Redis publish and subscribe

Redis publish-subscribe (pub / sub) is a messaging mode: the sender (pub) to send a message, subscribers (sub) receive messages.

Redis client can subscribe to any number of channels.

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

When a new message is sent to the channel by channel1 PUBLISH command, this message will be sent to subscribe to its three clients:

Examples

The following example demonstrates how this works publish and subscribe. In our example we have created a subscription channel calledredisChat:

redis 127.0.0.1:6379> SUBSCRIBE redisChat

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

Now, let's re-open a redis client, and then publish redisChat message twice in the same channel, subscribers will be able to 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 w3big.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 w3big.com"

Redis publish and subscribe command

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