1<?php
  2/**
  3 * HTTP API: WP_HTTP_Proxy class
  4 *
  5 * @package WordPress
  6 * @subpackage HTTP
  7 * @since 4.4.0
  8 */
  9
 10/**
 11 * Core class used to implement HTTP API proxy support.
 12 *
 13 * There are caveats to proxy support. It requires that defines be made in the wp-config.php file to
 14 * enable proxy support. There are also a few filters that plugins can hook into for some of the
 15 * constants.
 16 *
 17 * Please note that only BASIC authentication is supported by most transports.
 18 * cURL MAY support more methods (such as NTLM authentication) depending on your environment.
 19 *
 20 * The constants are as follows:
 21 * <ol>
 22 * <li>WP_PROXY_HOST - Enable proxy support and host for connecting.</li>
 23 * <li>WP_PROXY_PORT - Proxy port for connection. No default, must be defined.</li>
 24 * <li>WP_PROXY_USERNAME - Proxy username, if it requires authentication.</li>
 25 * <li>WP_PROXY_PASSWORD - Proxy password, if it requires authentication.</li>
 26 * <li>WP_PROXY_BYPASS_HOSTS - Will prevent the hosts in this list from going through the proxy.
 27 * You do not need to have localhost and the site host in this list, because they will not be passed
 28 * through the proxy. The list should be presented in a comma separated list, wildcards using * are supported. Example: *.wordpress.org</li>
 29 * </ol>
 30 *
 31 * An example can be as seen below.
 32 *
 33 *     define('WP_PROXY_HOST', '192.168.84.101');
 34 *     define('WP_PROXY_PORT', '8080');
 35 *     define('WP_PROXY_BYPASS_HOSTS', 'localhost, www.example.com, *.wordpress.org');
 36 *
 37 * @link https://core.trac.wordpress.org/ticket/4011 Proxy support ticket in WordPress.
 38 * @link https://core.trac.wordpress.org/ticket/14636 Allow wildcard domains in WP_PROXY_BYPASS_HOSTS
 39 *
 40 * @since 2.8.0
 41 */
 42#[AllowDynamicProperties]
 43class WP_HTTP_Proxy {
 44
 45	/**
 46	 * Whether proxy connection should be used.
 47	 *
 48	 * Constants which control this behavior:
 49	 *
 50	 * - `WP_PROXY_HOST`
 51	 * - `WP_PROXY_PORT`
 52	 *
 53	 * @since 2.8.0
 54	 *
 55	 * @return bool
 56	 */
 57	public function is_enabled() {
 58		return defined( 'WP_PROXY_HOST' ) && defined( 'WP_PROXY_PORT' );
 59	}
 60
 61	/**
 62	 * Whether authentication should be used.
 63	 *
 64	 * Constants which control this behavior:
 65	 *
 66	 * - `WP_PROXY_USERNAME`
 67	 * - `WP_PROXY_PASSWORD`
 68	 *
 69	 * @since 2.8.0
 70	 *
 71	 * @return bool
 72	 */
 73	public function use_authentication() {
 74		return defined( 'WP_PROXY_USERNAME' ) && defined( 'WP_PROXY_PASSWORD' );
 75	}
 76
 77	/**
 78	 * Retrieve the host for the proxy server.
 79	 *
 80	 * @since 2.8.0
 81	 *
 82	 * @return string
 83	 */
 84	public function host() {
 85		if ( defined( 'WP_PROXY_HOST' ) ) {
 86			return WP_PROXY_HOST;
 87		}
 88
 89		return '';
 90	}
 91
 92	/**
 93	 * Retrieve the port for the proxy server.
 94	 *
 95	 * @since 2.8.0
 96	 *
 97	 * @return string
 98	 */
 99	public function port() {
100		if ( defined( 'WP_PROXY_PORT' ) ) {
101			return WP_PROXY_PORT;
102		}
103
104		return '';
105	}
106
107	/**
108	 * Retrieve the username for proxy authentication.
