Redis: redis message publishing and subscription (understand)

In order to realize the communication of the client , Provides the concept of channel

1.Redis Publish subscribe

Redis Publish subscribe (pub/sub) It's a message communication mode ： sender (pub) Send a message , subscriber (sub) receive messages .Redis Clients can subscribe to any number of channels .

Redis Publish and subscribe diagram

Figure 1 ： Message subscribers (client2 、 client5 and client1) Subscribed Channels channel1：

  Figure 2 ： The publisher publishes messages to the channel channel1, Will be sent to three subscribers ：

 

Redis Common commands for publishing and subscribing

1.subscribe

grammar ：subscribe channel [channel…]

function ： Subscribe to information about one or more channels

Return value ： Subscribed messages

for example ：

 

2.publish

grammar ：publish chanel message

function ： Send the message to the specified channel .

Return value ： Numbers . Number of message subscribers received .

 

  Another client ：

ch1 Just received  

 

 

3.psubscribe

grammar ：psubscribe pattern [pattern]

function ： Subscribe to one or more channels that match the given pattern . Mode with  *  As a wildcard , for example ：news.* Match all to news. The first channel .

Return value ： Subscription information .

because Redis The function of is single , And unstable

It will not be used in actual development , Publish and subscribe to client messages , We will learn a technology that specializes in message communication and publishing