端的程序代码：
import redis_connector as redis
for i in range(10):
redis.r.publish('chan_107','This is the NO.%s msg I send to you' % i)
Server端开始监听：
xpleaf@xpleaf-machine:/mnt/hgfs/Python/day7/monitor/m_server/core$ python redis_sub.py Client端发布消息：
# python publish.py 在Server端中很快就可以监听到Client端发布的消息：
xpleaf@xpleaf-machine:/mnt/hgfs/Python/day7/monitor/m_server/core$ python redis_sub.py
['message', 'chan_107', 'This is the NO.0 msg I send to you']
['message', 'chan_107', 'This is the NO.1 msg I send to you']
['message', 'chan_107', 'This is the NO.2 msg I send to you']
['message', 'chan_107', 'This is the NO.3 msg I send to you']
['message', 'chan_107', 'This is the NO.4 msg I send to you']
['message', 'chan_107', 'This is the NO.5 msg I send to you']
['message', 'chan_107', 'This is the NO.6 msg I send to you']
['message', 'chan_107', 'This is the NO.7 msg I send to you']
['message', 'chan_107', 'This is the NO.8 msg I send to you']
['message', 'chan_107', 'This is the NO.9 msg I send to you']
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