tp5 _initialize not logged into the controller initialization and prohibit login and repeat

After the first to write a file to build a public profile Base.php when configured Base inherited the controller and other controllers can be directly inherited Base

code show as below  

The following code is the main page, and find isLogin method by which to judge whether the login method, unknown then forced to return to the login page

                                           

Here is the code to enter the login page, and find whether the login was detected before existLogin users, such as user has landed, then following the prompts and enter the main page