caldav2ics.php

#!/usr/bin/env php
<?php
	
	use Symfony\Component\Yaml\Yaml;
	use Symfony\Component\DomCrawler\Crawler;

	// Standalone CalDav2ics (e.g. for cron job...)
	// stores Logfile and Calendar File in same Directory as script
	// can fetch/process multiple calendars at once, just put these as a json encoded array in $CalendarsFile, a sample File is included here for convenience
	// from V 1.1.0, this program includes and uses Symfony\Component\Yaml class, so it can read native yaml Files even when used on a server that has php-yaml not installed.
	// so, no more need to use 'fake' yaml files that contain json data :-)

	//	Config goes here:
	$verbose = true;
	$LogEnabled = true;
	$RequestTimeout = '20';	// default Timeout for curl Request
	$LogFile = pathinfo(__FILE__, PATHINFO_DIRNAME)."/logfile.txt";
	$CalendarsFile = pathinfo(__FILE__, PATHINFO_DIRNAME)."/caldav2ics.yaml";	// config file name, yaml Format for security reasons !
	//	feel free to use your own $CalendarsFile PATH - just be sure it is correct :-)
	//	alternatively, you can provide the Calendars File Name via commandline, Argument 1, see code below. Same goes for $ICSpath (optional Argument 2)
	$ICSpath = pathinfo(__FILE__, PATHINFO_DIRNAME);	// default
	// here you can still use the old, hardcoded parameter definition, this must, however, be in array notation, like follows (just comment out the 'die..' in the line above):
	$Config = array (
		"calendars" => array (
			array (
				"Name"=>"TestCalendar",
				"Url"=>"https://yourcaldavserver.net/remote.php/dav/calendars/myuser/pubcal",
				"User"=>"myuser",
				"Pass"=>"my#secret!Password",
			),
		)
	  );
	//	end Config
	
	require_once './vendor/autoload.php';

	if ($argc > 1)
		$CalendarsFile = $argv[1];
	if ($argc > 2)
		$ICSpath = $argv[2];	// currently unused, just ignore :-)
	if ( file_exists($CalendarsFile) ) {
		$Config = Yaml::parseFile($CalendarsFile);	// now, this is a real yaml file ;-)
		if ($verbose)	var_dump($Config);
		if (is_array($Config['calendars']))	{
			$calendars = $Config['calendars'];
			//	var_dump($calendars);
			foreach($calendars as $calendar)	{
				//	var_dump($calendar);
			}
		}	else {
			die("invalid Calendar data, aborted!");
		}
		//	exit;
	}	else	{	
		echo("Calendars File not found, using default Config data !");
	}
	
	// commonly used ics Properties, see https://en.wikipedia.org/wiki/ICalendar
	$Properties = ["DTSTAMP","URL","URL;VALUE=URI","CREATED","UID","LAST-MODIFIED","SUMMARY","LOCATION","DTSTAMP","DTSTART","DTSTART;VALUE=DATE","DTEND","DTEND;VALUE=DATE","TRANSP","DESCRIPTION","UID","CLASS","STATUS","SEQUENCE","RRULE","RDATE","EXDATE","BEGIN","END","TRIGGER","ACTION","CATEGORIES","GEO","ATTENDEE","ROLE","EMAIL","CN"];
	
	foreach ($calendars as $calendar) {
		if ($verbose)	var_dump($calendar);
		$cal = $calendar;	//	(array) $calendars;
		$name = $cal["Name"];
		$calendar_url = $cal['Url'];
		$calendar_user = $cal['User'];
		$calendar_password = $cal['Pass'];
		
