How can I simply verify that a username and password are correct with Devise and Rails 3

Question

I am using Devise and Rails 3.

I want to call a function that will simply verify that a user's username and password combination is correct without actually logging in that user. Is there some way I can accomplish something like this with Devise:

User.authenticate(params[:username], params[:password]) 

Answer 1

Get the user out of the database:

user = User.find_by_email(params[:email]) 

Then you can check their password with:

user.valid_password?(params[:password]) 

Answer 2

Or using the one liner:

User.find_by_email(params[:email]).try(:valid_password?, params[:password]) 

which returns true or nil