Common spec/interface for file metadata

[Alexander Larsson]

On Sat, 2005-09-03 at 11:32 +0100, Jamie McCracken wrote:
> Hi,
> 
> Whilst discussing metadata needs for Nautilus, there might be a good 
> case for having a shared metadata interface as there are already a 
> number of metadata frameworks being developed like KDE4's tenor and the 
> Beagle project (as well as my own which I am developing).
> 
> Filemanagers will need to be able to get access to both automatically 
> derived metadata on files as well as user defined ones and it makes 
> sense to use an existing framework if one is already being used for 
> searching/indexing.
> 
> To facilitate this, I would like to propose a simple dbus interface 
> (org/freedesktop/metadata) to allow cross desktop applications to tap 
> into this wealth of information.
> 
> Methods :
> 
> GetFileMetaData
> 	input DBUS_TYPE_STRING s (the file uri)
> 	output DBUS_TYPE_DICT  a{ss} (the metadata)
> 
> SetFileMetaData
>    	input DBUS_TYPE_STRING s (the file uri)
> 	input DBUS_TYPE_DICT  a{ss} (the file metadata)
> 
> 
> The above should be self-explanatory. It would also be handy to have a 
> search method which returns an array of file uris from an input query 
> string but I have no idea what form the input string should take so 
> please make suggestions for this or for anything else.
> 
> If this is deemed good enough and useful enough then I will create a 
> wiki page for it (subject to an FDO admin granting me this).

While such an API is simple and works for some apps its certainly not
gonna be usable for applications like file managers or indexers. Calling
a separate out of process RPC for each file while loading a directory
would totally kill performance. 

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Alexander Larsson                                            Red Hat, Inc 
                   alexl at redhat.com    alla at lysator.liu.se 
He's a maverick pirate astronaut with a robot buddy named Sparky. She's a 
provocative foul-mouthed former first lady looking for love in all the wrong 
places. They fight crime!