Check whether the string is a unix timestamp

Question

I have a string and I need to find out whether it is a unix timestamp or not, how can I do that effectively?

I found this thread via Google, but it doesn\'t come up

Answer 1

As a unix timestamp is a integer, use is_int(). However as is_int() doesn't work on strings, we check if it is numeric and its intergal form is the same as its orignal form. Example:

( is_numeric($stamp) && (int)$stamp == $stamp )

Answer 2

    //if anything else than digits inside the string then your string is no timestamp 
    //in which case maybe try to get the timestamp with strtotime

    if(preg_match('/[^\d]/', $str)) {
        $str = strtotime($str);

        if (false === $str) {
            //conversion failed - invalid time - invalid row
            return;
        }
    }

Answer 3

If you might think to replace this solution with is_numeric(), please consider that php native function provides false positives for input strings like "1.1", "0123", "0xFF" which are not in timestamp format.

Answer 4

In PHP for checking if a timestamp represents a valid Gregorian date this worked for me:

function checkdateTimestamp($timestamp) {
    return checkdate((int)date('m',$timestamp),(int)date('d',$timestamp),(int)date('Y',$timestamp));
}

Answer 5

This doesn't account for negative times(before 1970), nor does it account for extended ranges(you can use 64 bit integers so that a timestamp can represent a value far after 2038)

$valid = ctype_digit($str) && $str <= 2147483647;

Answer 6

or

if ($startDate < strtotime('-30 years') || $startDate > strtotime('+30 years')) {
    //throw exception
}