		$ICalFile = $ICSpath."/".$name.".ics";	// ical file name
		if ($verbose) {
			echo "\n";
			echo "$name\n";
			echo "$calendar_url\n";
			echo "$calendar_user\n";
			echo "$calendar_password\n";
			echo "$ICalFile\n";
		}
		//	continue;	//	NOT	break;
		$fmdelay = 60;	// seconds
		
		if ($LogEnabled)	{
			$loghandle = fopen($LogFile, 'w') or die('Cannot open file:  '.$LogFile);
		}
		if (empty($calendar_url) || empty($calendar_user) || empty($calendar_password))	{
			if (!$LogEnabled) {
				$loghandle = fopen($LogFile, 'w') or die('Cannot open file:  '.$LogFile);
			}
			fwrite($loghandle, "Invalid Settings !\n");
			fwrite($loghandle, "Calendar URL: ".$calendar_url." must be specified\n");
			fwrite($loghandle, "Username: ".$calendar_user." must be specified\n");
			fwrite($loghandle, "Password: ".$calendar_password." must be specified\n");
			fclose($loghandle);
			return;
		}
		
		if (filter_var($calendar_url, FILTER_VALIDATE_URL) === false) {
			print_r("Invalid Calendar URL: ", $calendar_url);
			if (!$LogEnabled) {
				$loghandle = fopen($LogFile, 'w') or die('Cannot open file:  '.$LogFile);
				fwrite($loghandle, "Invalid Calendar URL: ", $calendar_url);
				fclose($loghandle);
			}
			return;
		}

		if ($LogEnabled)	{
			print_r($calendar_url);
			fwrite($loghandle, $calendar_url."\n");
			fwrite($loghandle, $calendar_user."\n");
			fwrite($loghandle, $calendar_password."\n");
			fwrite($loghandle, "Delay:".$fmdelay."\n");
			fwrite($loghandle, "EnableLog:".$LogEnabled."\n");
		}	
		// Simple caching system, feel free to change the delay
		if (file_exists($ICalFile)) {
			$last_update = filemtime($ICalFile);
		} else {
			$last_update = 0;
		}
		if ($last_update + $fmdelay < time()) {	

			// Get events
			$headers = array(
				'Content-Type: application/xml; charset=utf-8',
				'Depth: 1',
				'Prefer: return-minimal'
			);
			
			// see https://uname.pingveno.net/blog/index.php/post/2016/07/30/Sample-public-calendar-for-ownCloud-using-ICS-parser
			// Prepare request body, MANDATORY !
			$doc  = new DOMDocument('1.0', 'utf-8');
			$doc->formatOutput = true;

			$query = $doc->createElement('c:calendar-query');
			$query->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:c', 'urn:ietf:params:xml:ns:caldav');
			$query->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:d', 'DAV:');

			$prop = $doc->createElement('d:prop');
			$prop->appendChild($doc->createElement('d:getetag'));
			$prop->appendChild($doc->createElement('c:calendar-data'));
			$query->appendChild($prop);

			$prop = $doc->createElement('c:filter');
			$filter = $doc->createElement('c:comp-filter');
			$filter->setAttribute('name', 'VCALENDAR');
			$prop->appendChild($filter);
			$query->appendChild($prop);

			$doc->appendChild($query);
			$body = $doc->saveXML();
			
			// Debugging purpose
			if ($LogEnabled) { 
				echo htmlspecialchars($body);
				fwrite($loghandle, htmlspecialchars($body));
			}

			// Prepare cURL request
			
			$ch = curl_init();
			curl_setopt($ch, CURLOPT_URL, $calendar_url);
			curl_setopt($ch, CURLOPT_USERPWD, $calendar_user . ':' . $calendar_password);
			curl_setopt($ch, CURLOPT_VERBOSE, 1);
			curl_setopt($ch, CURLOPT_TIMEOUT, $RequestTimeout);	// DONE: set Timeout, see https://thisinterestsme.com/php-setting-curl-timeout/
			curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
			curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
			curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
			curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
			curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
			curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'REPORT');
			curl_setopt($ch, CURLOPT_POSTFIELDS, $body);

			$response = curl_exec($ch);
			if (curl_error($ch)) {
				if ($LogEnabled) { 
					echo curl_error($ch); 
					fwrite($loghandle, curl_error($ch));
					fclose($loghandle);
				}
				return;
			}
			curl_close($ch);

			// Debugging purpose
			if ($LogEnabled) { 
				echo htmlspecialchars($response);
				fwrite($loghandle, htmlspecialchars($response));
			}

			// Get the useful part of the response
			/*	skip any xml conversion/parsing
			*/

