Override views_handler_field_date to fix DST problems

Currently when using any field handled by Views' views_handler_field_date, any time of future dates in winter time are shown with one hour ahead when displayed during summer time (and vice versa) because views_handler_field_date uses Drupal's format_date() function, which uses offsets instead of timezones.

I suggest that the date_api module, which introduces timezones for Drupal 6, replaces views_handler_field_date by its own field handler which uses the timezone-aware functions of date_api (date_make_date() and date_format_date()).

In date_api.views.inc:

/**
 * Implementation of hook_views_handlers() to register all of the basic handlers
 * views uses.
 */
function date_api_views_handlers() {
  return array(
    'info' => array(
      'path' => drupal_get_path('module', 'date_api') .'/includes',
      ),
    'handlers' => array(
      'date_api_argument_handler' => array(
        'parent' => 'views_handler_argument_date',
      ),
      'date_api_filter_handler' => array(
        'parent' => 'views_handler_filter_numeric',
      ),
      'date_api_field_handler' => array(
        'parent' => 'views_handler_field_date',
      ),
    ),
  );
}

/**
 * Replace handler 'views_handler_field_date' by 'date_api_field_handler' 
 */
function date_api_views_data_alter(&$data) {
  foreach ($data as $table => $config) {
    foreach ($config as $item => $item_config) {
      if (isset($item_config['field']) && $item_config['field']['handler'] == 'views_handler_field_date') {
        $data[$table][$item]['field']['handler'] = 'date_api_field_handler';
      }
    }
  }
}

In the new date_api_field_handler.inc:

<?php

/**
 * Replacement for views_handler_field_date, which takes into account real timezones instead of offsets,
 * which causes time of days in daylight saving time to be displayed wrongly on days in non-daylight saving time,
 * and vice versa.
 */
class date_api_field_handler extends views_handler_field_date {

  function render($values) {
    $value = $values->{$this->field_alias};
    $format = $this->options['date_format'];
    if (in_array($format, array('custom', 'raw time ago', 'time ago', 'raw time span', 'time span'))) {
      $custom_format = $this->options['custom_date_format'];
    }

    if (!$value) {
      return theme('views_nodate');
    }
    else {
      $time_diff = time() - $value; // will be positive for a datetime in the past (ago), and negative for a datetime in the future (hence)
      switch ($format) {
        case 'raw time ago':
          return format_interval($time_diff, is_numeric($custom_format) ? $custom_format : 2);
        case 'time ago':
          return t('%time ago', array('%time' => format_interval($time_diff, is_numeric($custom_format) ? $custom_format : 2)));
        case 'raw time span':
          return ($time_diff < 0 ? '-' : '') . format_interval(abs($time_diff), is_numeric($custom_format) ? $custom_format : 2);
        case 'time span':
          return t(($time_diff < 0 ? '%time hence' : '%time ago'), array('%time' => format_interval(abs($time_diff), is_numeric($custom_format) ? $custom_format : 2)));
        case 'custom':
          $date = date_make_date($value, date_default_timezone(), DATE_UNIX);
          return date_format_date($date, $format, $custom_format);
        default:
          $date = date_make_date($value, date_default_timezone(), DATE_UNIX);
          return date_format_date($date, $format);
      }
    }
  }
}