<?php

/**

 * HTTP API: WP_HTTP_Proxy class

 *

 * @package WordPress

 * @subpackage HTTP

 * @since 4.4.0

 */

/**

 * Core class used to implement HTTP API proxy support.

 *

 * There are caveats to proxy support. It requires that defines be made in the wp-config.php file to

 * enable proxy support. There are also a few filters that plugins can hook into for some of the

 * constants.

 *

 * Please note that only BASIC authentication is supported by most transports.

 * cURL MAY support more methods (such as NTLM authentication) depending on your environment.

 *

 * The constants are as follows:

 * <ol>

 * <li>WP_PROXY_HOST - Enable proxy support and host for connecting.</li>

 * <li>WP_PROXY_PORT - Proxy port for connection. No default, must be defined.</li>

 * <li>WP_PROXY_USERNAME - Proxy username, if it requires authentication.</li>

 * <li>WP_PROXY_PASSWORD - Proxy password, if it requires authentication.</li>

 * <li>WP_PROXY_BYPASS_HOSTS - Will prevent the hosts in this list from going through the proxy.

 * You do not need to have localhost and the site host in this list, because they will not be passed

 * through the proxy. The list should be presented in a comma separated list, wildcards using * are supported, eg. *.wordpress.org</li>

 * </ol>

 *

 * An example can be as seen below.

 *

 *     define('WP_PROXY_HOST', '192.168.84.101');

 *     define('WP_PROXY_PORT', '8080');

 *     define('WP_PROXY_BYPASS_HOSTS', 'localhost, www.example.com, *.wordpress.org');

 *

 * @link https://core.trac.wordpress.org/ticket/4011 Proxy support ticket in WordPress.

 * @link https://core.trac.wordpress.org/ticket/14636 Allow wildcard domains in WP_PROXY_BYPASS_HOSTS

 *

 * @since 2.8.0

 */

class WP_HTTP_Proxy {

	/**

	 * Whether proxy connection should be used.

	 *

	 * @since 2.8.0

	 *

	 * @use WP_PROXY_HOST

	 * @use WP_PROXY_PORT

	 *

	 * @return bool

	 */

	public function is_enabled() {

		return defined('WP_PROXY_HOST') && defined('WP_PROXY_PORT');

	}

	/**

	 * Whether authentication should be used.

	 *

	 * @since 2.8.0

	 *

	 * @use WP_PROXY_USERNAME

	 * @use WP_PROXY_PASSWORD

	 *

	 * @return bool

	 */

	public function use_authentication() {

		return defined('WP_PROXY_USERNAME') && defined('WP_PROXY_PASSWORD');

	}

	/**

	 * Retrieve the host for the proxy server.

	 *

	 * @since 2.8.0

	 *

	 * @return string

	 */

	public function host() {

		if ( defined('WP_PROXY_HOST') )

			return WP_PROXY_HOST;

		return '';

	}

	/**

	 * Retrieve the port for the proxy server.

	 *

	 * @since 2.8.0

	 *

	 * @return string

	 */

	public function port() {

		if ( defined('WP_PROXY_PORT') )

			return WP_PROXY_PORT;

		return '';

	}

	/**

	 * Retrieve the username for proxy authentication.

	 *

	 * @since 2.8.0

	 *

	 * @return string

	 */

	public function username() {

		if ( defined('WP_PROXY_USERNAME') )

			return WP_PROXY_USERNAME;

		return '';

	}

	/**

	 * Retrieve the password for proxy authentication.

	 *

	 * @since 2.8.0

	 *

	 * @return string

	 */

	public function password() {

		if ( defined('WP_PROXY_PASSWORD') )

			return WP_PROXY_PASSWORD;

		return '';

	}

	/**

	 * Retrieve authentication string for proxy authentication.

	 *

	 * @since 2.8.0

	 *

	 * @return string

	 */

	public function authentication() {

		return $this->username() . ':' . $this->password();

	}

	/**

	 * Retrieve header string for proxy authentication.

	 *

	 * @since 2.8.0

	 *

	 * @return string

	 */

	public function authentication_header() {

		return 'Proxy-Authorization: Basic ' . base64_encode( $this->authentication() );

	}

	/**

	 * Whether URL should be sent through the proxy server.

	 *

	 * We want to keep localhost and the site URL from being sent through the proxy server, because

	 * some proxies can not handle this. We also have the constant available for defining other

	 * hosts that won't be sent through the proxy.

	 *

	 * @since 2.8.0

	 *

	 * @staticvar array|null $bypass_hosts

	 * @staticvar array      $wildcard_regex

	 *

	 * @param string $uri URI to check.

	 * @return bool True, to send through the proxy and false if, the proxy should not be used.

	 */

	public function send_through_proxy( $uri ) {

		/*

		 * parse_url() only handles http, https type URLs, and will emit E_WARNING on failure.

		 * This will be displayed on sites, which is not reasonable.

		 */

		$check = @parse_url($uri);

		// Malformed URL, can not process, but this could mean ssl, so let through anyway.

		if ( $check === false )

			return true;

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

		/**

		 * Filters whether to preempt sending the request through the proxy server.

		 *

		 * Returning false will bypass the proxy; returning true will send

		 * the request through the proxy. Returning null bypasses the filter.

		 *

		 * @since 3.5.0

		 *

		 * @param null   $override Whether to override the request result. Default null.

		 * @param string $uri      URL to check.

		 * @param array  $check    Associative array result of parsing the URI.

		 * @param array  $home     Associative array result of parsing the site URL.

		 */

		$result = apply_filters( 'pre_http_send_through_proxy', null, $uri, $check, $home );

		if ( ! is_null( $result ) )

			return $result;

		if ( 'localhost' == $check['host'] || ( isset( $home['host'] ) && $home['host'] == $check['host'] ) )

			return false;

		if ( !defined('WP_PROXY_BYPASS_HOSTS') )

			return true;

		static $bypass_hosts = null;

		static $wildcard_regex = array();

		if ( null === $bypass_hosts ) {

			$bypass_hosts = preg_split('|,\s*|', WP_PROXY_BYPASS_HOSTS);

			if ( false !== strpos(WP_PROXY_BYPASS_HOSTS, '*') ) {

				$wildcard_regex = array();

				foreach ( $bypass_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'], $bypass_hosts );

	}

}