I was surprised with his answer, as they currently rely on the unity3d market for sales. I don't need to go into the details of why it's a great idea to make a photon-construct2 plugin. They'll come around eventually.
CJR Gaming has been a real life saver with Photon. But it required me to learn a spot of C#.
It's the closest thing I've found to SocketIO.
I have quite a bit of experience with the Photon Server version so if you need some quick answers, that's definitely something I can help with.
Epic Space Online - Google it!