on my server I host my personal git remote-side projects (with gitosis), and I have built a web interface to browse the repositories (something like Github).
On the remote-side, you are not allowed to do a lot of stuff, because a working tree is missing, and this is correct: btw, for a repository explorer, with few commands I can do almost everything.
Except for git blame.
I'm not able to find out how to blame a file without a working tree, within the remote-side repository. Got you some ideas?
The following should work even in bare repositories:
git blame <rev> -- <path>
E.g.
git blame master -- README.txt