I'm currently developing an app which uses facebook Open graph API. Using
localhost works fine with facebook authentication but when you want to use graph
api then facebook needs access to the webpage, so that it can parse open graph
meta tags.
The solution to this problem is either deploy your app online or allow localhost
tunneling so that facebook can access it. I prefer localhost tunneling when
working in my development environment.
I use ngrok [https://ngrok.com/]. ngrok securely exposes
