Verification code problem under session-thinkphp frame

Framework session Verification Code PHP

Public Function myses () {
Import ("ORG. Util.date ");
$Setime =session (' time ');
$Date =new Date;
if ($Setime!=null) {
$diff = $Date->datediff ("$Setime", "s");
if ($diff >=10) {//Determine if expired
$Setime = $Date->dateadd (= ten, $interval = "s");//Set Expiration time
Session (' Time ', $Setime);//will expire in session
Session (' Rand ', rand (11111,99999));
echo session (' Rand ');
Echo 1111;//session exists, but it takes more than 3 minutes to regenerate the verification code
}
else{
Echo $diff, echo "
";
echo session (' time '); echo "
";
echo session (' Rand '); echo "
";

echo 2222;//3 minutes again to get the output of the indicator
}
}
else {
$Setime = $Date->dateadd (= ten, $interval = "s");//Set Expiration time
Session (' Time ', $Setime);//will expire in session
Session (' Rand ', rand (11111,99999));
echo session (' Rand '); echo "
";
echo session (' time '); echo "
";
The Echo 3333;//session value is not set and a new verification code is generated
}
}

Logic should have no errors, do not know which usage is wrong, because the session is not familiar with, like this by the session to save an expiration time, if the expiration is regenerated. 1, help to change the above code, 2, there is a better way to achieve this function can also

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