Validate string input for DateTime::modify()

Question

I have as scenario where the $string variable sent to DateTime::modify($string) is read from a database edited by users, how can i validate that $string is a proper string for DateTime::modify() ?

Answer 1

You could do something like this, and call it before you pass the string into your actual date:

function modifyIsValid($modifyString) {
    $d = new DateTime();
    $isValid = $d->modify($modifyString);

    if ($isValid === false) {
        return false;
    }

    return true;
}

->modify() returns false is the string passed is not valid, although it will also throw up an E_Warning which is not ideal.

$d = new DateTime();
$string = 'not a valid modifier';

if (modifyIsValid($string)) {
    // Continue 
}  else {
    // Print a friendly error message.
}

You can find more information about it in the manual: http://php.net/manual/en/datetime.modify.php

Hope it helps.