Add general support for uploading files to the Dioptra Client

[jkglasbrenner]

Overview

The DioptraSession class does not provide built-in support for managing the upload of files. This is necessary to add because different libraries follow different conventions for setting up a file upload, for example the requests library versus the Flask test client. In addition, there are considerations of uploading one versus multiple files and doing streaming uploads for large files. Because of this variety, the interface for uploading files needs to be standardized.

Need to check

• Does a multi-part upload with keys that have relative paths translate into "directories" when the server receives the post?

Relevant Links

• https://flask.palletsprojects.com/en/stable/patterns/fileuploads/
• https://requests.readthedocs.io/en/latest/user/advanced/#post-multiple-multipart-encoded-files
• https://stackoverflow.com/questions/22567306/how-to-upload-file-with-python-requests
• https://toolbelt.readthedocs.io/en/latest/uploading-data.html#streaming-multipart-data-encoder
• https://github.com/pallets/werkzeug/blob/7868bef5d978093a8baa0784464ebe5d775ae92a/src/werkzeug/wrappers/request.py#L200-L231 <- This is the method you'd need to override if you want to implement a fully streamed file upload.
• https://stackoverflow.com/a/42405115 <- Idea for implementing a streaming IO upload.
• https://github.com/pallets/werkzeug/blob/7868bef5d978093a8baa0784464ebe5d775ae92a/src/werkzeug/formparser.py#L133-L192 <- Likely the better way to override the streaming IO functionality.
• https://github.com/pallets/werkzeug/blob/7868bef5d978093a8baa0784464ebe5d775ae92a/src/werkzeug/formparser.py#L368 <- This is the point at which an attached file in an upload actually starts getting pulled down.

Blocks

• WIP: V1 artifact files endpoint changes #658 - This branch needs this functionality before proper tests can be written.

Definition of Done

TBD