Building a list of files in media folders (npvr Music and Videos)

[bgowland]

I'm in to minds about how to provide access to Music and Video folders in nDroid and it seems like I have two options...

1. Simply provide a list of top-level folders and when a user selects one, contact the nDroid service and get it to return a list of items (folders / media files) in that folder.
   
2. Pre-process the entire folder tree and compile a list of paths to media files which nDroid maintains in a DB on the device.
   

The first option possibly requires less coding at the service end as it simply takes a path and enumerates its current contents providing a 'flat' rather than nested data structure. The downside is more network activity and slower navigation to the required media files.

The second would mean potentially very quick navigation in the nDroid app but requires a more complex recursive directory scan to produce a database of information (using the term 'database' generically). I've also never coded anything which does this sort of recursion on folder sub-trees.

Just looking for any comments / hints / advice.

Cheers,
Brian

[imilne]

Getting a list of files over the network (for 1) isn't that slow. It's multiple requests for 'something' over the network that slows things down. You could ask for a list of all files and folders in a directory containing hundreds of elements (one request) in pretty much the same time as you could ask the remote server if a single file existed in some path.

Going with 2 will be faster, but is more complicated. You need to decide how to deal with changes to the file system (the user adding or removing stuff). Do you force them to rescan manually or detect it somehow? If/when a rescan is needed, it could take a *long* time if they have a complicated folder structure. The recursion required is simple though.

.Net4 has some nice stuff in it that would speed up 1 too, but well, you know...

Iain

[bgowland]

Thanks Iain, still spinning this around in my head.

The first approach is basically just how the npvr Music/Video plugins work as far as I can tell. My only issue with that is if a user has a deep tree (lots of simple steps down the tree but multiple network requests) or if they have an insane number of files (1000s) in a particular folder - unlikely but a potentially massive return of data required.

I'm leaning towards the second approach after some experiments. I don't have too many files in either my music or video folders (a few thousand) but recursive searches are pretty quick although without any metadata at the moment. The nDroid service already tracks some file system changes with code I've already got for other things so that's a bonus.

Thanks for the comments - I'll mull it over some more.

Cheers,
Brian