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This article uses the example code to show several application scenarios of Redis string type, the code is very detailed, which can be used as a reference for interested friends. I hope it will be helpful to you.

Current limit

Redis can be used to limit the current. Redis itself has excellent performance and can be used to fend off some requests.

Defense against heavy traffic

Now website attacks are increasingly rampant, static resources can use cdn, but dynamic programs how to defend. Next, show a redis solution to defend against a large number of requests.

The basic idea is to limit the number of requests in an ip within a certain period of time, for example, the number of requests per second in an ip cannot exceed 10.

The pseudo code is as follows:

Function ip_limit ($cnt = 10) {$ip = $SERVER ['SERVER_ADDR']; $key = "limit:$ip:cnt"; $isExisit = $redis- > set ($key, 1, [' nx', 'ex'= > 1]); if (! $isExisit | | $redis- > incr ($key) set ($key, 1, [' nx', 'ex'= > $time]); if (! $isExisit) {/ / through return true } else {/ / do not pass return false;}}

Store session

Using redis to store session is now the recommended way, its advantage is high performance, automatic expiration ecstasy. (PHP's own session garbage collection mechanism is not reliable, and there is a probability of expiration.)

This method is very simple, as long as you modify the php.ini file.

Find the session.save_handler line and change it to

Session.save_handler = redis

Modify session.save_path to

Session.save_path = "tcp://localhost:6379"

How to set the password for redis, just change it to

Session.save_path = "tcp://localhost:6379?auth=password"

If it is not a stand-alone application, but distributed, how to use redis to centrally manage session?

It's simple, too. Also, as long as you modify the php.ini file. For example, session is centrally managed on 192.168.1.220, and the php.ini files of other machines are modified as follows:

Session.save_handler = redissession.save_path = "tcp://192.168.1.220:6379?auth=password"

The above are several application scenarios of Redis string type. If you encounter this problem in your daily work, I hope you can solve the problem through this article. If you want to know more about it, welcome to follow the industry information channel!

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