+
+/**
+ * A wrapper for PHP's parse_url() function that handles consistency in the return
+ * values across PHP versions.
+ *
+ * PHP 5.4.7 expanded parse_url()'s ability to handle non-absolute url's, including
+ * schemeless and relative url's with :// in the path. This function works around
+ * those limitations providing a standard output on PHP 5.2~5.4+.
+ *
+ * Secondly, across various PHP versions, schemeless URLs starting containing a ":"
+ * in the query are being handled inconsistently. This function works around those
+ * differences as well.
+ *
+ * Error suppression is used as prior to PHP 5.3.3, an E_WARNING would be generated
+ * when URL parsing failed.
+ *
+ * @since 4.4.0
+ * @since 4.7.0 The $component parameter was added for parity with PHP's parse_url().
+ *
+ * @param string $url The URL to parse.
+ * @param int $component The specific component to retrieve. Use one of the PHP
+ * predefined constants to specify which one.
+ * Defaults to -1 (= return all parts as an array).
+ * @see http://php.net/manual/en/function.parse-url.php
+ * @return mixed False on parse failure; Array of URL components on success;
+ * When a specific component has been requested: null if the component
+ * doesn't exist in the given URL; a sting or - in the case of
+ * PHP_URL_PORT - integer when it does. See parse_url()'s return values.
+ */
+function wp_parse_url( $url, $component = -1 ) {
+ $to_unset = array();
+ $url = strval( $url );
+
+ if ( '//' === substr( $url, 0, 2 ) ) {
+ $to_unset[] = 'scheme';
+ $url = 'placeholder:' . $url;
+ } elseif ( '/' === substr( $url, 0, 1 ) ) {
+ $to_unset[] = 'scheme';
+ $to_unset[] = 'host';
+ $url = 'placeholder://placeholder' . $url;
+ }
+
+ $parts = @parse_url( $url );
+
+ if ( false === $parts ) {
+ // Parsing failure.
+ return $parts;
+ }
+
+ // Remove the placeholder values.
+ foreach ( $to_unset as $key ) {
+ unset( $parts[ $key ] );
+ }
+
+ return _get_component_from_parsed_url_array( $parts, $component );
+}
+
+/**
+ * Retrieve a specific component from a parsed URL array.
+ *
+ * @internal
+ *
+ * @since 4.7.0
+ *
+ * @param array|false $url_parts The parsed URL. Can be false if the URL failed to parse.
+ * @param int $component The specific component to retrieve. Use one of the PHP
+ * predefined constants to specify which one.
+ * Defaults to -1 (= return all parts as an array).
+ * @see http://php.net/manual/en/function.parse-url.php
+ * @return mixed False on parse failure; Array of URL components on success;
+ * When a specific component has been requested: null if the component
+ * doesn't exist in the given URL; a sting or - in the case of
+ * PHP_URL_PORT - integer when it does. See parse_url()'s return values.
+ */
+function _get_component_from_parsed_url_array( $url_parts, $component = -1 ) {
+ if ( -1 === $component ) {
+ return $url_parts;
+ }
+
+ $key = _wp_translate_php_url_constant_to_key( $component );
+ if ( false !== $key && is_array( $url_parts ) && isset( $url_parts[ $key ] ) ) {
+ return $url_parts[ $key ];
+ } else {
+ return null;
+ }
+}
+
+/**
+ * Translate a PHP_URL_* constant to the named array keys PHP uses.
+ *
+ * @internal
+ *
+ * @since 4.7.0
+ *
+ * @see http://php.net/manual/en/url.constants.php
+ *
+ * @param int $constant PHP_URL_* constant.
+ * @return string|bool The named key or false.
+ */
+function _wp_translate_php_url_constant_to_key( $constant ) {
+ $translation = array(
+ PHP_URL_SCHEME => 'scheme',
+ PHP_URL_HOST => 'host',
+ PHP_URL_PORT => 'port',
+ PHP_URL_USER => 'user',
+ PHP_URL_PASS => 'pass',
+ PHP_URL_PATH => 'path',
+ PHP_URL_QUERY => 'query',
+ PHP_URL_FRAGMENT => 'fragment',
+ );
+
+ if ( isset( $translation[ $constant ] ) ) {
+ return $translation[ $constant ];
+ } else {
+ return false;
+ }
+}