zip-ai / lib / mcp-adapter / includes / Transport / Infrastructure / SessionManager.php

SessionManager.php in ZIP AI – AI Website Builder & AI Agent (Beta) 0.0.8, at lib/mcp-adapter/includes/Transport/Infrastructure/SessionManager.php

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1	<?php
2	/**
3	* MCP Session Manager using User Meta
4	*
5	*
6	* @package McpAdapter
7	*/
8
9	declare( strict_types=1 );
10
11	namespace WP\MCP\Transport\Infrastructure;
12
13	use WP_Error;
14
15	/**
16	* MCP Session Manager
17	*
18	* Handles session creation, validation, and cleanup using user meta storage.
19	* Sessions are tied to authenticated users to prevent anonymous session flooding.
20	*/
21	final class SessionManager {
22
23	/**
24	* User meta key for storing sessions
25	*
26	* @var string
27	*/
28	private const SESSION_META_KEY = 'mcp_adapter_sessions';
29
30	/**
31	* Maximum sessions per user.
32	*
33	* @var int
34	*/
35	private const DEFAULT_MAX_SESSIONS = 32;
36
37	/**
38	* Session inactivity timeout in seconds (24 hours).
39	*
40	* @var int
41	*/
42	private const DEFAULT_INACTIVITY_TIMEOUT = DAY_IN_SECONDS;
43
44	/**
45	* Minimum interval between last_activity writes in seconds.
46	*
47	* @var int
48	*/
49	private const DEFAULT_ACTIVITY_UPDATE_INTERVAL = 60;
50
51	/**
52	* Create a new session for a user
53	*
54	* @param int $user_id The user ID.
55	* @param array $params Client parameters from initialize request.
56	*
57	* @return string\|false The session ID on success, false on failure.
58	*/
59	public static function create_session( int $user_id, array $params = array() ) {
60	if ( ! $user_id \|\| ! get_user_by( 'id', $user_id ) ) {
61	return false;
62	}
63
64	// Cleanup inactive sessions first
65	self::cleanup_expired_sessions( $user_id );
66
67	// Get current sessions
68	$sessions = self::get_all_user_sessions( $user_id );
69
70	// Check session limit - remove oldest if over limit
71	$config = self::get_config();
72	$max_sessions = $config['max_sessions'];
73	if ( count( $sessions ) >= $max_sessions ) {
74	// Remove oldest session (FIFO) - sort by created_at and remove first
75	uasort(
76	$sessions,
77	static function ( $a, $b ) {
78	return $a['created_at'] <=> $b['created_at'];
79	}
80	);
81
82	array_shift( $sessions );
83	}
84
85	// Create a new session
86	$session_id = wp_generate_uuid4();
87	$now = time();
88
89	$sessions[ $session_id ] = array(
90	'created_at' => $now,
91	'last_activity' => $now,
92	'client_params' => $params,
93	);
94
95	// Save sessions
96	update_user_meta( $user_id, self::SESSION_META_KEY, $sessions );
97
98	return $session_id;
99	}
100
101	/**
102	* Cleanup inactive sessions for a user
103	*
104	* @param int $user_id The user ID.
105	*
106	* @return int Number of sessions removed.
107	*/
108	public static function cleanup_expired_sessions( int $user_id ): int {
109	if ( ! $user_id ) {
110	return 0;
111	}
112
113	$sessions = self::get_all_user_sessions( $user_id );
114	$now = time();
115	$removed = 0;
116
117	$config = self::get_config();
118	$inactivity_timeout = $config['inactivity_timeout'];
119
120	foreach ( $sessions as $session_id => $session ) {
121	// Check if still active - skip if valid
122	if ( $session['last_activity'] + $inactivity_timeout >= $now ) {
123	continue;
124	}
125
126	// Session is inactive - remove it
127	unset( $sessions[ $session_id ] );
128	++$removed;
129	}
130
131	if ( $removed > 0 ) {
132	if ( empty( $sessions ) ) {
133	delete_user_meta( $user_id, self::SESSION_META_KEY );
134	} else {
135	update_user_meta( $user_id, self::SESSION_META_KEY, $sessions );
136	}
137	}
138
139	return $removed;
140	}
141
142	/**
143	* Get all sessions for a user
144	*
145	* @param int $user_id The user ID.
146	*
147	* @return array Array of sessions.
148	*/
149	public static function get_all_user_sessions( int $user_id ): array {
150	if ( ! $user_id ) {
151	return array();
152	}
153
154	$sessions = get_user_meta( $user_id, self::SESSION_META_KEY, true );
155
156	if ( ! is_array( $sessions ) ) {
157	return array();
158	}
159
160	return $sessions;
161	}
162
163	/**
164	* Get configuration values.
165	*
166	* @return array{max_sessions: int, inactivity_timeout: int, activity_update_interval: int} Configuration array.
167	*/
168	private static function get_config(): array {
169	/**
170	* Filters the maximum number of MCP sessions allowed per user.
171	*
172	* When a user exceeds this limit, the oldest inactive session is
173	* automatically removed to make room for new sessions.
174	*
175	* @since 0.3.0
176	*
177	* @param int $max_sessions Maximum sessions per user. Default 32.
178	*/
179	$max_sessions = (int) apply_filters( 'mcp_adapter_session_max_per_user', self::DEFAULT_MAX_SESSIONS );
180
181	/**
182	* Filters the session inactivity timeout in seconds.
