i hope it closes #63, could not test it against a real index that requires authentication

I am against this kind of large code change if it cannot be tested at all. This probably conflicts heavily with #82 and I'd rather have this code here follow a similar pattern regarding the class structure.

@shamilbi if you still need authentication with the rework in #82 we probably should discuss redesigning this PR.
Like creating a centralised HTTP access, resolving credentials by URL (as artifacts can be on a different host, like a CDN) and adding tests for it.

If you don't need, we might want to close the PR for now.