* @link https://core.trac.wordpress.org/ticket/14636 Allow wildcard domains in WP_ACCESSIBLE_HOSTS
	 *
	 * @staticvar array|null $accessible_hosts
	 * @staticvar array      $wildcard_regex
	 *
	 * @param string $uri URI of url.
	 * @return bool True to block, false to allow.
	 */
	public function block_request($uri) {
		// We don't need to block requests, because nothing is blocked.
		if ( ! defined( 'WP_HTTP_BLOCK_EXTERNAL' ) || ! WP_HTTP_BLOCK_EXTERNAL )
			return false;

		$check = parse_url($uri);
		if ( ! $check )
			return true;

		$home = parse_url( get_option('siteurl') );

		// Don't block requests back to ourselves by default.
		if ( 'localhost' == $check['host'] || ( isset( $home['host'] ) && $home['host'] == $check['host'] ) ) {
			/**
			 * Filters whether to block local requests through the proxy.
			 *
			 * @since 2.8.0
			 *
			 * @param bool $block Whether to block local requests through proxy.
			 *                    Default false.
			 */
			return apply_filters( 'block_local_requests', false );
		}

		if ( !defined('WP_ACCESSIBLE_HOSTS') )
			return true;

		static $accessible_hosts = null;
		static $wildcard_regex = array();
		if ( null === $accessible_hosts ) {
			$accessible_hosts = preg_split('|,\s*|', WP_ACCESSIBLE_HOSTS);

			if ( false !== strpos(WP_ACCESSIBLE_HOSTS, '*') ) {
				$wildcard_regex = array();
				foreach ( $accessible_hosts as $host )
					$wildcard_regex[] = str_replace( '\*', '.+', preg_quote( $host, '/' ) );
				$wildcard_regex = '/^(' . implode('|', $wildcard_regex) . ')$/i';
			}
		}

		if ( !empty($wildcard_regex) )
			return !preg_match($wildcard_regex, $check['host']);
		else
			return !in_array( $check['host'], $accessible_hosts ); //Inverse logic, If it's in the array, then we can't access it.

	}

	/**
	 * Used as a wrapper for PHP's parse_url() function that handles edgecases in < PHP 5.4.7.
	 *
	 * @deprecated 4.4.0 Use wp_parse_url()
	 * @see wp_parse_url()
	 *
	 * @param string $url The URL to parse.
	 * @return bool|array False on failure; Array of URL components on success;
	 *                    See parse_url()'s return values.
	 */
	protected static function parse_url( $url ) {
		_deprecated_function( __METHOD__, '4.4.0', 'wp_parse_url()' );
		return wp_parse_url( $url );
	}

	/**
	 * Converts a relative URL to an absolute URL relative to a given URL.
	 *
	 * If an Absolute URL is provided, no processing of that URL is done.
	 *
	 * @since 3.4.0
	 *
	 * @static
	 *
	 * @param string $maybe_relative_path The URL which might be relative
	 * @param string $url                 The URL which $maybe_relative_path is relative to
	 * @return string An Absolute URL, in a failure condition where the URL cannot be parsed, the relative URL will be returned.
	 */
	public static function make_absolute_url( $maybe_relative_path, $url ) {
		if ( empty( $url ) )
			return $maybe_relative_path;

		if ( ! $url_parts = wp_parse_url( $url ) ) {
			return $maybe_relative_path;
		}

		if ( ! $relative_url_parts = wp_parse_url( $maybe_relative_path ) ) {
			return $maybe_relative_path;
		}

		// Check for a scheme on the 'relative' url
		if ( ! empty( $relative_url_parts['scheme'] ) ) {
			return $maybe_relative_path;
		}

		$absolute_path = $url_parts['scheme'] . '://';

		// Schemeless URL's will make it this far, so we check for a host in the relative url and convert it to a protocol-url
		if ( isset( $relative_url_parts['host'] ) ) {
			$absolute_path .= $relative_url_parts['host'];
			if ( isset( $relative_url_parts['port'] ) )
				$absolute_path .= ':' . $relative_url_parts['port'];
		} else {
			$absolute_path .= $url_parts['host'];
			if ( isset( $url_parts['port'] ) )
				$absolute_path .= ':' . $url_parts['port'];
		}

