Karman allows to get a file stream this way
InputStream is = s3Provider["bucketname"]["somefile.txt"].inputStream
But is it possible to get a file by an S3 URL? i.e.
InputStream is = s3Provider["bucketname"]["https://s3.amazonaws.com/test-bucket/test/something.png"]
This would allow folders while looking for files. In the above example the folder name is test
If the URL fetching isn't allowed, what is a good way to get files from a folder in a bucket?