时间戳：检查是否已有30分钟

Question

I have setup this code, and it does not seem to be working. Basically I put a timestamp in the database, and whenever someone tries to submit something, I check their IP and then the last time they submitted with the timestamp Basically I need to make sure that it has been MORE that 30 minutes before they can post. Here is the code I have soo far...

$ip = $_SERVER["REMOTE_ADDR"];
$chkquery = "SELECT * FROM faucet where ip='$ip' ORDER BY timestamp DESC LIMIT 1;";
$chk = mysql_query($chkquery) or die($chkquery."<br/><br/>".mysql_error());
while($row = mysql_fetch_array($chk, MYSQL_ASSOC)){
    $timestamp = $row['timestamp'];
}
$timenow = time();
$chktime = strtotime($timestamp);
if($chktime <= ($timenow - 1800)) {
    echo "Yay! It has been 30 minutes!";
} else {
    echo "Wait! Its not been 30 minutes";
}

Is there anything I need to change/fix to get this to work? Thanks a lot for the help! The if statement might be reversed, but IDK, and also I end up with Yay! no matter what time it is...

Answer 1

It is not safe to rely on strtotime() as it is defined by the system's timezone settings. You should adjust date.timezone setting or use the date_default_timezone_set() for example:

date_default_timezone_set('America/New_York');
...

if($timenow - $chktime >= 1800) {
    echo "Yay! It has been 30 minutes!";
} else {
    echo "Wait! Its not been 30 minutes";
}

EDIT: add the remaining time

$time_diff = $timenow - $chktime;
if( $time_diff >= 1800) {
    echo "Yay! It has been 30 minutes!";

} else {
    $remaining = (1800 - $time_diff );
    echo "Wait! Its not been 30 minutes
";
    echo "please come back in ".date ( "i:s" , $remaining)." minutes";
}