		// Start off with the Absolute URL path.
		$path = ! empty( $url_parts['path'] ) ? $url_parts['path'] : '/';

		// If it's a root-relative path, then great.
		if ( ! empty( $relative_url_parts['path'] ) && '/' == $relative_url_parts['path'][0] ) {
			$path = $relative_url_parts['path'];

		// Else it's a relative path.
		} elseif ( ! empty( $relative_url_parts['path'] ) ) {
			// Strip off any file components from the absolute path.
			$path = substr( $path, 0, strrpos( $path, '/' ) + 1 );

			// Build the new path.
			$path .= $relative_url_parts['path'];

			// Strip all /path/../ out of the path.
			while ( strpos( $path, '../' ) > 1 ) {
				$path = preg_replace( '![^/]+/\.\./!', '', $path );
			}

			// Strip any final leading ../ from the path.
			$path = preg_replace( '!^/(\.\./)+!', '', $path );
		}

		// Add the Query string.
		if ( ! empty( $relative_url_parts['query'] ) )
			$path .= '?' . $relative_url_parts['query'];

		return $absolute_path . '/' . ltrim( $path, '/' );
	}

	/**
	 * Handles HTTP Redirects and follows them if appropriate.
	 *
	 * @since 3.7.0
	 * @static
	 *
	 * @param string $url The URL which was requested.
	 * @param array $args The Arguments which were used to make the request.
	 * @param array $response The Response of the HTTP request.
	 * @return false|object False if no redirect is present, a WP_HTTP or WP_Error result otherwise.
	 */
	public static function handle_redirects( $url, $args, $response ) {
		// If no redirects are present, or, redirects were not requested, perform no action.
		if ( ! isset( $response['headers']['location'] ) || 0 === $args['_redirection'] )
			return false;

		// Only perform redirections on redirection http codes.
		if ( $response['response']['code'] > 399 || $response['response']['code'] < 300 )
			return false;

		// Don't redirect if we've run out of redirects.
		if ( $args['redirection']-- <= 0 )
			return new WP_Error( 'http_request_failed', __('Too many redirects.') );

		$redirect_location = $response['headers']['location'];

		// If there were multiple Location headers, use the last header specified.
		if ( is_array( $redirect_location ) )
			$redirect_location = array_pop( $redirect_location );

		$redirect_location = WP_Http::make_absolute_url( $redirect_location, $url );

		// POST requests should not POST to a redirected location.
		if ( 'POST' == $args['method'] ) {
			if ( in_array( $response['response']['code'], array( 302, 303 ) ) )
				$args['method'] = 'GET';
		}

		// Include valid cookies in the redirect process.
		if ( ! empty( $response['cookies'] ) ) {
			foreach ( $response['cookies'] as $cookie ) {
				if ( $cookie->test( $redirect_location ) )
					$args['cookies'][] = $cookie;
			}
		}

		return wp_remote_request( $redirect_location, $args );
	}

	/**
	 * Determines if a specified string represents an IP address or not.
	 *
	 * This function also detects the type of the IP address, returning either
	 * '4' or '6' to represent a IPv4 and IPv6 address respectively.
	 * This does not verify if the IP is a valid IP, only that it appears to be
	 * an IP address.
	 *
	 * @link http://home.deds.nl/~aeron/regex/ for IPv6 regex
	 *
	 * @since 3.7.0
	 * @static
	 *
	 * @param string $maybe_ip A suspected IP address
	 * @return integer|bool Upon success, '4' or '6' to represent a IPv4 or IPv6 address, false upon failure
	 */
	public static function is_ip_address( $maybe_ip ) {
		if ( preg_match( '/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/', $maybe_ip ) )
			return 4;

		if ( false !== strpos( $maybe_ip, ':' ) && preg_match( '/^(((?=.*(::))(?!.*\3.+\3))\3?|([\dA-F]{1,4}(\3|:\b|$)|\2))(?4){5}((?4){2}|(((2[0-4]|1\d|[1-9])?\d|25[0-5])\.?\b){4})$/i', trim( $maybe_ip, ' []' ) ) )
			return 6;

		return false;
	}

}