I have a comprehension problem with this Google+ SignIn: https://developers.google.com/+/web/signin/
May I use this as an OpenId for my Homepage with the possibility to set a php session and not just a Javascript token.
Or is this just to get the rights to post or comment on Google+?
Thank you ;-)
Sorry but you can not use the Google+ Sign-in as an OpenId endpoint. It's based on OpenID Connect which is different to OpenId.
You can use Google's OpenID endpoint: https://developers.google.com/accounts/docs/OpenID but you won't have Google+ access.
Or you can use OpenID + OAuth2: https://developers.google.com/accounts/docs/OpenID#oauth but you won't have Google+ access.
Or you can server-side OAuth2Login: https://developers.google.com/accounts/docs/OAuth2Login and ask for Google+'s OAuth2 scopes for access to most features of the Google+ platform.
Or you can just use Google+ Sign-in: https://developers.google.com/+/ This is the recommended solution as it provides client libraries for most major languages and you get access to the full functionality of the Google+ platform.