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<?php |
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|
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/** |
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* The OAuth clients that may ask to be authorized. |
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*/ |
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|
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namespace Extendify\Mcp\OAuth; |
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|
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defined('ABSPATH') || die('No direct access.'); |
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|
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use Extendify\Mcp\Connections; |
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|
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/** |
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* A client id is the https URL of its metadata document, which names the |
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* addresses the client may be sent back to, or an id this site handed out |
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* to a client that registered without one. |
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*/ |
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class Clients |
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{ |
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// phpcs:disable PSR12.Properties.ConstantVisibility.NotFound |
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const CACHE_PREFIX = 'extendify_mcp_client_'; |
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|
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const OPTION = 'extendify_oauth_clients'; |
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|
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/** |
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* Registration is unauthenticated, so the store is bounded. |
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*/ |
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const CAP = 200; |
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|
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const MAX_REDIRECTS = 10; |
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|
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const MAX_REDIRECT_LENGTH = 2048; |
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|
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const IDLE_TTL = 30 * DAY_IN_SECONDS; |
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|
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const LOOPBACK_HOSTS = ['localhost', '127.0.0.1', '[::1]']; |
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// phpcs:enable PSR12.Properties.ConstantVisibility.NotFound |
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|
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/** |
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* @param mixed $clientId - The client_id the request named. |
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* @return array|null |
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*/ |
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public static function find($clientId) |
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{ |
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if (!is_string($clientId) || $clientId === '') { |
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return null; |
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} |
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|
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return self::isDocumentUrl($clientId) ? self::fromDocument($clientId) : self::registered($clientId); |
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} |
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|
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/** |
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* @param string $name - The name the client gave, or '' for none. |
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* @param array $redirectUris - The addresses it may be sent back to, already checked. |
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* @return array - The client as find() returns it. |
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*/ |
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public static function register($name, array $redirectUris) |
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{ |
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$now = time(); |
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$clients = array_filter(self::all(), function ($client) use ($now) { |
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return max($client['created'], $client['lastUsed']) > $now - self::IDLE_TTL; |
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}); |
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uasort($clients, function ($a, $b) { |
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return max($a['created'], $a['lastUsed']) <=> max($b['created'], $b['lastUsed']); |
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}); |
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while (count($clients) >= self::CAP) { |
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array_shift($clients); |
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} |
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|
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$id = \wp_generate_password(32, false, false); |
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$name = \sanitize_text_field($name) ?: \__('Unnamed assistant', 'extendify-local'); |
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$clients[$id] = [ |
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'name' => mb_substr($name, 0, Connections::LABEL_LENGTH), |
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'redirectUris' => array_values($redirectUris), |
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'created' => $now, |
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'lastUsed' => 0, |
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]; |
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\update_option(self::OPTION, $clients, false); |
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|
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return ['id' => $id, 'name' => $clients[$id]['name'], 'redirectUris' => $clients[$id]['redirectUris']]; |
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} |
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|
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/** |
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* Plain http is refused except to the user's own computer: a code sent |
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* over it could be read on the way. |
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* |
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* @param string $uri - A redirect URI a client wants registered. |
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* @return boolean |
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*/ |
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public static function acceptableRedirect($uri) |
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{ |
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if (strlen($uri) > self::MAX_REDIRECT_LENGTH) { |
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return false; |
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} |
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|
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$parts = \wp_parse_url($uri); |
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if (!is_array($parts) || empty($parts['host']) || isset($parts['fragment'])) { |
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return false; |
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} |
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|
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return ($parts['scheme'] ?? '') === 'https' || self::isLoopback($uri); |
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} |
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|
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/** |
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* @param string $url - The client id, an https URL. |
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* @return array|null |
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*/ |
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private static function fromDocument($url) |
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{ |
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$key = self::CACHE_PREFIX . md5($url); |
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$held = \get_transient($key); |
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if (is_array($held)) { |
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return $held; |
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} |
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|
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$client = self::fetch($url); |
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if ($client) { |
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\set_transient($key, $client, HOUR_IN_SECONDS); |
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} |
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|
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return $client; |
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} |
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|
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/** |
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* @param string $id - The client id this site handed out. |
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* @return array|null |
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*/ |
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private static function registered($id) |
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{ |
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$clients = self::all(); |
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if (!isset($clients[$id])) { |
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return null; |
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} |
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|
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$clients[$id]['lastUsed'] = time(); |
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\update_option(self::OPTION, $clients, false); |
