to login using validate with email.

app/models/user.rb

@@ -245,6 +245,8 @@ class User < Principal
     self.read_attribute(:identity_url)
   end
 
+  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-]+(\.[a-z]+)*\.[a-z]+\z/i
+  # VALID_EMAIL_REGEX = /^[0-9a-zA-Z_-]+@[0-9a-zA-Z_-]+(\.[0-9a-zA-Z_-]+)+$/
   # Returns the user that matches provided login and password, or nil
   #登录，返回用户名与密码匹配的用户
   def self.try_to_login(login, password)
@@ -253,7 +255,11 @@ class User < Principal
 
     # Make sure no one can sign in with an empty login or password
     return nil if login.empty? || password.empty?
-    user = find_by_login(login)
+    if (login =~ VALID_EMAIL_REGEX)
+      user = find_by_mail(login)
+    else
+      user = find_by_login(login)
+    end
     if user
       # user is already in local database
       #return nil unless user.active?