woocommerce-pos / includes / Services / Cloud_Print_Registry.php

Cloud_Print_Registry.php in WCPOS – Point of Sale (POS) plugin for WooCommerce 1.10.13, at includes/Services/Cloud_Print_Registry.php

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1	<?php
2	/**
3	* Cloud printer registry (reads woocommerce_pos_settings_cloud_print).
4	*
5	* @package WCPOS\WooCommercePOS\Services
6	*/
7
8	namespace WCPOS\WooCommercePOS\Services;
9
10	/**
11	* Cloud_Print_Registry class.
12	*/
13	class Cloud_Print_Registry {
14	const OPTION = 'woocommerce_pos_settings_cloud_print';
15
16	const RUNTIME_OPTION = 'woocommerce_pos_cloud_print_runtime';
17	const SEEN_TTL = 150; // Seconds; connected if seen within this window.
18	const PN_STATUS_TTL = 60; // Seconds; PrintNode live-status cache window.
19
20	/**
21	* Per-printer CloudPRNT client capabilities, keyed by printer id.
22	*
23	* Separate from RUNTIME_OPTION, whose values are bare last-seen timestamps.
24	*/
25	const CAPABILITIES_OPTION = 'woocommerce_pos_cloud_print_capabilities';
26
27	/**
28	* Seconds before a printer's capability answers are asked for again.
29	*
30	* Star's own WooCommerce plugin re-asks every 120 seconds; matching it keeps
31	* a swapped-out printer on a reused id from serving formats the new hardware
32	* cannot decode for longer than a couple of minutes.
33	*/
34	const CAPABILITIES_TTL = 120;
35
36	/**
37	* Mutex guarding read-modify-write of the shared capabilities option.
38	*/
39	const CAPABILITIES_LOCK = 'wcpos_cloud_print_caps_lock';
40
41	/**
42	* Seconds after which a capabilities lock is treated as abandoned.
43	*
44	* Short on purpose: the critical section is one option write, so a lock
45	* older than this belongs to a request that died holding it.
46	*/
47	const CAPABILITIES_LOCK_TTL = 10;
48
49	/**
50	* All registered cloud printers.
51	*
52	* @return array<int, array>
53	*/
54	public function get_printers(): array {
55	$settings = get_option( self::OPTION, array() );
56
57	return isset( $settings['printers'] ) && \is_array( $settings['printers'] ) ? $settings['printers'] : array();
58	}
59
60	/**
61	* Get a registered cloud printer by id.
62	*
63	* @param string $printer_id Printer id.
64	*
65	* @return array\|null
66	*/
67	public function get_printer( string $printer_id ): ?array {
68	foreach ( $this->get_printers() as $printer ) {
69	if ( isset( $printer['id'] ) && hash_equals( (string) $printer['id'], $printer_id ) ) {
70	return $printer;
71	}
72	}
73
74	return null;
75	}
76
77	/**
78	* Verify a printer's poll token (constant-time).
79	*
80	* @param string $printer_id Printer id.
81	* @param string $token Presented token.
82	*/
83	public function verify_token( string $printer_id, string $token ): bool {
84	$printer = $this->get_printer( $printer_id );
85	if ( null === $printer \|\| empty( $printer['poll_token_hash'] ) \|\| '' === $token ) {
86	return false;
87	}
88
89	return hash_equals( (string) $printer['poll_token_hash'], self::hash_token( $token ) );
90	}
91
92	/**
93	* Generate a cryptographically strong poll token (returned to the admin once).
94	*/
95	public static function generate_token(): string {
96	return bin2hex( random_bytes( 24 ) );
97	}
98
99	/**
100	* Hash a poll token for at-rest storage (we never persist the plaintext).
101	*
102	* @param string $token Token.
103	*/
104	public static function hash_token( string $token ): string {
105	return hash( 'sha256', $token );
106	}
107
108	/**
109	* Derive a stable, URL-safe printer id from a display name, unique against existing ids.
110	*
111	* @param string $name Display name.
112	* @param array<string> $existing_ids Already-used ids.
113	*
114	* @return string
115	*/
116	public static function derive_id( string $name, array $existing_ids ): string {
117	$base = sanitize_title( $name );
118	if ( '' === $base ) {
119	$base = 'printer';
120	}
121	$candidate = $base;
122	$suffix = 2;
123	while ( \in_array( $candidate, $existing_ids, true ) ) {
124	$candidate = $base . '-' . $suffix;
125	++$suffix;
126	}
127
128	return $candidate;
129	}
130
131	/**
132	* Record that a printer polled just now.