183	*
184	* Sessions that have been inactive longer than this duration are
185	* considered expired and may be cleaned up automatically.
186	*
187	* @since 0.3.0
188	*
189	* @param int $timeout Inactivity timeout in seconds. Default DAY_IN_SECONDS (86400 / 24 hours).
190	*/
191	$inactivity_timeout = (int) apply_filters( 'mcp_adapter_session_inactivity_timeout', self::DEFAULT_INACTIVITY_TIMEOUT );
192
193	/**
194	* Filters the minimum interval between session last_activity writes.
195	*
196	* To reduce write amplification, the session manager only updates
197	* `last_activity` if at least this many seconds have elapsed since
198	* the last write.
199	*
200	* @since 0.5.0
201	*
202	* @param int $interval Minimum seconds between writes. Default 60.
203	*/
204	$activity_update_interval = (int) apply_filters( 'mcp_adapter_session_activity_update_interval', self::DEFAULT_ACTIVITY_UPDATE_INTERVAL );
205
206	// Clamp: interval must be less than inactivity timeout to prevent
207	// sessions from expiring despite active use.
208	if ( $activity_update_interval >= $inactivity_timeout ) {
209	$activity_update_interval = (int) ( $inactivity_timeout / 2 );
210	}
211
212	return array(
213	'max_sessions' => $max_sessions,
214	'inactivity_timeout' => $inactivity_timeout,
215	'activity_update_interval' => max( 0, $activity_update_interval ),
216	);
217	}
218
219	/**
220	* Get a specific session for a user
221	*
222	* @param int $user_id The user ID.
223	* @param string $session_id The session ID.
224	*
225	* @return array\|\WP_Error\|false Session data on success, WP_Error on invalid input, false if not found or inactive.
226	*/
227	public static function get_session( int $user_id, string $session_id ) {
228	if ( ! $user_id \|\| ! $session_id ) {
229	return new WP_Error( 'mcp_session_invalid_input', 'Invalid user ID or session ID.' );
230	}
231
232	$sessions = self::get_all_user_sessions( $user_id );
233
234	if ( ! isset( $sessions[ $session_id ] ) ) {
235	return false;
236	}
237
238	$session = $sessions[ $session_id ];
239
240	// Check inactivity timeout
241	$config = self::get_config();
242	$inactivity_timeout = $config['inactivity_timeout'];
243	if ( $session['last_activity'] + $inactivity_timeout < time() ) {
244	self::clear_session( $user_id, $session_id );
245
246	return false;
247	}
248
249	return $session;
250	}
251
252	/**
253	* Clear an inactive session (internal cleanup).
254	*
255	* @param int $user_id The user ID.
256	* @param string $session_id The session ID to clear.
257	*
258	* @return void
259	*/
260	private static function clear_session( int $user_id, string $session_id ): void {
261	$sessions = self::get_all_user_sessions( $user_id );
262
263	if ( ! isset( $sessions[ $session_id ] ) ) {
264	return;
265	}
266
267	unset( $sessions[ $session_id ] );
268	update_user_meta( $user_id, self::SESSION_META_KEY, $sessions );
269	}
270
271	/**
272	* Validate a session and update last activity
273	*
274	* @param int $user_id The user ID.
275	* @param string $session_id The session ID.
276	*
277	* @return bool True if valid, false otherwise.
278	*/
279	public static function validate_session( int $user_id, string $session_id ): bool {
280	if ( ! $user_id \|\| ! $session_id ) {
281	return false;
282	}
283
284	$sessions = self::get_all_user_sessions( $user_id );
285
286	if ( ! isset( $sessions[ $session_id ] ) ) {
287	return false;
288	}
289
290	$session = $sessions[ $session_id ];
291
292	// Check inactivity timeout
293	$config = self::get_config();
294	$inactivity_timeout = $config['inactivity_timeout'];
295	if ( $session['last_activity'] + $inactivity_timeout < time() ) {
296	self::clear_session( $user_id, $session_id );
297
298	return false;
299	}
300
301	// Throttle last_activity writes to reduce write amplification
302	$activity_update_interval = $config['activity_update_interval'];
303	if ( time() - $session['last_activity'] >= $activity_update_interval ) {
304	$sessions[ $session_id ]['last_activity'] = time();
305	update_user_meta( $user_id, self::SESSION_META_KEY, $sessions );
306	}
307
308	return true;
309	}
310
311	/**
312	* Delete a specific session
313	*
314	* @param int $user_id The user ID.
315	* @param string $session_id The session ID.
316	*
317	* @return bool True on success, false on failure.
318	*/
319	public static function delete_session( int $user_id, string $session_id ): bool {
320	if ( ! $user_id \|\| ! $session_id ) {
321	return false;
322	}
323
324	$sessions = self::get_all_user_sessions( $user_id );
325
326	if ( ! isset( $sessions[ $session_id ] ) ) {
327	return false;
328	}
329
330	unset( $sessions[ $session_id ] );
331
332	if ( empty( $sessions ) ) {
333	delete_user_meta( $user_id, self::SESSION_META_KEY );
334	} else {
335	update_user_meta( $user_id, self::SESSION_META_KEY, $sessions );
336	}
337
338	return true;
339	}
340	}
341