How can I programmatically log in to google+?

Google+ is cool, sadly it lacks an official API.

However, I was able to reverse engineer the protocol used to retrieve the feed that a logged in G+ user gets. The URL to use is this:

[https://plus.google.com/_/stream/getactivities/?&sp=1,2,null,null,null,10,null,\"social.google.com\",[]]

This gives you a nice JSON response containing all feeds that you get in G+ web interface.

However, the problem is that this URL only works correctly if you have already authenticat开发者_开发知识库ed with your google account and you are able to set cookies properly. Otherwise the feed is empty.

The question is: how do I get the authentication cookie from outside of the browser (e.g. from a desktop client)?

I have tried multiple things, for example this (appending oauth_token to the request URL), but nothing works.

Any ideas?

Janusz