133	*
134	* @param string $printer_id Printer id.
135	*/
136	public function record_seen( string $printer_id ): void {
137	$runtime = get_option( self::RUNTIME_OPTION, array() );
138	$runtime = \is_array( $runtime ) ? $runtime : array();
139	$runtime[ $printer_id ] = time();
140	update_option( self::RUNTIME_OPTION, $runtime, false ); // Autoload no.
141	}
142
143	/**
144	* Get a printer's last-seen unix timestamp (0 if never).
145	*
146	* @param string $printer_id Printer id.
147	*
148	* @return int
149	*/
150	public function get_seen( string $printer_id ): int {
151	$runtime = get_option( self::RUNTIME_OPTION, array() );
152
153	return ( \is_array( $runtime ) && isset( $runtime[ $printer_id ] ) ) ? (int) $runtime[ $printer_id ] : 0;
154	}
155
156	/**
157	* Drop runtime last-seen entries for printer ids that no longer exist.
158	*
159	* Prevents the runtime option from growing unbounded as printers are
160	* removed, and stops a recreated id (slug reuse) from inheriting a deleted
161	* printer's stale status.
162	*
163	* @param array<string> $keep_ids Printer ids to retain.
164	*/
165	public function prune_seen( array $keep_ids ): void {
166	$runtime = get_option( self::RUNTIME_OPTION, array() );
167	if ( ! \is_array( $runtime ) ) {
168	return;
169	}
170	$pruned = array_intersect_key( $runtime, array_flip( $keep_ids ) );
171	if ( $pruned !== $runtime ) {
172	update_option( self::RUNTIME_OPTION, $pruned, false );
173	}
174	}
175
176	/**
177	* A printer's cached CloudPRNT client capabilities.
178	*
179	* Answers are returned however stale they are: a printer's decodable format
180	* list does not change while it sits on a shelf, and serving the last known
181	* answer beats falling back to "offer everything" on every cold cache. The
182	* TTL governs how often we ask again, not how long an answer is believed.
183	*
184	* @param string $printer_id Printer id.
185	*
186	* @return array{client_type:string, client_version:string, encodings:array<int, string>, status_code:string, updated:int, asked:int}
187	*/
188	public function get_capabilities( string $printer_id ): array {
189	$all = get_option( self::CAPABILITIES_OPTION, array() );
190
191	return self::hydrate( \is_array( $all ) ? ( $all[ $printer_id ] ?? array() ) : array() );
192	}
193
194	/**
195	* Normalize a stored capability entry into the full record shape.
196	*
197	* @param mixed $stored The raw stored entry, or anything at all — the option
198	* is hand-editable and predates this shape.
199	*
200	* @return array{client_type:string, client_version:string, encodings:array<int, string>, status_code:string, updated:int, asked:int}
201	*/
202	private static function hydrate( $stored ): array {
203	$stored = \is_array( $stored ) ? $stored : array();
204
205	return array(
206	'client_type' => (string) ( $stored['client_type'] ?? '' ),
207	'client_version' => (string) ( $stored['client_version'] ?? '' ),
208	'encodings' => \is_array( $stored['encodings'] ?? null ) ? array_values( array_map( 'strval', $stored['encodings'] ) ) : array(),
209	'status_code' => (string) ( $stored['status_code'] ?? '' ),
210	'updated' => (int) ( $stored['updated'] ?? 0 ),
211	'asked' => (int) ( $stored['asked'] ?? 0 ),
212	);
213	}
214
215	/**
216	* Store the answers a printer gave to our `clientAction` questions.
217	*
218	* Only the fields the printer actually answered are overwritten — a poll
219	* that carries `ClientType` but not `Encodings` must not wipe an encodings
220	* list we already know.
221	*
222	* @param string $printer_id Printer id.
223	* @param array<string, string> $answers Answers keyed by request name.
224	* @param string $status_code The printer's reported status code.
225	*
226	* @return bool Whether anything was stored. False also when a concurrent
227	* poll held the write lock; see mutate_capabilities().
