Suport File Uploads: Front-end Element

[andrewstec]

As an instructor, I want to be able to select S3 for large file storage on the pl-file-upload element instead of having files automatically saved to the database, so that students can effectively submit large file(s).

Requirements:

• If file is over a particular size, make sure front-end passes information to back-end to store in S3.
• Have option flag in HTML element to enable S3 storage upload
• If a file is successfully selected, display a new HTML element to the user so that the user may upload another file
• Put an option to limit the amount of files
• Create a default limit to the number of files that may be uploaded (5 max.)
• Additional file upload slots are not displayed once they hit their set or default max. limit
• Put a front-end max file-size limit before sending file to the back-end.

[andrewstec]

Notes:

• pl-file-upload.py property appends the unique _file_upload_ string to any filename uploaded through the element. Thus, any pl-file-upload upload can be detected through the index match of the string.

[andrewstec]

Uncertainties:

• Do we want to upload an array of files for each UUID file partition? A file name and contents is already uploaded in an array for some reason. I am guessing this is the approach to go, as we can do one database query to look-up the appropriate files.

[andrewstec]

Note:

• A raw_submitted_answer and submitted_answer are both part of a submission file upload. Both currently get saved to the database. Both raw and submitted versions should either be saved or deleted. At the moment, I will save both of them. We can remove this after if we would like. I am not too sure how likely it would be for an instructor to want both of these files if one of them is modified, but it could happen.