Re: GSoC 2011: Synchronizing F-Spot data

[Sven Utcke <sven utcke gmx de>]

Hello Simon,

> > Now I need to find a mentor.

If you are looking for one on this list, you might want to clarify
what the requirements for / expectations of a mentor are...

>  * Some notes on why I consider Flickr, Amazon S3 and Conduit
>    problematic for implementing this particular task.

I'll add my comments on that below

> In my particular case, I want to browse and edit my images on my
> main computer, which is a desktop. When traveling I only have my
> laptop with me and thus I do not currently have access to my F-Spot
> database. A workaround is to copy the database between the
> computers, but that is tedious and error prone. This project aims to
> solve this problem by introducing a synchronization solution capable
> of synchronizing the F-Spot data model in its entirety across
> multiple F-Spot installations.

So in your usecase, no two people will work with the same data
concurrently.  Doesn't that mean you could simply sync the DB,
provided the photos are already stored offline?  So all you need is
some conflict resolution on the DB (fairly easy, as the DB can be
converted to text and back to Sqlite3 format without loss of
information), and possibly some local caching, right?

> It would also be nice if it could
>  * support additional data that might be added by addins
>  * support lightweight transfer of on-file metadata changes
> It might be too much to implement those last two things this summer though.

Well, the latter, at least, ought to be quite easy.  Although it
either requires a complete download (and, worse, upload) of the file,
or a machine running some server-software, which I sort of dislike,
see below...

> I have looked at some different approach to the problem, including
> using a web based storage service like Amazon S3 or a Flickr Pro
> account, but those kinds of approaches will probably make it hard to
> handle the F-Spot-specific parts of the metadata, like versions and
> the tag tree.

I really sort-a like the idea of using flickr or any other
webstorage.  The problem, of course, is that this would not allow for
partial updates of the files (never mind whether we are talking
metadata or photos).  Still, it would be quite nice.

> Therefore, my current thinking is that I will implement this as a
> remote repository of the F-Spot data that support pushing and
> pulling data to/from the repository and also some extra
> functionality to simplify synchronization.  To communicate with the
> server an XML-based REST api will be used. XML makes it easy to
> integrate XMP metadata, which I believe will cover much of the
> per-image data. An addin to F-Spot keeps the local F-Spot database
> up to date with the server so that F-Spot can continue to use the
> already existing queries, and load images quickly from the local
> harddrive. This addin will also track changes to the data and manage
> synchronizing the changes back to the server.

In my estimate, the by far easiest way to achieve your particular goal
under those particular constraints (no concurrent access) would be to
find a server running unison and be done (but I did mention that,
didn't I :-)

So if you aren't going that way, it might be worth adding some extra
functionality justifying the overhead.

>  * mhutch suggested that a concept like catalogs in Lightroom might
>    be useful.  Basically, this would be a way to only sync selected
>    pictures.  It could be implemented as a tag query, to tie in to
>    existing F-Spot concepts.

Makes sense.  So there's some extra functionality at least.

>  * Partial local cache. Perhaps this overlaps a bit with the above,
>    but it transform the local pictures folder into a cache
>    containing the most recently used files. Reduces initial
>    bandwidth requirements and used storage space.

Did I mention I'm all for that?  Although, so far I'm not clear
whether your original plan was to store all photos _only_ offline, o
whether to store copies of all photos on the server and all clients (I
had guessed the latter, but maybe erroneously).

Sven
-- 
  .xxxx.       FACE-Tools                                      |||||
 |(o)(o)|      http://www.svenutcke.de/sw/Face/              {. @ @ .}
(  (__)  )                                                    |  o  |
  | __ |       Face detection and recognition                  \_U_/
   \__/        for photo-managers like F-Spot