Example of Session login verification in PHP

Login Copy Code Second, the Login test page @mysql_connect ("localhost", "root", "1981427")//Select the database before you need to connect to the database server Or Die ("Database server Connection Failed"); @mysql_select_db ("test")//Select Database MyDB Or Die ("database does not exist or is not available"); Get user input $username = $_post[' username '); $passcode = $_post[' passcode '); Execute SQL statement to get the value of session $query = @mysql_query ("Select Username, userflag from users" ." where username = ' $username ' and passcode = ' $passcode ' ") Or Die ("SQL statement execution failed"); Determine if the user exists, the password is correct if ($row = mysql_fetch_array ($query)) { Session_Start (); The beginning of the sign session Determines whether the user's permission information is valid, or if 1 or 0 indicates a valid if ($row [' userflag '] = = 1 or $row [' userflag '] = = 0) { $_session[' username '] = $row [' username ']; $_session[' userflag '] = $row [' Userflag ']; echo "Welcome to login, click here to enter the Welcome screen"; } else//If permission information is invalid output error message { echo "User rights information is incorrect"; } } else//If the user name and password are incorrect, the output error { echo "User name or password error"; } ?> Copy Code Third, log off the login page unset ($_session[' username '); unset ($_session[' passcode '); unset ($_session[' Userflag '); echo "Logout success"; ?> Copy Code Four, the successful login prompt page Session_Start (); if (isset ($_session[' username ')) { @mysql_connect ("localhost", "root", "1981427")//Select the database before you need to connect to the database server Or Die ("Database server Connection Failed"); @mysql_select_db ("test")//Select Database MyDB Or Die ("database does not exist or is not available"); Get session $username = $_session[' username '); Execute SQL statement to get Userflag value $query = @mysql_query ("Select Userflag from Users" ." where username = ' $username ' ") Or Die ("SQL statement execution failed"); $row = Mysql_fetch_array ($query); The information in the current database is compared to the information in the session, and if it is different, the session is updated. if ($row [' userflag ']! = $_session[' Userflag ']) { $_session[' userflag '] = $row [' Userflag ']; } Output a different welcome message based on the value of the session if ($_session[' userflag ') = = 1) echo "Welcome administrator". $_session[' username '. " Login System "; if ($_session[' userflag ') = = 0) echo "Welcome user". $_session[' username ']. " Login System "; echo "Logout"; } Else { echo "You do not have permission to access this page"; } ?> Copy Code

