Support custom package index backends

[EnTeQuAk]

• Make backends configurable per project basis
• Ensure security, avoid leaking on projects not having the backends configured
• Define preferred repository to avoid package conflicts (can later be extended to a resolving UI)
• Validate the backend to support the PyPi XML-RPC methods
• Implemend find-links -> Allow for find-links #3

Did I miss anything?

[jaap3]

Note that some people run package indexes that besides serving private packages also mirror/proxy the actual PyPI.

paging @jezdez, he knows about these things...

[EnTeQuAk]

Yepp, already have that in mind as I also run some proxys/mirrors myself. But thanks for the hint!

[jaap3]

Maybe specify which "action"s in the changelog xmlrpc method you are looking for?

[EnTeQuAk]

Well, we are not just calling the changelog but also gathering specific information about the releases via the XML-RPC Api.

So basically we should check for complete xmlrpc support. Besides that there is always the possibility to check the index manually but I don't think that this is a good alternative