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|
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return [ |
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'id' => $id, |
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'name' => $clients[$id]['name'], |
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'redirectUris' => $clients[$id]['redirectUris'], |
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]; |
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} |
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|
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/** |
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* @return array - Registered clients by id. |
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*/ |
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private static function all() |
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{ |
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$clients = \get_option(self::OPTION, []); |
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|
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return is_array($clients) ? $clients : []; |
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} |
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|
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/** |
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* @param array $client - The client as found. |
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* @param string $uri - The redirect_uri the request named, or '' for none. |
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* @return string|null - The address to send the client back to. |
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*/ |
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public static function redirect(array $client, $uri) |
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{ |
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if ($uri === '') { |
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return count($client['redirectUris']) === 1 ? $client['redirectUris'][0] : null; |
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} |
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|
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foreach ($client['redirectUris'] as $registered) { |
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if ($registered === $uri) { |
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return $uri; |
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} |
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|
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// A program on the user's computer binds a fresh port each run (RFC 8252 §7.3). |
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if ( |
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self::isLoopback($registered) && self::isLoopback($uri) |
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&& self::withoutPort($registered) === self::withoutPort($uri) |
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) { |
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return $uri; |
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} |
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} |
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|
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return null; |
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} |
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|
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/** |
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* @param array $client - The client as found. |
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* @return boolean |
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*/ |
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public static function onThisComputerOnly(array $client) |
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{ |
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foreach ($client['redirectUris'] as $uri) { |
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if (!self::isLoopback($uri)) { |
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return false; |
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} |
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} |
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|
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return true; |
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} |
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|
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/** |
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* @param string $uri - A redirect URI. |
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* @return boolean |
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*/ |
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private static function isLoopback($uri) |
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{ |
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$parts = \wp_parse_url($uri); |
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|
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return is_array($parts) |
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&& ($parts['scheme'] ?? '') === 'http' |
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&& in_array($parts['host'] ?? '', self::LOOPBACK_HOSTS, true); |
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} |
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|
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/** |
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* @param string $uri - A loopback redirect URI. |
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* @return string |
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*/ |
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private static function withoutPort($uri) |
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{ |
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return preg_replace('#^(http://(?:\[[^\]]+\]|[^/:]+)):\d+#', '$1', $uri); |
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} |
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|
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/** |
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* @param string $url - The client id. |
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* @return boolean |
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*/ |
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private static function isDocumentUrl($url) |
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{ |
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$parts = \wp_parse_url($url); |
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|
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return is_array($parts) |
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&& ($parts['scheme'] ?? '') === 'https' |
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&& !empty($parts['host']) |
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&& !isset($parts['fragment']) |
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&& !isset($parts['user']) |
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&& !isset($parts['pass']); |
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} |
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|
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/** |
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* @param string $url - The client id. |
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* @return array|null |
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*/ |
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private static function fetch($url) |
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{ |
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$response = \wp_safe_remote_get($url, [ |
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'timeout' => 5, |
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// A redirected document could not claim the URL it was fetched from. |
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'redirection' => 0, |
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'limit_response_size' => 64 * KB_IN_BYTES, |
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'headers' => ['Accept' => 'application/json'], |
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]); |
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if (\is_wp_error($response) || \wp_remote_retrieve_response_code($response) !== 200) { |
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return null; |
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} |
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|
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$document = json_decode(\wp_remote_retrieve_body($response), true); |
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if (!is_array($document) || ($document['client_id'] ?? null) !== $url) { |
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return null; |
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} |
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|
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$uris = is_array($document['redirect_uris'] ?? null) ? $document['redirect_uris'] : []; |
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$uris = array_values(array_filter($uris, function ($uri) { |
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return is_string($uri) && self::acceptableRedirect($uri); |
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})); |
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if (!$uris) { |
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return null; |
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} |
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|
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$name = is_string($document['client_name'] ?? null) ? \sanitize_text_field($document['client_name']) : ''; |
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|
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return [ |
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'id' => $url, |
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'name' => mb_substr($name ?: (string) \wp_parse_url($url, PHP_URL_HOST), 0, Connections::LABEL_LENGTH), |
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'redirectUris' => $uris, |
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]; |
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} |
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} |
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|
