content
Subscribe/publish message graph:
Redis publish and subscribe (pub/sub) is a message communication mode : the sender (pub) sends messages, and the subscribers (sub) receive messages - the attention system of WeChat and Weibo
Redis clients can subscribe to any number of channels
Subscribe/publish message graph:
- message publisher
- channel
- message subscriber
The following figure is the channel channel1, and the relationship between the three clients that subscribe to this channel - cilent2, cilent5 and cilent1
When a message is sent to channel channel1 through the Publish command, the message will be sent to the three clients that subscribe to it
Order
Common commands for redis publish and subscribe:
| serial number | Command and Description |
|---|---|
| 1 | PSUBSCRIBE pattern [pattern ...] Subscribe to one or more channels matching the given pattern. |
| 2 | PUBSUB subcommand [argument [argument …]] View subscription and publishing system status. |
| 3 | PUBLISH channel message sends information to the specified channel. |
| 4 | PUNSUBSCRIBE [pattern [pattern ...]] Unsubscribe from all channels for the given pattern. |
| 5 | SUBSCRIBE channel channel ...] Subscribe to a given channel or channels for information. |
| 6 | UNSUBSCRIBE [channel [channel ...]] means to unsubscribe from the given channel. |
test
Subscription information:
127.0.0.1:6379> SUBSCRIBE gh # 订阅一个频道 gh
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "gh"
3) (integer) 1
# 等待推送消息
1) "message" # 消息
2) "gh" # 哪个频道的消息
3) "hello,word" # 消息的具体内容
1) "message"
2) "gh"
3) "hello,redis"
sender:
127.0.0.1:6379> PUBLISH gh "hello,word" # 发布者发布消息到频道
(integer) 1
127.0.0.1:6379> PUBLISH gh "hello,redis"
(integer) 1
127.0.0.1:6379>
scenes to be used:
1. Real-time message system!
2. Fact Chat! (The channel acts as a chat room, just echo the message to everyone!)
3. It is possible to subscribe and pay attention to the system!
For slightly more complicated scenarios, we will use the message middleware MQ