How to design an account that can only log in with one terminal?

such as title:
my own logic:
1. Add a field is_online to the user table (whether you have logged in 0 but not logged in 1)
2. Determine whether this field is 1 when logging in, and update this field to 0

when you exit.

if the user exits abnormally (closing the browser, etc.), it will be impossible to update the is_online field

at present, I have come up with a method: but I don"t fully understand

.

is to determine whether the session_id in the database exists in the server when session_id is stored in the database and logged in?

how to do this, please ask

Php
Mar.03,2021

each login generates a user user_id and a relative token, to be saved in the database. Determine whether the token is valid before each API request. When the token changes after re-login, the token verification of the previous login is invalid, thus realizing that an account can only log in with one terminal.

after each login, a time-limited token, is generated and saved on both the server and the client, and only this token
is verified each time. After a new login event occurs, due to the change of token, the previous valid login is automatically invalidated

.

when logging in, session_id is stored in the database for authentication to determine whether the session_id in the database still exists in the server

get the directory path of session_id in the server through session_save_path () 

//
if($admin['is_online']) {
    // session_id    session30
    if(file_exists(session_save_path().'\\'.$admin['session_id'])) {
        ajaxmsg('',0);
    }
}

https://github.com/zhangrenji.

our website uses memcache sharing session

jwt

Previous: Why does the arc I draw with SVG work on Android and start at 3 o'clock on the right on IOS?

Next: How does Node socket.io actively push messages to the front end?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1ea8e02-1f14.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1ea8e02-1f14.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?