Example of session logon verification in php

Example of session logon verification in php

Login II. logon detection page @ Mysql_connect ("localhost", "root", "1981427") // you must connect to the database server before selecting a database. Or die ("database server connection failed "); @ Mysql_select_db ("test") // select the database mydb Or die ("The database does not exist or is unavailable "); // Obtain user input $ Username = $ _ POST ['username']; $ Passcode = $ _ POST ['passcode']; // Execute an SQL statement to obtain the Session value $ Query = @ mysql_query ("select username, userflag from users" . "Where username = '$ username' and passcode =' $ passcode '") Or die ("SQL statement execution failed "); // Determine whether the user exists and the password is correct If ($ row = mysql_fetch_array ($ query )) { Session_start (); // indicates the start of the Session. // Determine whether the user's permission information is valid. if the value is 1 or 0, the permission information is valid. If ($ row ['userflag'] = 1 or $ row ['userflag'] = 0) { $ _ SESSION ['username'] = $ row ['username']; $ _ SESSION ['userflag'] = $ row ['userflag']; Echo "Welcome to log on. Click here to enter the welcome page "; } Else // output error message if the permission information is invalid { Echo "incorrect user permission information "; } } Else // if the user name and password are incorrect, an error is returned. { Echo "incorrect user name or password "; } ?> 3. log out of the logon page Unset ($ _ SESSION ['username']); Unset ($ _ SESSION ['passcode']); Unset ($ _ SESSION ['userflag']); Echo "logout successful "; ?> 4. logon success prompt page Session_start (); If (isset ($ _ SESSION ['username']) { @ Mysql_connect ("localhost", "root", "1981427") // you must connect to the database server before selecting a database. Or die ("database server connection failed "); @ Mysql_select_db ("test") // select the database mydb Or die ("The database does not exist or is unavailable "); // Obtain the Session $ Username = $ _ SESSION ['username']; // Execute the SQL statement to obtain the userflag value $ Query = @ mysql_query ("select userflag from users" . "Where username = '$ username '") Or die ("SQL statement execution failed "); $ Row = mysql_fetch_array ($ query ); // Compare the permission information in the current database with that in the Session. if the permission information is different, update the Session information. If ($ row ['userflag']! = $ _ SESSION ['userflag']) { $ _ SESSION ['userflag'] = $ row ['userflag']; } // Output different welcome information based on the Session value If ($ _ SESSION ['userflag'] = 1) Echo "welcome administrator". $ _ SESSION ['username']. "log on to the system "; If ($ _ SESSION ['userflag'] = 0) Echo "welcome". $ _ SESSION ['username']. "log on to the system "; Echo "logout "; } Else { Echo "you are not authorized to access this page "; } ?>