implement password security for files+discussion

(resetting this discussion to focus on new design above.  Old discussion still available via changes tab)

massive progress.

remaining todos here:

1. js needs to handle multiple files / images in a single form

2. √ interface needs to change when file is added

3. √ error handling (above)

4. √ taking name from file (above)

  --Ethan McCutchen.....Tue Dec 13 21:27:48 -0800 2011

in general, I think the use of revision ids is correct, but I think in the cases most likely to be user-manipulated urls, we should use rev (not revision) and it should be the nth revision, not the revision_id.

  --Ethan McCutchen.....Tue Dec 13 21:37:54 -0800 2011

OK, I'm starting to think that we should punt on the issue of being able to handle multiple files/images in a single form until 1.8.2.

Currently files/images are not uploaded until you click submit. This is especially vital on new cards, because files are stored based on revision ids, you can't have a revision id until you've stored a revision, and you can't have a revision without cards.

We're planning to move to a model that will support revisions for unsaved cards. I'll discuss several advantages on that ticket.

The advantages for files/images are

1. this is a much more standard user story and is much better supported by existing libraries

2. relatedly, it will be simple to add some sugar, like upload bars and an upload-from-web option

3. performance will be better, because the image/file will often be uploaded by the time the form is submitted.

  --Ethan McCutchen.....Wed Jan 04 13:41:42 -0800 2012

I guess the question in the meantime is whether there are user stories that make the current behavior unacceptable in the short-term. I don't really know of any. We will probably want to warn wagneers prominently.

  --Ethan McCutchen.....Wed Jan 04 13:43:24 -0800 2012

going to close this. still hearing some issues with specific browsers, filetypes, and migrations, but not using this ticket to track them.

  --Ethan McCutchen.....Wed Feb 01 16:29:33 -0800 2012