Issue [#2113513]: Users may now exclude the DTSTAMP field from their feeds.

Some ical feed readers will erroneously take the DTSTAMP field into
consideration when comparing a new download to a previous one, and end up
treating all events as having been updated, because their DTSTAMP field is
different. This new option lets you get around those buggy readers.

I also added the CREATED field, which was embarassingly missing until now.

includes/date_ical_plugin_row_ical_entity.inc

@@ -331,14 +331,19 @@ class date_ical_plugin_row_ical_entity extends views_plugin_row {
       $this->entities[$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.
+    // According to the iCal standard, CREATED and 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.
+    if (isset($entity->created)) {
+      $event['created'] = new DateObject($entity->created, new DateTimeZone('UTC'));
+    }
+    // Pull the 'changed' date from the entity (if available), so that
+    // subscription clients can tell if the event has been updated.
     if (isset($entity->changed)) {
       $event['last-modified'] = new DateObject($entity->changed, new DateTimeZone('UTC'));
     }
     else if (isset($entity->created)) {
-      // If the changed date isn't set, but the created date is, use that instead.
+      // If changed is unset, but created is, use that for last-modified.
       $event['last-modified'] = new DateObject($entity->created, new DateTimeZone('UTC'));
     }
     

includes/date_ical_plugin_row_ical_fields.inc

@@ -104,6 +104,7 @@ class date_ical_plugin_row_ical_fields extends views_plugin_row {
     // because this function must be compatible with views_plugin_row::render().
     $args = func_get_args();
     $row_index = $args[1];
+    $date_field_name = $this->options['date_field'];
     
     // Fetch the event's date information.
     try {
@@ -123,33 +124,38 @@ class date_ical_plugin_row_ical_fields extends views_plugin_row {
     // Create the event by starting with the date array from this row.
     $event = $date;
     
-    // Add the LAST-MODIFIED and URL components based on the original entity.
+    // Add the CREATED, LAST-MODIFIED, and URL components based on the entity.
+    // According to the iCal standard, CREATED and 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.
     $entity = $row->_field_data[$this->view->base_field]['entity'];
     $entity_type = $row->_field_data[$this->view->base_field]['entity_type'];
+    if (isset($entity->created)) {
+      $event['created'] = new DateObject($entity->created, new DateTimeZone('UTC'));
+    }
     if (isset($entity->changed)) {
       $event['last-modified'] = new DateObject($entity->changed, new DateTimeZone('UTC'));
     }
     else if (isset($entity->created)) {
-      // If the changed date isn't set, but the created date is, use that instead.
+      // If changed is unset, but created is, use that for last-modified.
       $event['last-modified'] = new DateObject($entity->created, new DateTimeZone('UTC'));
     }
-    
     $uri = entity_uri($entity_type, $entity);
     $uri['options']['absolute'] = TRUE;
     $event['url'] = url($uri['path'], $uri['options']);
     
     // Generate a unique ID for this event by emulating the way the Date module
     // creates a Date ID.
-    if (isset($row->{"field_data_{$this->options['date_field']}_delta"})) {
-      $date_field_delta = $row->{"field_data_{$this->options['date_field']}_delta"};
+    if (isset($row->{"field_data_{$date_field_name}_delta"})) {
+      $date_field_delta = $row->{"field_data_{$date_field_name}_delta"};
     }
     else {
-      // I'm not sure why the "field_data_<field_name>_delta" field is part of
+      // I'm not sure why the "field_data_{field_name}_delta" field is part of
       // the $row, so it's possible that it will sometimes be missing. If it
       // is, make an educated guess about the delta by comparing this row's
       // start date to each of the entity's dates.
       $date_field_delta = 0;
-      foreach ($entity->{$this->options['date_field']}['und'] as $ndx => $date_array) {
+      foreach ($entity->{$date_field_name}['und'] as $ndx => $date_array) {
         if ($date['start']->originalTime == $date_array['value']) {
           $date_field_delta = $ndx;
           break;
@@ -157,7 +163,6 @@ class date_ical_plugin_row_ical_fields extends views_plugin_row {
       }
     }
     $entity_id = $row->{$this->view->base_field};
-    $date_field_name = $this->options['date_field'];
     $domain = check_plain($_SERVER['SERVER_NAME']);
     $event['uid'] = "calendar.$entity_id.$date_field_name.$date_field_delta@$domain";
     

includes/date_ical_plugin_style_ical_feed.inc

@@ -10,7 +10,7 @@
  */
 class date_ical_plugin_style_ical_feed extends views_plugin_style {
   
-  function _get_option($option_name) {
+  protected function _get_option($option_name) {
     return isset($this->options[$option_name]) ? $this->options[$option_name] : '';
   }
   
@@ -51,8 +51,9 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
   function option_definition() {
     $options = parent::option_definition();
     $options['cal_name'] = array('default' => array());
-    $options['no_calname'] = array('default' => array());
-    $options['disable_webcal'] = array('default' => array());
+    $options['no_calname'] = array('default' => FALSE, 'bool' => TRUE);
+    $options['disable_webcal'] = array('default' => FALSE, 'bool' => TRUE);
+    $options['exclude_dtstamp'] = array('default' => FALSE, 'bool' => TRUE);
     return $options;
   }
   
@@ -82,6 +83,15 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
         clients to easily subscribe to the feed. If you want your users to instead download this iCal
         feed as a file, activate this option."),
     );
+    $form['exclude_dtstamp'] = array(
+      '#type' => 'checkbox',
+      '#title' => t('Exclude DTSTAMP'),
+      '#default_value' => $this->_get_option('exclude_dtstamp'),
+      '#description' => t("By default, the feed will set each event's DTSTAMP property to the time at which the feed got downloaded.
+        Some feed readers will (incorrectly) look at the DTSTAMP value when they compare different downloads of the same feed, and
+        conclcude that the event has been updated (even though it hasn't actually changed). Enable this option to exclude the DTSTAMP
+        field from your feeds, so that these buggy feed readers won't mark every event as updated every time they check."),
+    );
   }
   
   function render() {
@@ -309,6 +319,18 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
             $lm['timezone']
           );
         }
+        if (!empty($event['created'])) {
+          $created = $event['created']->toArray();
+          $vevent->setCreated(
+            $created['year'],
+            $created['month'],
+            $created['day'],
+            $created['hour'],
+            $created['minute'],
+            $created['second'],
+            $created['timezone']
+          );
+        }
         
         // Allow other modules to alter the VEVENT object.
         drupal_alter('date_ical_feed_ical_vevent_render', $vevent, $this->view, $event);
@@ -331,6 +353,22 @@ class date_ical_plugin_style_ical_feed extends views_plugin_style {
       // might be going too far.
       $output = str_replace('\,', ',', $output);
       $output = str_replace('\;', ';', $output);
+      
+      // In order to respect the Exclude DTSTAMP option, we unfortunately have
+      // to parse out the DTSTAMP properties after they get rendered. Simply
+      // using deleteProperty('DTSTAMP') doesn't work, because iCalcreator
+      // considers the DTSTAMP to be essential, and will re-create it when
+      // createCalendar() is called.
+      if ($this->_get_option('exclude_dtstamp')) {
+        $filtered_lines = array();
+        foreach (explode("\r\n", $output) as $line) {
+          if (strpos($line, 'DTSTAMP') === 0) {
+            continue;
+          }
+          $filtered_lines[] = $line;
+        }
+        $output = implode("\r\n", $filtered_lines);
+      }
     }
     
     // These steps shouldn't be run when doing a Preview on the View config page.