Redis publish and subscribe

Redis publish and subscribe (pub/sub) is a message communication model: the sender (pub) sends messages and the subscriber (sub) receives messages.

Redis clients can subscribe to any number of channels.

The following figure shows the relationship between channel channel1 and the three clients that subscribe to this channel - client2, client5 and client1:

When there is a new message through the PUBLISH command When sent to channel channel1, this message will be sent to the three clients that subscribe to it:

Example

The following example demonstrates how publish and subscribe works. . In our example, we created a subscription channel named redisChat:

redis 127.0.0.1:6379> SUBSCRIBE redisChat

Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "redisChat"
3) (integer) 1

Now, we first restart a redis client, and then publish two messages in the same channel redisChat, the subscriber You can receive the message.

redis 127.0.0.1:6379> PUBLISH redisChat "Redis is a great caching technique"

(integer) 1

redis 127.0.0.1:6379> PUBLISH redisChat "Learn redis by w3cschool.cc"

(integer) 1

# 订阅者的客户端会显示如下消息
1) "message"
2) "redisChat"
3) "Redis is a great caching technique"
1) "message"
2) "redisChat"
3) "Learn redis by w3cschool.cc"

Redis publish and subscribe commands

The following table lists the common commands for redis publish and subscribe: