Can I set the file key for direct s3 uploads?

Hi - I have a very simple use case (perhaps too simple for Shrine, I’m not sure) - I want to upload a file to an s3 bucket using a presign endpoint. (I do not want to attach the file to a model, I just want to upload it)

I’ve got it all set up and working with Uppy on the front end and a Shrine presign endpoint on the backend, but my uploaded files have random hashes for their file keys instead of their original filenames. Ideally I would like to be able to set a prefix and have the file key look like /my/prefix/original_filename.ext or something like that.

I have been reading about the pretty_location plugin, but it looks like that will programmatically assign the keys, I want to have some control over the key.