Currently, I'm using Parse to handle my backend, and I have multiple ways to login -> via regular email/password and via linkedin.
Parse has a specific method of logging in requiring username/password.
If a user registers through linkedin, I hash a combination of his information as his password, and login through parse. (i.e. username: user's linkedin account / password: hashed version of user information).
If a user registers through email, the user sets his own password, logs in through parse (i.e. username: user's email / password: user's predefined password).
There's no way to retrieve a plain text version of the password, so what would be a good way to handle login through linkedin when the user has registered regularly (set his own password), and vice versa?