Redis Pub/Sub

Redis publish and subscribe (pub/sub) is a message communication mode: 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 channel channel1 , as well as the three clients that subscribe to this channel —— client2 , and client5 and client1 The relationship between

When a new message is sent to the channel channel through the PUBLISH command1 At this time, this message will be sent to the three clients that subscribe to it:

Online example

The following example demonstrates how publishing and subscribing work, which requires starting two redis-cli client.

In our example, we created a subscription channel named w3codeboxChat:

Now, let's restart a redis client first, and then on the same channel w3codeboxChat publishes two messages, and the subscriber can receive the messages.

The process is as follows:

• Start the local Redis service, start two redis-cli client.

• inthe first redis-cli clientEnter SUBSCRIBE w3codeboxChat, which means to subscribe to w3codeboxChat channel.

• inthe second redis-cli clientEnter PUBLISH w3codeboxChat "Redis PUBLISH test" to w3codeboxChat channel at this time, in the first redis-The cli client will see the message sent by the second redis-Test message sent by the cli client.

Redis Pub/Sub Commands

The following table lists the commonly used redis pub/sub commands: