Issue [#2102223]: Fix for EXDATEs in buggy calendar clients.

According to the spec, EXDATE properties can have multiple values. However, many
popular calendar client don't support that, and only accept iCal feeds which
use multiple separate EXDATE properties. That is spec-compliant, though, so I
refactored Date iCal to do that for EXDATEs and RDATEs.

includes/date_ical_plugin_row_ical_entity.inc

@@ -144,13 +144,14 @@ class date_ical_plugin_row_ical_entity extends views_plugin_row {
     global $base_url;
     $id = $row->{$this->field_alias};
     if (!is_numeric($id)) {
-      return;
+      return NULL;
     }
     
     // Load the specified entity:
     $entity = $this->entities[$id];
     if (empty($entity)) {
-      return;
+      // This can happen when an RRULE is involved.
+      return NULL;
     }
     
     $date_fields = date_views_fields($this->base_table);
@@ -170,7 +171,7 @@ class date_ical_plugin_row_ical_entity extends views_plugin_row {
     if (!isset($entity->$field_name)) {
       // This entity doesn't have the date property that the user configured
       // our view to use. We can't do anything with it
-      return;
+      return NULL;
     }
     $date_field = $entity->$field_name;
     
@@ -323,11 +324,13 @@ class date_ical_plugin_row_ical_entity extends views_plugin_row {
     // event page's URL, if the date_id isn't available.
     $event['uid'] = !empty($entity->date_id) ? $entity->date_id[0] : $event['url'];
     
-    // If we are using a repeat rule (and not just multi-day events)
-    // we remove the item from the entities.
+    // If we are using a repeat rule (and not just multi-day events) we
+    // remove the item from the entities list so that its VEVENT won't be
+    // re-created.
     if ($event['rrule']) {
       $this->entities[$id] = NULL;
     }
+    
     // Pull the 'changed' date from the entity, so that subscription clients can tell if the event has been updated.
     // According to the iCal standard, LAST-MODIFIED must be UTC. Fortunately, Drupal stores timestamps in the DB
     // as UTC, so we just need to specify that UTC be used rather than the server's local timezone.

includes/date_ical_plugin_style_ical_feed.inc

@@ -107,11 +107,15 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
     }
     unset($this->view->row_index);
     
-    // Try to load the iCalcreator library, and check if that worked.
+    // Try to load the iCalcreator library.
     $library = libraries_load('iCalcreator');
-    if (!empty($library['loaded'])) {
+    if (empty($library['loaded'])) {
+      // The iCalcreator library isn't available, so we can't output anything.
+      $output = t('Please install the iCalcreator library to enable iCal output.');
+    }
+    else {
       // Create a vcalendar object using the iCalcreator library.
-      $config = array('unique_id' => 'Drupal: Date iCal v' . DATE_ICAL_VERSION);
+      $config = array('unique_id' => 'Date iCal v' . DATE_ICAL_VERSION);
       $vcalendar = new vcalendar($config);
       $vcalendar->setMethod('PUBLISH');
       
@@ -138,7 +142,8 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
       foreach ($events as $event) {
         if (empty($event)) {
           // The row plugin returned NULL for this row, which can happen due to
-          // various error conditions. The only thing we can do is skip it.
+          // either various error conditions, or because an RRULE is involved.
+          // When this happens, just skip it.
           continue;
         }
         
@@ -161,7 +166,8 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
             $start['hour'],
             $start['minute'],
             $start['second'],
-            $timezone);
+            $timezone
+          );
         }
         
         // Add the Timezone info to the start date, for use later.
@@ -185,9 +191,9 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
               $end['hour'],
               $end['minute'],
               $end['second'],
-              $timezone);
+              $timezone
+            );
           }
-          // Keep a copy of the end date, as it's useful later.
           $end['tz'] = $event['end']->getTimezone();
         }
         $vevent->setProperty('uid', $event['uid']);
@@ -195,16 +201,17 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
         
