Using WordPress ‘pre_get_lastpostmodified’ PHP filter

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The pre_get_lastpostmodified WordPress PHP filter allows you to modify the return value of get_lastpostmodified() before the query is executed.

Usage

add_filter('pre_get_lastpostmodified', 'your_function_name', 10, 3);

function your_function_name($lastpostmodified, $timezone, $post_type) {
    // your custom code here
    return $lastpostmodified;
}

Parameters

  • $lastpostmodified (string|false): The most recent time that a post was modified in ‘Y-m-d H:i:s’ format, or false. Returning anything other than false will short-circuit the function.
  • $timezone (string): Location to use for getting the post modified date. See get_lastpostdate() for accepted $timezone values.
  • $post_type (string): The post type to check.

More information

See WordPress Developer Resources: pre_get_lastpostmodified

Examples

Change the date format of the last modified post

Change the date format of the last modified post to ‘d/m/Y’.

add_filter('pre_get_lastpostmodified', 'change_date_format', 10, 3);

function change_date_format($lastpostmodified, $timezone, $post_type) {
    if ($lastpostmodified) {
        $lastpostmodified = date('d/m/Y', strtotime($lastpostmodified));
    }
    return $lastpostmodified;
}

Display a custom message if no posts are modified

Display a custom message if there are no modified posts.

add_filter('pre_get_lastpostmodified', 'no_modified_posts_message', 10, 3);

function no_modified_posts_message($lastpostmodified, $timezone, $post_type) {
    if (!$lastpostmodified) {
        $lastpostmodified = 'No posts have been modified.';
    }
    return $lastpostmodified;
}

Add a fixed offset to the last modified date

Add a fixed offset of 7 days to the last modified date.

add_filter('pre_get_lastpostmodified', 'add_offset_to_last_modified', 10, 3);

function add_offset_to_last_modified($lastpostmodified, $timezone, $post_type) {
    if ($lastpostmodified) {
        $lastpostmodified = date('Y-m-d H:i:s', strtotime($lastpostmodified . ' +7 days'));
    }
    return $lastpostmodified;
}

Set a minimum last modified date

Ensure the last modified date is never older than 30 days.

add_filter('pre_get_lastpostmodified', 'set_minimum_last_modified_date', 10, 3);

function set_minimum_last_modified_date($lastpostmodified, $timezone, $post_type) {
    if ($lastpostmodified) {
        $minimum_date = date('Y-m-d H:i:s', strtotime('-30 days'));
        if ($lastpostmodified < $minimum_date) {
            $lastpostmodified = $minimum_date;
        }
    }
    return $lastpostmodified;
}

Filter last modified date based on a specific post type

Display the last modified date only for ‘product’ post type.

add_filter('pre_get_lastpostmodified', 'filter_last_modified_by_post_type', 10, 3);
function filter_last_modified_by_post_type($lastpostmodified, $timezone, $post_type) {
    if ($post_type != 'product') {
        $lastpostmodified = false;
    }
    return $lastpostmodified;
}

This code will only return the last modified date if the post type is ‘product’. For other post types, the filter will return false.