We support uploading of files to a page. This is very similar to having attachment to an email. At this time, the uploaded files are added as children of the page. The upload feature makes use of the with Drag & Drap functionality and with the Browse Button.
However, a complete file manager has to offer the ability to delete files, rename files, move or share files from one page to another (and these features are not yet available).
The visual part of the file manage has to be a Widget (??? I think now that all pages accept attachments and if not then uploads just get refused ???). See:
SourceForge.net has a good example that works well, although it lacks the multi-file support.
The page editor should already give us a way to do so. We can look into IMCE and reuse some or all of that code.
The Browse should work with multiple files also. At this point IMCE only allows you to upload one single file. We can also look into a Virtual Box mechanism where users see their file folder on their computer and can copy/paste files into it. (that last one would be the best assuming we can get very high security on BOTH sides.)
Files mime type must be checked by the server and by default only known formats are accepted (only exception(s) would be all the administrator users who may want to upload other files...)