Idempotency middleware for Django Ninja (works out of the box, it's plain ASGI)

[violetta98]

Hello everyone!

I got tired of rewriting idempotency in every service and getting it slightly wrong, so I packaged it. Posting here because Django Ninja is ASGI, so this drops in without anything Ninja-specific:

from idemkit import HttpConfig, IdempotencyMiddleware, RedisBackend

# in settings.py ASGI stack, or wrap your application
app.add_middleware(
    IdempotencyMiddleware,
    backend=RedisBackend.from_url("redis://localhost:6379"),
    config=HttpConfig(scope=lambda req: req.headers.get("x-user-id", "anonymous")),
)

A client retrying a POST with the same Idempotency-Key gets the first response back and your handler doesn't run again. Two identical requests at once: one runs, the other waits for its result instead of erroring.

The Django packages in this space are all built on classic WSGI middleware, which is why none of them work here. This one has an ASGI path, so Ninja users aren't stuck writing their own.

It also can run with Postgres, Mongo, DynamoDB, so no need to add Redis just for this.

https://github.com/idemkit/idemkit, Apache-2.0

If it's useful, I'd appreciate a star. It's new, so visibility helps a lot right now.