How to implement rate-limiting on redis?

Question

Redis

Let's say I want to make a limit of 100 requests per day by ip. There are two options to implement rate-limiting. After each request:
1) easy-way : store the key by IP, do incr(), setExpire(currentTime + 1 day);
Pros: easy to implement, don't suffer from performance
Cons: window of 1 day is smeared for several days
2) hard-way : I store all visits, do setExpire for each one individually, count the number of visits using key *. The result is an exact window (1 day).
Pros: hard to implement, performance suffers (?)
Cons: exact window of 1 day, user will be able to make 101 requests after 1 request expires.

Question - 1) how to implement the second option in radish? In my head, there is an option to generate a key like IP:RANDOM_UUID and set expire in 1 day. Then look for the key by IP mask
2) How popular is the second option? Is it possible to put the first and not bathe?

Answer 1

You can store a list of request times, the IP key.

"192.168.15.20": [11, 22, 33, 44],
"192.168.15.22": [10, 24, 35, 42, 46],

Watch its length (< 100 ?), compare the current time with the last one in the list.
Insert the time of the resolved request at the beginning.
A new request arrives. Further pseudocode:

const ip = request.ip;
const ts = Date.now();
const len = Redis.LLEN(ip);

if (len < 100) { // можно 
  Redis.LPUSH(ip, ts);
  return true; // можно выполнять запрос
}

const last_ts = Redis.LRANGE(ip, -1, -1);

if ((ts - last_ts) < 864e5) { // меньше суток
  return false; 
} else {
  Redis.LPUSH(ip, ts);
  Redis.LTRIM(ip, 0, 99);
  return true;
}

And it's probably worth wrapping it all in MULTI .. EXEC, so that parallel requests from one IP to make a mess.