<!-- Collection of code snippets by Arne Vajhøj -->
<!-- posted to eksperten.dk, usenet and other places (2002-now) -->
<?php
function dump($ts) {
    echo date('Y-m-d H:i:s', $ts) . "\r\n";
}

$s = '2017-08-01T15:10:00';
dump(strtotime($s));
dump((new DateTime($s))->getTimestamp());
dump(DateTime::createFromFormat('Y-m-d?H:i:s', $s)->getTimestamp());
?>