get 8 day data from google calader (Use this URL to access this calendar from a web browser.)

php-get-calendar-public.php

<?php

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);


$input = 'https://calendar.google.com/calendar/embed?src=a56ac6da1d0184b389b3f590ba25b686b1bc6580f5666b0c6ae63259b31cbb1b%40group.calendar.google.com&ctz=Asia%2FHo_Chi_Minh';

$resl = builLink($input);
var_dump($resl);

function builLink($calendarId){
	$id = getIdFromPublic($calendarId);

	$arrDefault = getArrayDefault();
	$data = array_merge($arrDefault, []);
	$arrCondition = getArrayCondition();
	$data = array_merge($data, $arrCondition);
	$data['key'] = getkey($calendarId);
	$rs = getRequestLink($id, $data);
	return $rs;
}
function getRequestLink($id = '', $more = []){
	$link = 'https://clients6.google.com/calendar/v3/calendars/'.$id.'@group.calendar.google.com/events?calendarId='.$id.'%40group.calendar.google.com';
	//$strmore = implode('&',$more);
	$strmore = http_build_query($more);
	return $link.'&'.$strmore;
}

function getkey($url){
	$html = file_get_contents($url);
	// Define the regular expression pattern to match the developerKey
	$pattern = '/"developerKey":"(.*?)"/';
	// Use preg_match to find the developerKey in the HTML content
	if (preg_match($pattern, $html, $matches)) {
		$developerKey = $matches[1];
		return $developerKey;
	} else {
		return '';
	}
}

//https: //calendar.google.com/calendar/embed?src=a56ac6da1d0184b389b3f590ba25b686b1bc6580f5666b0c6ae63259b31cbb1b%40group.calendar.google.com&ctz=Asia%2FHo_Chi_Minh
function getIdFromPublic($input){
	$data = parse_url($input);
	parse_str($data['query'], $par);
	$id = '';
	if(!empty($par['src'])){
		$array = explode('@', $par['src']);
		if(isset($array[0])){
			$id = $array[0];
		}
	}
	return $id;
}

function getArrayLink($link = ''){
	$data = parse_url($link);
	parse_str($data['query'], $par);
	return $par;
}
function getArrayCondition(){
	$now = new DateTime();
	$lastDay = $now->modify('-1 day')->format('Y-m-d\TH:i:s.u\Z');
	$next7Day = $now->modify('+7 day')->format('Y-m-d\TH:i:s.u\Z');
	$data = [
		'timeMin' => $lastDay,
		'timeMax' => $next7Day,
		//'timeMin' => '2024-02-25T00:00:00+07:00',
		//'timeMax' => '2024-04-07T00:00:00+07:00',
		'$unique' => 'gc456',
	];
	return $data;
}

function getArrayDefault(){
	$data = [
		'singleEvents' => 'true',
		'eventTypes' => 'default',
		//'eventTypes' => 'outOfOffice',//focusTime
		'timeZone' => 'Asia/Ho_Chi_Minh',
		//'maxAttendees' => '1',
		'maxResults' => '250',
		'sanitizeHtml' => 'true',
		//'key' => 'AIzaSyBNlYH01_9Hc5S1J9vuFmu2nUqBZJNAXxs',
	];
	return $data;
}