WordPress Version: 6.1
/**
* Gets the UTC time of the most recently modified post from WP_Query.
*
* If viewing a comment feed, the time of the most recently modified
* comment will be returned.
*
* @global WP_Query $wp_query WordPress Query object.
*
* @since 5.2.0
*
* @param string $format Date format string to return the time in.
* @return string|false The time in requested format, or false on failure.
*/
function get_feed_build_date($format)
{
global $wp_query;
$datetime = false;
$max_modified_time = false;
$utc = new DateTimeZone('UTC');
if (!empty($wp_query) && $wp_query->have_posts()) {
// Extract the post modified times from the posts.
$modified_times = wp_list_pluck($wp_query->posts, 'post_modified_gmt');
// If this is a comment feed, check those objects too.
if ($wp_query->is_comment_feed() && $wp_query->comment_count) {
// Extract the comment modified times from the comments.
$comment_times = wp_list_pluck($wp_query->comments, 'comment_date_gmt');
// Add the comment times to the post times for comparison.
$modified_times = array_merge($modified_times, $comment_times);
}
// Determine the maximum modified time.
$datetime = date_create_immutable_from_format('Y-m-d H:i:s', max($modified_times), $utc);
}
if (false === $datetime) {
// Fall back to last time any post was modified or published.
$datetime = date_create_immutable_from_format('Y-m-d H:i:s', get_lastpostmodified('GMT'), $utc);
}
if (false !== $datetime) {
$max_modified_time = $datetime->format($format);
}
/**
* Filters the date the last post or comment in the query was modified.
*
* @since 5.2.0
*
* @param string|false $max_modified_time Date the last post or comment was modified in the query, in UTC.
* False on failure.
* @param string $format The date format requested in get_feed_build_date().
*/
return apply_filters('get_feed_build_date', $max_modified_time, $format);
}