Subscribe/publish message of redis

Redis publish and subscribe (pub/sub) is a message communication mode:发送者(pub)发送消息，订阅者(sub)接收消息。

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

actual case

The following example demonstrates how publish and subscribe works. In our example, we created a subscription channel called 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, and subscribers can receive the messages.

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 runoob.com"

(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 runoob.com"

Redis publish and subscribe commands

The following table lists the commonly used redis publish and subscribe commands: