重塑Redis删除过期时间（删除redis过期时间）

Recent years have been a period of significant growth in the use of Redis, a popular data structure store. Redis is a versatile tool that can be used to store various pieces of information, including key-value caches, user session data and text files. However, one of the challenges associated with using Redis is managing the expiration of objects stored in the database. If objects are not regularly cleaned up, they may continue to occupy valuable storage space and can even become difficult to remove in some instances.

One strategy for managing expired objects in Redis is to make use of expiration hooks. Using expiration hooks, you can define a function that will execute whenever an object reaches its predetermined expiration time. Within this function, any necessary post-expiration tasks can be performed, such as notifying the user about the status of the object, logging the expiration in a database, or deleting the object from the database.

To implement expiration hooks in Redis, use the EXPIRE command. This command sets TTL, or time-to-live, on an object. TTL represents the amount of time, in seconds, until an object expires. You can use the EXPIRE command to set the expiration date on an object, and the EXPIREAT command to set a specific date and time for the expiration. Once the expiration has been set, use the EVALSHA command to define a function that will be triggered when the expiration time is reached. The EVALSHA command takes a SHA1 hash of the Lua script code and executes it when the expiration time is reached.

The following example defines a Redis Lua script that will delete the object from the database when it expires. This example assumes that the key of the object is stored under the name “mykey”.

“`lua

local key = ‘mykey’

local expiration = redis.call(‘TTL’, key)

if expiration

redis.call(‘DEL’, key)

end

Once this script has been defined, use the EVALSHA command to register the Lua script with Redis and set the expiration time on the object. This command takes the SHA1 hash of the Lua script code and the TTL in seconds as arguments. 

redis> evalsha 1

Once the expiration time has been set, Redis will automatically execute the delete command when the object expires. This provides a way to easily manage the expiration of objects stored in the Redis database and frees up valuable storage space in the process. 

Overall, managing the expiration of objects stored in Redis is an essential part of managing a Redis database. Using expiration hooks and Redis Lua scripts, you can easily manage the deletion of objects that reach their expiration time. This allows you to keep your Redis database clean and organized, as well as freeing up valuable storage space.