[Download Calendar file] Download a calendar file according to given parameters #tools

Download_ics_file.php

include('ICS.php');
date_default_timezone_set('Europe/Amsterdam');

$date = "18-06-2022";
$time = "15:30:00";
$startTime = $date . " " . $time;

if (date('I', strtotime($startTime))) {
  $timestamp = strtotime($startTime) - (60*60*2); //minus 2 hours for server time for summer time
  $startTime = date('Y-m-d H:i:s', $timestamp);
  $endTime = date('Y-m-d H:i:s', $timestamp + (60*60)); //one hour later
  //echo 'We are in DST!';
} else {
  $timestamp = strtotime($startTime) - (60*60);
  $startTime = date('Y-m-d H:i:s', $timestamp);
  $endTime = date('Y-m-d H:i:s', $timestamp + (60*60)); //one hour later
  //echo 'We are not in DST!';
}

$desc_array = ["Array with data, one item per line", "Second line text"];
$desc = implode("\\n", $desc_array);

header('Content-Type: text/calendar; charset=utf-8');
$filename = "new_ics_file_" . time();
header("Content-Disposition: inline; filename=". $filename .".ics");

$ics = new ICS(array(
  'location' => "Korenbloemstraat 13 5409AX Odiliapeel",
  'description' => $desc,
  'dtstart' => $startTime,
  'dtend' => $endTime,
  'summary' => "The appointment title",
));

echo $ics->to_string('Europe/Amsterdam');
die;

ICS.php

//https://gist.github.com/jakebellacera/635416

/** ICS.php
 * =============================================================================
 * Use this class to create an .ics file.
 * 
 *
 * Usage
 * -----------------------------------------------------------------------------
 * Basic usage - generate ics file contents (see below for available properties):
 *   $ics = new ICS($props);
 *   $ics_file_contents = $ics->to_string();
 *
 * Setting properties after instantiation
 *   $ics = new ICS();
 *   $ics->set('summary', 'My awesome event');
 *
 * You can also set multiple properties at the same time by using an array:
 *   $ics->set(array(
 *     'dtstart' => 'now + 30 minutes',
 *     'dtend' => 'now + 1 hour'
 *   ));
 *
 * Available properties
 * -----------------------------------------------------------------------------
 * description
 *   String description of the event.
 * dtend
 *   A date/time stamp designating the end of the event. You can use either a
 *   DateTime object or a PHP datetime format string (e.g. "now + 1 hour").
 * dtstart
 *   A date/time stamp designating the start of the event. You can use either a
 *   DateTime object or a PHP datetime format string (e.g. "now + 1 hour").
 * location
 *   String address or description of the location of the event.
 * summary
 *   String short summary of the event - usually used as the title.
 * url
 *   A url to attach to the the event. Make sure to add the protocol (http://
 *   or https://).
 */

class ICS {
  const DT_FORMAT = 'Ymd\THis\Z';

  protected $properties = array();
  private $available_properties = array(
    'description',
    'dtend',
    'dtstart',
    'location',
    'summary',
    'url'
  );

  public function __construct($props) {
    $this->set($props);
  }

  public function set($key, $val = false) {
    if (is_array($key)) {
      foreach ($key as $k => $v) {
        $this->set($k, $v);
      }
    } else {
      if (in_array($key, $this->available_properties)) {
        $this->properties[$key] = $this->sanitize_val($val, $key);
      }
    }
  }

  public function to_string($timezone) {
    $rows = $this->build_props($timezone);
    return implode("\r\n", $rows);
  }

  private function build_props($timezone) {
    // Build ICS properties - add header
    $ics_props = array(
      'BEGIN:VCALENDAR',
      'VERSION:2.0',
      'PRODID:-//hacksw/handcal//NONSGML v1.0//EN',
      'CALSCALE:GREGORIAN',
      'X-WR-TIMEZONE:' . $timezone,
      'BEGIN:VEVENT'
    );

    // Build ICS properties - add header
    $props = array();
    foreach($this->properties as $k => $v) {
      $props[strtoupper($k . ($k === 'url' ? ';VALUE=URI' : ''))] = $v;
    }

    // Set some default values
    $props['DTSTAMP'] = $this->format_timestamp('now');
    $props['UID'] = uniqid();

    // Append properties
    foreach ($props as $k => $v) {
      $ics_props[] = "$k:$v";
    }

    // Build ICS properties - add footer
    $ics_props[] = 'END:VEVENT';
    $ics_props[] = 'END:VCALENDAR';

    return $ics_props;
  }

  private function sanitize_val($val, $key = false) {
    switch($key) {
      case 'dtend':
      case 'dtstamp':
      case 'dtstart':
        $val = $this->format_timestamp($val);
        break;
      default:
        $val = $this->escape_string($val);
    }

    return $val;
  }

  private function format_timestamp($timestamp) {
    $dt = new DateTime($timestamp);
    return $dt->format(self::DT_FORMAT);
  }

  private function escape_string($str) {
    return preg_replace('/([\,;])/','\\\$1', $str);
  }
}