Increment usage by arbitrary value

[linusrachlis]

Hello all and thanks for the work on this library 👋

I've come up twice against a specific limitation and I was wondering if someone has already considered and rejected this idea, or how difficult you think it would be.

I often find the need to increment the stored value by >1 when calling get_usage(). This happens when trying to protect an API that does something in bulk -- for example, think of an API that would create 2 todo items given the following request:

POST /todos/

[{"name": "foo"}, {"name": "bar"}]

Imagine if creating todos incurs some overhead to the system in proportion to how many individual items are created. In that case, to protect the system, I want to rate-limit this endpoint, but instead of incrementing by 1 for each request, I want to increment by the number of items in the payload.

Naively, it seems like this could be accomplished by:

• adding an optional delta=1 argument to get_usage()
• substituting that argument for the 1 here
• finally, adding the optional delta argument for Django's cache.incr here.

Alternatively, the existing increment argument could be repurposed to a number, though that might be a breaking change.

Regardless, I suggest an implementation only to illustrate for discussion purposes. My main question is, has this already been brought up before? Are you open to a PR doing the above? Are there issues with it that I don't see?

🙏 best wishes