Mitchell_Zemlak16 answered on June 8th 19 at 16:48
put the cookie to the user (once a minute, the cookie in the background updating), somewhere on the server remember that he logged on (type cook updated), if tries to login check is there a record of its authorization and all
cali.Senger99 answered on June 8th 19 at 16:50
From Yii user Dektrium for example there are auth_key, which is used for authorization. Now, under the new login and overwrite the key on a new one, this is equivalent to anlogin with other devices.