Redis 发布订阅
redis作为一个pub/sub server，在订阅者和发布者之间起到了消息路由的功能。订阅者可以通过subscribe和psubscribe命令向redis server订阅自己感兴趣的消息类型，redis将消息类型称为频道(channel)。当发布者通过publish命令向redis server发送特定类型的消息时。订阅该消息类型的全部client都会收到此消息。这里消息的传递是多对多的。一个client可以订阅多个 channel,也可以向多个channel发送消息。
终端A：
127.0.0.1:6379> subscribe comments
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "comments"
3) (integer) 1
终端B:
127.0.0.1:6379> subscribe comments
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "comments"
3) (integer) 1
终端C：
127.0.0.1:6379> publish comments good!
(integer) 2
终端A:
127.0.0.1:6379> subscribe comments
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "comments"
3) (integer) 1
1) "message"
2) "comments"
3) "good!"
终端B：
127.0.0.1:6379> subscribe comments
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "comments"
3) (integer) 1
1) "message"
2) "comments"
3) "good!"
可以使用psubscribe通过通配符进行多个channel的订阅