php code

add_month.php

    /**
 * 
 * @param \DateTime $date DateTime object
 * @param int $monthToAdd Months to add at time
 */
function addMonth(\DateTime $date, $monthToAdd)
{
    $year = $date->format('Y');
    $month = $date->format('n');
    $day = $date->format('d');

    $year += floor($monthToAdd / 12);
    $monthToAdd = $monthToAdd % 12;
    $month += $monthToAdd;
    if ($month > 12) {
        $year ++;
        $month = $month % 12;
        if ($month === 0) {
            $month = 12;
        }
    }

    if (! checkdate($month, $day, $year)) {
        $newDate = \DateTime::createFromFormat('Y-n-j', $year . '-' . $month . '-1');
        $newDate->modify('last day of');
    } else {
        $newDate = \DateTime::createFromFormat('Y-n-d', $year . '-' . $month . '-' . $day);
    }
    $newDate->setTime($date->format('H'), $date->format('i'), $date->format('s'));

    return $newDate->format('Y-m-d');
}

echo addMonth(new \DateTime('2015-01-30'), 1); //2015-02-28
echo addMonth(new \DateTime('2015-01-30'), 2); //2015-03-30
echo addMonth(new \DateTime('2015-01-30'), 3); //2015-04-30

json_to_csv.php

 /**
     * Export an array as downladable Excel CSV
     * http://stackoverflow.com/questions/155097/microsoft-excel-mangles-diacritics-in-csv-files
     * @param array $header
     * @param array $data
     * @param string $filename
     */
    function toCSV($header, $data, $filename)
    {
        $sep = "\t";
        $eol = "\n";
        $csv = count($header) ? '"' . implode('"' . $sep . '"', $header) . '"' . $eol : '';
        foreach ($data as $line) {
            $csv .= '"' . implode('"' . $sep . '"', $line) . '"' . $eol;
        }
        $encoded_csv = mb_convert_encoding($csv, 'UTF-16LE', 'UTF-8');
        header('Content-Description: File Transfer');
        header('Content-Type: application/vnd.ms-excel');
        header('Content-Disposition: attachment; filename="' . $filename . '.csv"');
        header('Content-Transfer-Encoding: binary');
        header('Expires: 0');
        header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
        header('Pragma: public');
        header('Content-Length: ' . strlen($encoded_csv));
        echo chr(255) . chr(254) . $encoded_csv;
        exit;
    }