如何拒绝在短时间内发送两次相同的 POST 请求

Question

I am wondering if there is a standard way to reject requests with the same body sent within a few seconds at the API gateway itself.

Forex: Reddit rejects if I try to post the same content within few seconds in a different group. Similarly, if I make a credit card payment for the second time, it automatically rejects it.

I am wondering if there is a way to have the same behavior in the AWS API gateway itself so that we are not handling it in lambda functions with dynamoDB and stuff.

Looking forward to efficient ways of doing it.

Answer 1

The API Gateway currently doesn't offer a feature like that, you'd have to implement this yourself.

If I was to implement this, I'd probably use an in-memory cache like ElastiCache for Redis or Memcached as the storage backend for deduplications. For each incoming request I'd determine what makes it unique and create a hash from that.

Then I check if that hash value is in the cache already. If that's the case it 'sa duplicate and I reject the request. If it isn't already in the cache, I'd add it with a time to live of n seconds (The time interval in which I wish to deduplicate).