A little background: I've been looking for a tool that would allow me to host my photos from my network at home, but let me search my lightroom database (mainly by date, keyword, metadata, or location) on mobile devices (e.g. iPhone or iPad). There are a lot of services that provide publishing to cloud storage (e.g. Google Drive, icloud, etc.) and have companion apps, but I've found their search capabilities lacking and I'd rather just source the files from home. In my mind what I need is an even lighter weight SQLite database that contains the catalog information I want (and only that info) that I can sync with an app on my phone/tablet. I could also have a directory of very small previews that could also be synced. When I want a file I can select it and various higher resolution versions (up to and including the original file) could be stored in a local cache on the portable device. I could go on, but I think you get the idea.
In order to do this I need this lighter weight catalog file. I was going to write a perl or swift (I'm writing this for OS X) script that used SQLite to pull the relevant data out of my catalog and generate the new mini-catalog, but I figured I should give the Lightroom SDK a shot. I've never developed for Lightroom before and I don't know Lua, but I've got some time to learn. The first thing I thought I should check out was to see if anyone had built a plugin that did what I'm hoping to do. If so I could save a lot of time. I figured this forum would be a good place to check to see if anyone knows of such a plugin. If so, please let me know. I'd much appreciate it. If it's not possible, that would be good to know too.
I doubt there is a way to create a new catalog via plugin (without some serious stunt - i.e. nothing in SDK supports it), and remember - open/active catalog is locked (sql will fail), so you can only do the script if Lr is closed or has a different catalog open.