			// Parse events
			$calendar_events = array();
			$handle = fopen($ICalFile, 'w') or die('Cannot open file:  '.$ICalFile);
			
			// create valid ICS File with only ONE Vcalendar !
			// write VCALENDAR header
			fwrite($handle, 'BEGIN:VCALENDAR'."\r\n");
			fwrite($handle, 'VERSION:2.0'."\r\n");
			fwrite($handle, 'PRODID:-//hoernerfranzracing/caldav2ics.php'."\r\n");
			// find and write TIMEZONE data, new feature, 27.12.19
			$skip = true;
			$wroteTZ = false;
			$lines = explode("\n", $response);
			foreach ($lines as $line)   {
				$line = trim($line);
				if ( !$wroteTZ )	{
					if (startswith($line,'BEGIN:VTIMEZONE'))	{
						$skip = false;
					}
					if ( !$skip )	{
						fwrite($handle, $line."\r\n"); // write everything between 'BEGIN:VTIMEZONE' and 'END:VTIMEZONE'
						// echo $line."\n";
					}
					if (startswith($line,'END:VTIMEZONE'))	{
						$skip = true;
						$wroteTZ = true;    // only write VTIMEZONE entry once
					}
				}
			}
			// parse $response, do NOT write VCALENDAR header for each one, just the event data
			foreach ($lines as $line) {
				$line = trim($line,"\n\r\t\v\x00");	// mod. 17.07.23 WJ, see https://wordpress.org/support/topic/converted-openxchange-calendar-subscibe-to-google-didnt-work/
				if (strlen($line) > 0) {	// mod. 17.07.23 WJ
					if (strstr($line,'BEGIN:VCALENDAR'))	{	// first occurrence might not be at line start
						$skip = true;
					}
					if (startswith($line,'PRODID:'))	{
						$skip = true;
					}
					if (strstr($line,'VERSION:'))	{
						$skip = true;	// VERSION can appear in different places
					}
					if (startswith($line,'CALSCALE:'))	{
						$skip = true;
					}
					if (startswith($line,'BEGIN:VEVENT'))	{
						$skip = false;
						//fwrite($handle, "\r\n");	// improves readability, but triggers warning in validator :)
					}
					if (startswith($line,'END:VCALENDAR'))	{
						$skip = true;
					}
					// more validations 20.09.24
					//if (!str_contains($line, ':')) {	// skip all lines that do not contain ':' (Keyword)
					if (!strpos($line, ':')) {	// TODO: better join lines to previous one :-)
						$skip = true;
					}	else {
						$parts = explode(":",$line);
						$keyword = $parts[0];
						if (in_array($keyword, $Properties))  {
							$skip = false;
							if (startswith($line,'END:VCALENDAR'))	{
								$skip = true;
							}
						}	else	{
							if (startswith($line,'ORGANIZER;CN=')) {
								$skip = false;
							}	else	{
								$skip = true;
							}
						}
					}
					if ( !$skip )	{
						if ((startswith($line,'URL:')) || (startswith($line,'URL;VALUE=URI:'))) {	// check if 'URL:..' Line contains valid URL
							$url = str_replace("URL:", "", $line);
							$url = str_replace("URL;VALUE=URI:", "", $url);
							$url = trim($url);
							if (filter_var($url, FILTER_VALIDATE_URL) === FALSE) {
								if ($LogEnabled)	{
									fwrite($loghandle, $url.' is Not a valid URL'."\r\n");
									fwrite($loghandle, "Line: ".$line."\r\n");
								}
							}	else {
								fwrite($handle, $line."\r\n");
							}
						}	else {
							fwrite($handle, $line."\r\n");
						}
					}
				}
			}
			fwrite($handle, 'END:VCALENDAR'."\r\n");
			fclose($handle);
				if ($LogEnabled) { 
				fclose($loghandle);
			}
		}
	}

	function startswith ($string, $stringToSearchFor) {
		if (substr(trim($string),0,strlen($stringToSearchFor)) == $stringToSearchFor) {
				// the string starts with the string you're looking for
				return true;
		} else {
				// the string does NOT start with the string you're looking for
				return false;
		}
	}
?>