CRM/Utils/ICalendar.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | Copyright CiviCRM LLC. All rights reserved.                        |
   5  |                                                                    |
   6  | This work is published under the GNU AGPLv3 license with some      |
   7  | permitted exceptions and without any warranty. For full license    |
   8  | and copyright information, see https://civicrm.org/licensing       |
   9  +--------------------------------------------------------------------+
  10  */
  11
  12 /**
  13  *
  14  * @package CRM
  15  * @copyright CiviCRM LLC https://civicrm.org/licensing
  16  */
  17
  18 /**
  19  * @file
  20  * API for event export in iCalendar format
  21  * as outlined in Internet Calendaring and
  22  * Scheduling Core Object Specification
  23  */
  24 class CRM_Utils_ICalendar {
  25
  26   /**
  27    * Escape text elements for safe ICalendar use.
  28    *
  29    * @param string $text
  30    *   Text to escape.
  31    * @param bool $keep_html
  32    *   Flag to retain HTML formatting
  33    * @param int $position
  34    *   Column number of the start of the string in the ICal output - used to
  35    *   determine allowable length of the first line
  36    *
  37    * @return string
  38    */
  39   public static function formatText($text, $keep_html = FALSE, int $position = 0) {
  40     if (!$keep_html) {
  41       $text = preg_replace(
  42         '{ <a [^>]+ \\b href=(?: "( [^"]+ )" | \'( [^\']+ )\' ) [^>]* > ( [^<]* ) </a> }xi',
  43         '$3 ($1$2)',
  44         $text
  45       );
  46       $text = preg_replace(
  47         '{ < / [^>]+ > \s* }',
  48         "\$0 ",
  49         $text
  50       );
  51       $text = preg_replace(
  52         '{ <(br|/tr|/div|/h[1-6]) (\s [^>]*)? > (\s* \n)? }xi',
  53         "\$0\n",
  54         $text
  55       );
  56       $text = preg_replace(
  57         '{ </p> (\s* \n)? }xi',
  58         "\$0\n\n",
  59         $text
  60       );
  61       $text = strip_tags($text);
  62       $text = html_entity_decode($text, ENT_QUOTES | ENT_HTML401, 'UTF-8');
  63     }
  64
  65     $text = str_replace("\\", "\\\\", $text);
  66     $text = str_replace(',', '\,', $text);
  67     $text = str_replace(';', '\;', $text);
  68     $text = str_replace(["\r\n", "\n", "\r"], "\\n ", $text);
  69
  70     // Remove this check after PHP 7.4 becomes a minimum requirement
  71     $str_split = function_exists('mb_str_split') ? 'mb_str_split' : 'str_split';
  72
  73     if ($keep_html) {
  74       $text = '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"><html><body>' . $text . '</body></html>';
  75     }
  76     $prefix = '';
  77     if ($position) {
  78       $prefixlen = max(50 - $position, 0);
  79       $prefix = mb_substr($text, 0, $prefixlen) . "\n ";
  80       $text = mb_substr($text, $prefixlen);
  81     }
  82     $text = $prefix . implode("\n ", $str_split($text, 50));
  83     return $text;
  84   }
  85
  86   /**
  87    * Restore iCal formatted text to normal.
  88    *
  89    * @param string $text
  90    *   Text to unescape.
  91    *
  92    * @return string
  93    */
  94   public static function unformatText($text) {
  95     $text = str_replace("\n ", "", $text);
  96     $text = str_replace('\n ', "\n", $text);
  97     $text = str_replace('\;', ';', $text);
  98     $text = str_replace('\,', ',', $text);
  99     $text = str_replace("\\\\", "\\", $text);
 100     $text = str_replace("DQUOTE", "\"", $text);
 101     return $text;
 102   }
 103
 104   /**
 105    * Escape date elements for safe ICalendar use.
 106    *
 107    * @param string $date
 108    *   Date to escape.
 109    *
 110    * @param bool $gdata
 111    *
 112    * @return string
 113    *   Escaped date
 114    */
 115   public static function formatDate($date, $gdata = FALSE) {
 116
 117     if ($gdata) {
 118       return date("Y-m-d\TH:i:s.000",
 119         strtotime($date)
 120       );
 121     }
 122     else {
 123       return date("Ymd\THis",
 124         strtotime($date)
 125       );
 126     }
 127   }
 128
 129   /**
 130    * Send the ICalendar to the browser with the specified content type
 131    * - 'text/calendar' : used for iCal formatted feed
 132    * - 'text/xml'      : used for gData or rss formatted feeds
 133    *
 134    *
 135    * @param string $calendar
 136    *   The calendar data to be published.
 137    * @param string $content_type
 138    * @param string $charset
 139    *   The character set to use, defaults to 'us-ascii'.
 140    * @param string $fileName
 141    *   The file name (for downloads).
 142    * @param string $disposition
 143    *   How the file should be sent ('attachment' for downloads).
 144    */
 145   public static function send($calendar, $content_type = 'text/calendar', $charset = 'us-ascii', $fileName = NULL, $disposition = NULL) {
 146     $config = CRM_Core_Config::singleton();
 147     $lang = $config->lcMessages;
 148     CRM_Utils_System::setHttpHeader("Content-Language", $lang);
 149     CRM_Utils_System::setHttpHeader("Content-Type", "$content_type; charset=$charset");
 150
 151     if ($fileName) {
 152       CRM_Utils_System::setHttpHeader('Content-Length', strlen($calendar));
 153       CRM_Utils_System::setHttpHeader("Content-Disposition", "$disposition; filename=\"$fileName\"");
 154       CRM_Utils_System::setHttpHeader("Pragma", "no-cache");
 155       CRM_Utils_System::setHttpHeader("Expires", "0");
 156       CRM_Utils_System::setHttpHeader("Cache-Control", "no-cache, must-revalidate");
 157     }
 158
 159     echo $calendar;
 160   }
 161
 162   /**
 163    * @param array $timezones - Timezone strings
 164    * @param $date_min
 165    * @param $date_max
 166    *
 167    * @return array
 168    */
 169   public static function generate_timezones(array $timezones, $date_min, $date_max) {
 170     if (empty($timezones)) {
 171       return [];
 172     }
 173
 174     $tz_items = [];
 175
 176     foreach ($timezones as $tzstr) {
 177       $timezone = new DateTimeZone($tzstr);
 178
 179       $transitions = $timezone->getTransitions($date_min, $date_max);
 180
 181       if (count($transitions) === 1) {
 182         $transitions[] = array_values($transitions)[0];
 183       }
 184
 185       $item = [
 186         'id' => $timezone->getName(),
 187         'transitions' => [],
 188       ];
 189
 190       $last_transition = array_shift($transitions);
 191
 192       foreach ($transitions as $transition) {
 193         $item['transitions'][] = [
 194           'type' => $transition['isdst'] ? 'DAYLIGHT' : 'STANDARD',
 195           'offset_from' => self::format_tz_offset($last_transition['offset']),
 196           'offset_to' => self::format_tz_offset($transition['offset']),
 197           'abbr' => $transition['abbr'],
 198           'dtstart' => date_create($transition['time'], $timezone)->format("Ymd\THis"),
 199         ];
 200
 201         $last_transition = $transition;
 202       }
 203
 204       $tz_items[] = $item;
 205     }
 206
 207     return $tz_items;
 208   }
 209
 210   protected static function format_tz_offset($offset) {
 211     $offset /= 60;
 212     $hours = intval($offset / 60);
 213     $minutes = abs(intval($offset % 60));
 214
 215     return sprintf('%+03d%02d', $hours, $minutes);
 216   }
 217
 218 }