Last week I mentioned HyridAuth as an approach for having a single library that wraps social sign ins and services. Almost on schedule I then stumbled across Opauth, which bills itself as a “Multi-provider authentication framework for PHP”.
Source code for Opauth is available at https://github.com/opauth/opauth. That is just the base though, you’ll need a plugin for each service that you want to target ( what Opauth calls a “Strategy” ). There is a long list of available “strategies”, including the standard Twitter, Facebook, Google options.