[Owncloud] Accessing files outside the users home folder

[Robin Appelman]

Hi,

Trowing some idea out here for whoever is interested and/or wants to provide 
some ideas or feedback.

Currently the only "correct" way of accessing any file of a user, oc_filesystem, 
is limited to files within the users home folder (/username/files in the 
complete virtual filesytem).
While this is fine for most uses, there are plenty of valid cases where an app 
needs to access files outside the home folder. Sharing needs to access files 
owned by other users, gallary needs to store thumbnails of photos and 
galleries and media might want to store album covers somewhere.

All apps that currently need to do something like this currently have their 
own implementation that bypasses oc_filesystem partly of completly, while that 
may work for now, bypassing oc_filesystem would, in the future, mean not having 
things like encryption, metadata storage or not having the file at all due to 
it being mounted from a remote source.

My idea for providing a proper way to access files outside the users home 
folder without making oc_filesystem harder to use for 90% of the use cases is 
to add a new class oc_filesystemview, which can create a "view" into ownCloud's 
virtual file system simular to oc_filesystem, only without having to be locked 
into the users home folder.

Every view can have it's own chroot, giving it access to a part of the 
filesystem and will provide the same functionality oc_filesystem provides.
The sharing app could create a new view on /otheruser/files to gain access to 
the files and application that need to store files outside the users view can 
create a view on /username/appid.

To retain compatibility with the current way of using oc_filesystem, 
oc_filesystem will provide a static default view on /username/files with zero 
api changes for apps using oc_filesystem the "normal" way.

Looking foreward to ideas/feedback on this increasingly relevant topic.

 - Robin Appelman