How to uniquely identify user logging in via oauth?
oauth, oauth-2.0, openid
Solution
You can't get information about the user by the OAuth protocol itself, however, there is normally an endpoint, to which you can make a request, that provides user information. For example Google provides one: after you receive your token, you can make a request to:
GET https://www.googleapis.com/plus/v1/people/me?access_token={TOKEN}
This will return a JSON object containing information about the user, including an unique identifier.
Problem
I particular - I don't understand how to link user that authenticated using oauth to a particular account in my application? So here's accounts in my applciation: ``` CREATE TABLE accounts ( id BIGINT NOT NULL AUTO_INCREMENT, username VARCHAR(40), email VARCHAR(256), created DATETIME, updated DATETIME, PRIMARY KEY (id), UNIQUE KEY (email), UNIQUE KEY (username) ) ENGINE=InnoDB CHARACTER SET utf8 COLLATE utf8_general_ci; ``` With openid for example there is a unique user id (uri, xri) which uniquely identifies that user. So I can just link to my accounts like this: ``` CREATE TABLE openid_logins ( id BIGINT NOT NULL auto_increment, fk_accounts_id BIGINT NOT NULL, openid_identity TEXT NOT NULL, /*that's unique user id*/ openid_provider_url VARCHAR(255) NOT NULL, /*flickr, yahoo, live_journal*/ PRIMARY KEY (id), INDEX (openid_identity), FOREIGN KEY (fk_accounts_id) REFERENCES accounts(id) ON UPDATE CASCADE ON DELETE CASCADE ); ``` So Whenever user logs in via openid -> I can get his regular account referencing fk_accounts_id. But when it comes to oauth - AFAIK there is no such things as oauth_identity_string... And since oauth tokens might change tokens by themselves cannot be used as a unique link to profile in my applicaiton..... So what should I do? How to uniquely identify a user logging in via oauth?