[PHP] phpで日本の祝日や振替休日を出力する。

get_holidays_this_month.php

<?php
function get_holidays_this_month($year, $month){
    // 月初日
    $first_day = mktime(0, 0, 0, intval($month), 1, intval($year));

    // 月末日
    $last_day = strtotime('-1 day', mktime(0, 0, 0, intval($month) + 1, 1, intval($year)));
 
    $holidays_url = sprintf(
            'http://www.google.com/calendar/feeds/%s/public/full-noattendees?start-min=%s&amp;start-max=%s&amp;max-results=%d&amp;alt=json' ,
            'japanese__ja@holiday.calendar.google.com' ,
            date('Y-m-d', $first_day) ,  // 取得開始日
            date('Y-m-d', $last_day) ,   // 取得終了日
            31            // 最大取得数
            );
    if ( $results = file_get_contents($holidays_url) ) {
            $results = json_decode($results, true);
            $holidays = array();
            foreach ($results['feed']['entry'] as $val ) {
                    $date  = $val['gd$when'][0]['startTime'];
                    $week = date('w',strtotime($date));
                    $title = $val['title']['$t'];
                    $holidays[$date] = $title;
 
                    if( $week == 0) {
                        $nextday = date('Y-m-d',strtotime('+1 day', strtotime($date)));
                        $holidays[$nextday] = '振替休日';
                    }
 
                    $before_yesterday = date('Y-m-d',strtotime('-2 day', strtotime($date)));
 
                    if(isset($holidays[$before_yesterday])){
                        $yesterday = date('Y-m-d',strtotime('-1 day', strtotime($date)));
                        $holidays[$yesterday] = '国民の休日';
                    }
 
            }
            ksort($holidays);
    }
    return $holidays;
}