+ # Authenticates a user by their login name and unencrypted password. Returns the user or nil.
+ def self.authenticate(login, password)
+ u = find_by_login(login) # need to get the salt
+ u && u.authenticated?(password) ? u : nil
+ end
+
+ # Encrypts some data with the salt.
+ def self.encrypt(password, salt)
+ Digest::SHA1.hexdigest("--#{salt}--#{password}--")
+ end
+
+ # Encrypts the password with the user salt
+ def encrypt(password)
+ self.class.encrypt(password, salt)
+ end
+
+ def authenticated?(password)
+ crypted_password == encrypt(password)
+ end
+
+ def remember_token?
+ remember_token_expires_at && Time.now.utc < remember_token_expires_at
+ end
+
+ # These create and unset the fields required for remembering users between browser closes
+ def remember_me
+ self.remember_token_expires_at = 2.weeks.from_now.utc
+ self.remember_token = encrypt("#{email}--#{remember_token_expires_at}")
+ save(false)
+ end
+
+ def forget_me
+ self.remember_token_expires_at = nil
+ self.remember_token = nil
+ save(false)
+ end
+
+ protected
+ # before filter
+ def encrypt_password
+ return if password.blank?
+ self.salt = Digest::SHA1.hexdigest("--#{Time.now.to_s}--#{login}--") if new_record?
+ self.crypted_password = encrypt(password)
+ end
+
+ def password_required?
+ crypted_password.blank? || !password.blank?
+ end
+end