requests. The internal representation of post-arguments is String and
therefore not appropriate for byte[] object as submitted by file pushes.
Therefore all pushed files are encoded to base64 _after_ uploading with
an http form (you do not need to do that encoding yourself) to hand-over
the byte[] as string in the post argument.
Servlets which read such files must decode the base64 data to get the
original byte[] array.
This is considered as a temporary solution for file uploads and a proper
implementations would need to consider all attributes as handed over as
Objects with either String or byte[] Object instances. This would be a
major code change and is not done at this time here now. The feature was
submitted to realize a feature as pushed with the next commit.