PHP script to return a JSON object of observed UPS holidays (i.e. days they don't pick up or deliver) using https://github.com/azuyalabs/yasumi.

ups-holidays.php

<?php

require 'vendor/autoload.php';
$UPS = array(
    "New Year's Day",
    "New Year's Day observed",
    "Memorial Day",
    "Independence Day observed",
    "Independence Day",
    "Labour Day",
    "Thanksgiving Day",
    "Christmas",
    "Christmas observed",
);

$holidays = Yasumi\Yasumi::create('USA', date('Y'));
$official = new Yasumi\Filters\OfficialHolidaysFilter($holidays->getIterator());

$json = "[";

$i = 0;
foreach ($official as $day) {
    if (in_array($day->getName(), $UPS)) {
        if ($i) $json = $json . ",";
        $json = $json .  json_encode($day);
        $i = 1;
    }
}

$NYE_check = Yasumi\Yasumi::create('USA', date('Y', strtotime('+1 years')));
if ($NYE_check->getHoliday('substituteHoliday:newYearsDay')) {
    $json = $json . "," . json_encode($NYE_check->getHoliday('substituteHoliday:newYearsDay'));
}

$json = $json . "]";

echo $json;

?>