Using WordPress ‘clean_url’ PHP filter

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The clean_url WordPress PHP filter is used to clean and escape a string for output as a URL.

Usage

add_filter('clean_url', 'your_custom_function', 10, 3);
function your_custom_function($good_protocol_url, $original_url, $_context) {
    // your custom code here
    return $good_protocol_url;
}

Parameters

  • $good_protocol_url (string) – The cleaned URL to be returned.
  • $original_url (string) – The URL prior to cleaning.
  • $_context (string) – If ‘display’, replace ampersands and single quotes only.

More information

See WordPress Developer Resources: clean_url

Examples

Remove UTM parameters

Remove UTM parameters from URLs.

add_filter('clean_url', 'remove_utm_parameters', 10, 3);
function remove_utm_parameters($good_protocol_url, $original_url, $_context) {
    $url_parts = parse_url($good_protocol_url);
    if (isset($url_parts['query'])) {
        parse_str($url_parts['query'], $query_params);
        $clean_params = array_diff_key($query_params, array_flip(['utm_source', 'utm_medium', 'utm_campaign']));
        $url_parts['query'] = http_build_query($clean_params);
        $good_protocol_url = http_build_url($url_parts);
    }
    return $good_protocol_url;
}

Add a ref parameter

Add a ‘ref’ parameter to external URLs.

add_filter('clean_url', 'add_ref_parameter', 10, 3);
function add_ref_parameter($good_protocol_url, $original_url, $_context) {
    if (strpos($good_protocol_url, home_url()) === false) {
        $good_protocol_url = add_query_arg('ref', 'your_ref_value', $good_protocol_url);
    }
    return $good_protocol_url;
}

Force HTTPS

Force all URLs to use HTTPS.

add_filter('clean_url', 'force_https', 10, 3);
function force_https($good_protocol_url, $original_url, $_context) {
    return set_url_scheme($good_protocol_url, 'https');
}

Remove www

Remove ‘www’ from URLs.

add_filter('clean_url', 'remove_www', 10, 3);
function remove_www($good_protocol_url, $original_url, $_context) {
    return preg_replace('/^www\./', '', $good_protocol_url);
}

Add a trailing slash

Add a trailing slash to URLs.

add_filter('clean_url', 'add_trailing_slash', 10, 3);
function add_trailing_slash($good_protocol_url, $original_url, $_context) {
    return trailingslashit($good_protocol_url);
}