-/**
- * Checks and cleans a URL.
- *
- * A number of characters are removed from the URL. If the URL is for displaying
- * (the default behaviour) amperstands are also replaced. The 'esc_url' filter
- * is applied to the returned cleaned URL.
- *
- * @since 1.2.0
- * @uses wp_kses_bad_protocol() To only permit protocols in the URL set
- * via $protocols or the common ones set in the function.
- *
- * @param string $url The URL to be cleaned.
- * @param array $protocols Optional. An array of acceptable protocols.
- * Defaults to 'http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet' if not set.
- * @param string $context Optional. How the URL will be used. Default is 'display'.
- * @return string The cleaned $url after the 'cleaned_url' filter is applied.
- */
-function clean_url( $url, $protocols = null, $context = 'display' ) {
- $original_url = $url;
-
- if ('' == $url) return $url;
- $url = preg_replace('|[^a-z0-9-~+_.?#=!&;,/:%@$\|*\'()\\x80-\\xff]|i', '', $url);
- $strip = array('%0d', '%0a', '%0D', '%0A');
- $url = _deep_replace($strip, $url);
- $url = str_replace(';//', '://', $url);
- /* If the URL doesn't appear to contain a scheme, we
- * presume it needs http:// appended (unless a relative
- * link starting with / or a php file).
- */
- if ( strpos($url, ':') === false &&
- substr( $url, 0, 1 ) != '/' && substr( $url, 0, 1 ) != '#' && !preg_match('/^[a-z0-9-]+?\.php/i', $url) )
- $url = 'http://' . $url;
-
- // Replace ampersands and single quotes only when displaying.
- if ( 'display' == $context ) {
- $url = preg_replace('/&([^#])(?![a-z]{2,8};)/', '&$1', $url);
- $url = str_replace( "'", ''', $url );
- }
-
- if ( !is_array($protocols) )
- $protocols = array('http', 'https', 'ftp', 'ftps', 'mailto', 'news', 'irc', 'gopher', 'nntp', 'feed', 'telnet');
- if ( wp_kses_bad_protocol( $url, $protocols ) != $url )
- return '';
-
- return apply_filters('clean_url', $url, $original_url, $context);
-}
-