fair enough, if you want something unit tested i can just write a test or two for you rather than adding to your confusion by givin you my own crappy explanation on ut.
regarding uploadify, which i had read about before: i tried it out and it's just great ! would be nice to decouple it from DOM (falling back to TreeDropdown if SimpleTreeDropdown doesn't exist) so one could use it on it's own.
Here are some things that fail frequently in Uploadify:
- Malformed path to the upload script, returns a 404
- Flash is unable to pass the session to the controller through $_REQUEST['PHPSESSID'] (probably a hard one to test)
- File doesn't respect the given upload folder, whether chosen by the user, or stated in the code with setUploadFolder();
- File doesn't save into containing DataObject properly. (When reloaded for editing, the files are no longer there)