         // Handle repeating dates from the date_repeat module.
         if (!empty($event['rrule']) && module_exists('date_repeat')) {
-          // Split the rrule into the actual rule, exceptions, and additions.
+          // Split the rrule into an RRULE and any additions and exceptions.
           module_load_include('inc', 'date_api', 'date_api_ical');
           module_load_include('inc', 'date_repeat', 'date_repeat_calc');
           list($rrule, $exceptions, $additions) = date_repeat_split_rrule($event['rrule']);
-          // Add the rrule itself. We need to massage the data a bit, since
+          
+          // Add the RRULE itself. We need to massage the data a bit, since
           // iCalcreator expects RRULEs to be in a different format than how
           // Date API gives them to us.
-          $rrule = self::convert_rrule_for_icalcreator($rrule);
-          $vevent->setRrule($rrule);
-          // Process exceptions if there are any.
+          $vevent->setRrule(self::convert_rrule_for_icalcreator($rrule));
+          
+          // Convert any exceptions to EXDATE properties.
           if (!empty($exceptions)) {
             $exdates = array();
             foreach ($exceptions as $exception) {
@@ -215,38 +222,49 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
                 'year' =>  $exception_array['year'],
                 'month' => $exception_array['month'],
                 'day' =>   $exception_array['day'],
-                // Use the time information from the start date.
+                // Use the time information from the start date, since Date
+                // doesn't store time info for EXDATEs.
                 'hour' =>   $start['hour'],
                 'min' =>    $start['minute'],
                 'second' => $start['second'],
                 'tz' =>     $start['tz']->getName(),
               );
             }
-            // Add those exclusions as 'EXDATE's.
-            $vevent->setExdate($exdates);
+            // Add each exclusion as a separate EXDATE property.
+            // The spec supports putting multiple date values into one EXDATE,
+            // but several popular calendar clients (*cough* Apple *cough*)
+            // are bugged, and do not recognize multi-value EXDATEs.
+            foreach ($exdates as $exdate) {
+              $vevent->setExdate(array($exdate));
+            }
           }
-          // Process additions if there are any.
+          
+          // Convert any additions to RDATE properties.
           if (!empty($additions)) {
-            $add_dates = array();
+            $rdates = array();
             foreach ($additions as $addition) {
               $add = date_ical_date($addition, 'UTC');
               date_timezone_set($add, $start['tz']);
               $addition_array = $add->toArray();
               
-              $add_date = array(
+              $rdate = array(
                 'year' =>  $addition_array['year'],
                 'month' => $addition_array['month'],
                 'day' =>   $addition_array['day'],
-                // Use the time information from the start date.
+                // Use the time information from the start date, since Date
+                // doesn't store time info for RDATEs.
                 'hour' =>   $start['hour'],
                 'min' =>    $start['minute'],
                 'second' => $start['second'],
                 'tz' =>     $start['tz']->getName(),
               );
-              // If there was an end date specified, use that too.
-              if (!empty($event['end'])) {
-                $add_date = array($add_date);
-                $add_date[] = array(
+              
+              // If an end date was was calculated above, use that too.
+              // iCalcreator expects RDATEs that have end dates to be
+              // specified as array($start_rdate, $end_rdate).
+              if (isset($end)) {
+                $rdate_with_end = array($rdate);
+                $rdate_with_end[] = array(
                   'year' =>  $addition_array['year'],
                   'month' => $addition_array['month'],
                   'day' =>   $addition_array['day'],
@@ -256,12 +274,18 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
                   'second' => $end['second'],
                   'tz' =>     $end['tz']->getName(),
                 );
+                $rdate = $rdate_with_end;
               }
               
-              $add_dates[] = $add_date;
+              $rdates[] = $rdate;
+            }
+            // Add each addition as a separate RDATE property.
+            // The spec supports putting multiple date values into one RDATE,
+            // but several popular calendar clients (*cough* Apple *cough*)
+            // are bugged, and do not recognize multi-value RDATEs.
+            foreach ($rdates as $rdate) {
+              $vevent->setRdate(array($rdate));
             }
-            // Add the additions as 'RDATE's.
-            $vevent->setRdate($add_dates);
           }
         }
         if (!empty($event['url'])) {
@@ -290,7 +314,7 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
         drupal_alter('date_ical_feed_ical_vevent_render', $vevent, $this->view, $event);
       }
       
-      // Now add all the timezones we just used to the calendar.
+      // Now add to the calendar all the timezones used by the events.
       foreach ($timezones as $timezone) {
         if (strtoupper($timezone) != 'UTC') {
           iCalUtilityFunctions::createTimezone($vcalendar, $timezone);
@@ -301,17 +325,13 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
       drupal_alter('date_ical_feed_ical_vcalendar_render', $vcalendar, $this->view);
       
       $output = $vcalendar->createCalendar();
-      // For some unknown reason (overzealous spec comnpliance?), iCalcreator
+      // For some unknown reason (overzealous spec compliance?), iCalcreator
       // escapes all commas and semicolons in the strings that it outputs.
       // This unescapes them, though it does it with a pretty big hammer. This
       // might be going too far.
       $output = str_replace('\,', ',', $output);
       $output = str_replace('\;', ';', $output);
     }
-    else {
-      // The iCalcreator library isn't available, so we can't output anything.
-      $output = t('Please install the iCalcreator library to enable iCal output.');
-    }
     
     // These steps shouldn't be run when doing a Preview on the View config page.
     if (empty($this->view->live_preview)) {