未读消息借助Redis传递（未读消息 redis）

Nowadays, with the further development of network technology, the requirements for real-time information transmission and communication are becoming higher and higher. As a result, the “unread” message service which is convenient and fast has become an important part of many online applications. How to implement such a service in a practical way? In this article, I will share a way to implement the “unread” message service using Redis.

Redis is a powerful and fast memory database, which is excellent in traversing and computing large amounts of data in memory. Redis is especially suitable for situations that require caching and real-time processing such as the “unread” message service, so it can fully meet our needs.

The principle of real-time transmission of “unread” message service depends mnly on the following three steps.

First, set the expiration time of the messages in Redis. We can use Redis’s expiration feature to set a “window of time” when the message is valid, thus ensuring that the message is delivered in a timely manner.

Second, use listen and notify functions to track the message sending status. When a message is sent, the sender will bind the channel of send success in Redis and indicate the related sending status when the message is read.

Third, send number of unread messages in real time. When an event occurs, Redis will publish the unread message channel message to trigger the count and the number of unread messages will be updated in a timely manner.

In addition, some other tools or libraries can be used in the development of “unread” message service, such as redis-cluster for cluster deployment, redis-sentinel for high avlability of redis and so on.

Finally, below is an example written in Java to demonstrate the above implementation process:

import org.springframework.data.redis.core.StringRedisTemplate;

public Object unreadMsg(Integer userId)

{ String clientId = “client ” + userId;

// Set expiration time stringRedisTemplate.expire(clientId, 30, TimeUnit.MINUTES); // Listen and notify StringRedisTemplate.listen(clientId, (ChannelTopic topic, Message message) ->

{ // Get information of the message Object messageInfo = message.getBody(); // Update the number of unread message for the user StringRedisTemplate.opsForValue().increment(clientId); // Set the notification of the message sender to indicate successful transmission StringRedisTemplate.publish(clientId, “1”); });

// Get real-time number of unread messages long unreadMsg = StringRedisTemplate.opsForValue().get(clientId); return unreadMsg;

}

This is just a simple example. With more powerful Redis functions, we can develop more powerful “unread” message services. This article gave an introduction to the “unread” message service implemented based on Redis. I hope it can help.