109	 *
110	 * @since 2.8.0
111	 *
112	 * @return string
113	 */
114	public function username() {
115		if ( defined( 'WP_PROXY_USERNAME' ) ) {
116			return WP_PROXY_USERNAME;
117		}
118
119		return '';
120	}
121
122	/**
123	 * Retrieve the password for proxy authentication.
124	 *
125	 * @since 2.8.0
126	 *
127	 * @return string
128	 */
129	public function password() {
130		if ( defined( 'WP_PROXY_PASSWORD' ) ) {
131			return WP_PROXY_PASSWORD;
132		}
133
134		return '';
135	}
136
137	/**
138	 * Retrieve authentication string for proxy authentication.
139	 *
140	 * @since 2.8.0
141	 *
142	 * @return string
143	 */
144	public function authentication() {
145		return $this->username() . ':' . $this->password();
146	}
147
148	/**
149	 * Retrieve header string for proxy authentication.
150	 *
151	 * @since 2.8.0
152	 *
153	 * @return string
154	 */
155	public function authentication_header() {
156		return 'Proxy-Authorization: Basic ' . base64_encode( $this->authentication() );
157	}
158
159	/**
160	 * Determines whether the request should be sent through a proxy.
161	 *
162	 * We want to keep localhost and the site URL from being sent through the proxy, because
163	 * some proxies can not handle this. We also have the constant available for defining other
164	 * hosts that won't be sent through the proxy.
165	 *
166	 * @since 2.8.0
167	 *
168	 * @param string $uri URL of the request.
169	 * @return bool Whether to send the request through the proxy.
170	 */
171	public function send_through_proxy( $uri ) {
172		$check = parse_url( $uri );
173
174		// Malformed URL, can not process, but this could mean ssl, so let through anyway.
175		if ( false === $check ) {
176			return true;
177		}
178
179		$home = parse_url( get_option( 'siteurl' ) );
180
181		/**
182		 * Filters whether to preempt sending the request through the proxy.
183		 *
184		 * Returning false will bypass the proxy; returning true will send
185		 * the request through the proxy. Returning null bypasses the filter.
186		 *
187		 * @since 3.5.0
188		 *
189		 * @param bool|null $override Whether to send the request through the proxy. Default null.
190		 * @param string    $uri      URL of the request.
191		 * @param array     $check    Associative array result of parsing the request URL with `parse_url()`.
192		 * @param array     $home     Associative array result of parsing the site URL with `parse_url()`.
193		 */
194		$result = apply_filters( 'pre_http_send_through_proxy', null, $uri, $check, $home );
195		if ( ! is_null( $result ) ) {
196			return $result;
197		}
198
199		if ( 'localhost' === $check['host'] || ( isset( $home['host'] ) && $home['host'] === $check['host'] ) ) {
200			return false;
201		}
202
203		if ( ! defined( 'WP_PROXY_BYPASS_HOSTS' ) ) {
204			return true;
205		}
206
207		static $bypass_hosts   = null;
208		static $wildcard_regex = array();
209		if ( null === $bypass_hosts ) {
210			$bypass_hosts = preg_split( '|,\s*|', WP_PROXY_BYPASS_HOSTS );
211
212			if ( str_contains( WP_PROXY_BYPASS_HOSTS, '*' ) ) {
213				$wildcard_regex = array();
214				foreach ( $bypass_hosts as $host ) {
215					$wildcard_regex[] = str_replace( '\*', '.+', preg_quote( $host, '/' ) );
216				}
217				$wildcard_regex = '/^(' . implode( '|', $wildcard_regex ) . ')$/i';
218			}
219		}
220
221		if ( ! empty( $wildcard_regex ) ) {
222			return ! preg_match( $wildcard_regex, $check['host'] );
223		} else {
224			return ! in_array( $check['host'], $bypass_hosts, true );
225		}
226	}
227}
228