<?php
/**
* Validates HTML5 week string according to
* https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#weeks
*/
class HTMLPurifier_AttrDef_HTML5_Week extends HTMLPurifier_AttrDef
{
const REGEX = '/^
(?P<year>\d{4,})
-W
(?P<week>[0-5]\d)
$/xi';
/**
* @param string $string
* @param HTMLPurifier_Config $config
* @param HTMLPurifier_Context $context
* @return bool|string
*/
public function validate($string, $config, $context)
{
$string = $this->parseCDATA($string);
if (!preg_match(self::REGEX, $string, $match)) {
return false;
}
$year = (int) $match['year'];
$week = (int) $match['week'];
if ($year <= 0) {
return false;
}
// ISO-8601 specification says that December 28th is always in the last
// week of its year.
// https://en.wikipedia.org/wiki/ISO_8601#Week_dates
$time = mktime(0, 0, 0, 12, 28, $year);
if ($week < 1 || $week > date('W', $time)) {
return false;
}
return $string;
}
}