Alert if document is already open by another user on server

Hi

First off, I know working off servers isn't the best practice because who knows if someone else is making changes to the very file you're supposed to be working on. However, we work directly from our server and the biggest concern is two users both opening and saving changes without being aware they're overwriting another persons work.

Is it possible to run a script upon file open to:

1. check the metadata of the file

2. alert the current user if this is open by someone else, and if this isn't true then to update the metadata to say which user has it open.

File close:

1. remove user information from metadata, so next user opening will not be falsely alerted

A while ago I had some joy with step 1, however step 2 required another save of the file otherwise it's metadata wasn't being picked up by the next user. This in turn meant longer working times because the file would open, then save instantly if it didn't find another users name in the metadata.

Is writing to a log file on the server a better solution which does not require the psd/tiff/eps to be resaved once the curent users info is stored in it?

If this is a better idea is there a way to write into this log, that should Photoshop crash and the regular close script that cleared the log didnt work so to now clear it upon process termination?

Simply put, I want an alert to popup when a file is open by someone else. where this queries the files status or looks at tags placed in the file when i use?

Thanks,

Tom

EDIT: FYI i was using IPTC data store the in use or not in use tags with if clauses containg either alert or save methods.

Message was edited by: thomas.f.elton