I'm trying the recent released Facebook Messenger Platform and so far so good. Everything worked well and I was able to create a echo bot.
But I'm wondering how I could identify this user that started chatting in my page. For example, when a user started chatting I get a PID user (page specific user id).
Making the follow request to Facebook Graph API:
GET https://graph.facebook.com/v2.6/{PAGE_SPECIFIC_USER_ID}
I discovered that I can just ask for the following fields: first_name,last_name and profile_pic.
So my question is, how could I discover if this user is a current customer of my business page? Is there another way of querying more information (like e-mail and real facebook user id)?
Currently, there's no way to do this. The best way would be to prompt the user to enter their information in chat or give them a link to a mobile login page or some other way of linking their account to the chat.