date-> getTimestamp是否返回该日期的00:00:01？

I am checking to see whether current time is inside a specified range but get odd behavior.

I wonder, maybe when I do $end_date->getTimestamp() I get the timestamp for the first minute of that day?

In that case I would need to add (60*60*24)-1 to the timestamp to get 23:59:59 of that $end_date right?

private function check_date_in_range($start_date, $end_date)
{
    //Get current time
    $user_ts = time();

    if ($start_date == null && $end_date == null) {
    //if both are null...           

        return 1;
    }
    elseif ($start_date != null && $end_date != null) {
    // if none is null

        //Convert dates to timestamp for comparison
        $start_ts = $start_date->getTimestamp();
        $end_ts = $end_date->getTimestamp();

        // Check that current date is between start & end otherwise return FALSE.
        return (($user_ts >= $start_ts) && ($user_ts <= $end_ts));

If you want to test for the inclusive range, you would indeed need to add one more day:

$now = new DateTime();

$end_date_next = $end_date;
$end_date_next->modify('+1 day');

return $now >= $start_date && $now < $end_date_next;

Or just use string based comparison on just the date portion instead:

$now = date('Y-m-d');

return $now >= $start_date->format('Y-m-d') && 
    $now <= $end_date->format('Y-m-d');

You can do direct comparisons of DateTime objects, so something like this should work:-

/**
 * @param DateTime $start_date
 * @param DateTime $end_date
 * @return bool
 */
private function check_date_in_range(\DateTime $start_date, \DateTime $end_date)
{
    if ($start_date == null || $end_date == null) {
        //if either is null bail.
        return false;
    }
    $currDate = new \DateTime();
    $start_date->setTime(0, 0, 0);
    $end_date->setTime(23, 59, 59);

    // Check that current date is between start & end otherwise return FALSE.
    return ($start_date < $currDate && $currDate < $end_date);
}

You should realise too, that returning 1 can seem the same as returning true if you are using loose comparisons (==) in PHP.