Twitter sign in/login button implementation on web app? How to integrate if Twitter does not provide user email? -

Twitter sign in/login button implementation on web app? How to integrate if Twitter does not provide user email? -

i'm trying implement "sign in twitter" button on web application. upon authentication receive users' credentials not include user email address. twitter not provide user email addresses , i've heard people utilize twitter unique id identify distinct users.

my application allows traditional mode of registration (user creates business relationship us) sign in facebook. in order determine in database whether user exists utilize email address provided under these 2 sign in methods, twitter not allow that.

sure, inquire email address first time sign in twitter poses number of security concerns, example, user may provide person's email address.

the question is, how can i, unique twitter id or other info provided twitter, determine, short of asking email address, if user exists in database?

i've seen people puzzled on fact twitter sign in credentials not include email address?

i appreciate ideas on how solve this.

thank you.

twitter login