228	*/
229	public function record_capabilities( string $printer_id, array $answers, string $status_code = '' ): bool {
230	return $this->mutate_printer_record(
231	$printer_id,
232	static function ( array $record ) use ( $answers, $status_code ): ?array {
233	$changed = false;
234
235	foreach ( $answers as $name => $value ) {
236	switch ( $name ) {
237	case 'ClientType':
238	$record['client_type'] = $value;
239	$changed = true;
240	break;
241	case 'ClientVersion':
242	$record['client_version'] = $value;
243	$changed = true;
244	break;
245	case 'Encodings':
246	$record['encodings'] = self::parse_encodings( $value );
247	$changed = true;
248	break;
249	}
250	}
251
252	if ( '' !== $status_code && $status_code !== $record['status_code'] ) {
253	$record['status_code'] = $status_code;
254	$changed = true;
255	}
256
257	if ( ! $changed ) {
258	return null;
259	}
260
261	$record['updated'] = time();
262
263	return $record;
264	}
265	);
266	}
267
268	/**
269	* Whether the printer should be asked for its capabilities on this poll.
270	*
271	* @param string $printer_id Printer id.
272	*
273	* @return bool
274	*/
275	public function should_request_capabilities( string $printer_id ): bool {
276	$record = $this->get_capabilities( $printer_id );
277
278	return ( time() - $record['asked'] ) >= self::CAPABILITIES_TTL;
279	}
280
281	/**
282	* Record that this poll response carried capability questions.
283	*
284	* Written even when the printer never answers, so firmware that ignores
285	* `clientAction` is asked once per TTL rather than on every poll.
286	*
287	* @param string $printer_id Printer id.
288	*/
289	public function record_capability_request( string $printer_id ): void {
290	$this->mutate_printer_record(
291	$printer_id,
292	static function ( array $record ): array {
293	$record['asked'] = time();
294
295	return $record;
296	}
297	);
298	}
299
300	/**
301	* Drop cached capabilities for printer ids that no longer exist.
302	*
303	* @param array<string> $keep_ids Printer ids to retain.
304	*/
305	public function prune_capabilities( array $keep_ids ): void {
306	$this->mutate_capabilities(
307	static function ( array $all ) use ( $keep_ids ): ?array {
308	$pruned = array_intersect_key( $all, array_flip( $keep_ids ) );
309
310	return $pruned === $all ? null : $pruned;
311	}
312	);
313	}
314
315	/**
316	* Read-modify-write one printer's capability record under the mutex.
317	*
318	* The callback receives the record as it stands inside the lock, never a
319	* snapshot taken before it. Assembling the record first and handing the
320	* finished thing to a locked setter would leave same-printer polls racing:
321	* two overlapping polls would each build from the same pre-lock read, and
322	* the second write would undo the first — restoring a stale `asked` stamp or
323	* erasing encodings that had just arrived.
324	*
325	* @param string $printer_id Printer id.
326	* @param callable $mutate Receives the current record, returns the new
327	* one, or null to write nothing.
328	*
329	* @return bool Whether the record was written.
330	*/
331	private function mutate_printer_record( string $printer_id, callable $mutate ): bool {
332	return $this->mutate_capabilities(
333	static function ( array $all ) use ( $printer_id, $mutate ): ?array {
334	$next = $mutate( self::hydrate( $all[ $printer_id ] ?? array() ) );
335	if ( null === $next ) {
336	return null;
337	}
338
339	$all[ $printer_id ] = $next;
340
341	return $all;
342	}
343	);
344	}
345
346	/**
347	* Read-modify-write the shared capabilities option under a mutex.
348	*
349	* Every registered printer polls into the same option, so an unguarded
350	* read-modify-write lets one printer's write discard another's: both read
351	* the same snapshot, each sets its own key, and the second write wins.
352	* The mutex plus a cache-bypassing read inside it makes the sequence
353	* atomic across concurrent requests.
354	*
355	* A poll that cannot take the lock skips its write rather than queueing.
356	* The record is a cache with a CAPABILITIES_TTL refresh, so the cost of a
357	* skipped write is one refresh cycle, never a wrong answer — and blocking
358	* a printer's poll to persist a cache would be the worse trade.
359	*
360	* @param callable $mutate Receives the current map, returns the new map, or
361	* null to write nothing.
362	*
363	* @return bool Whether the option was written.
364	*/
365	private function mutate_capabilities( callable $mutate ): bool {
366	if ( ! self::acquire_capabilities_lock() ) {
367	return false;
368	}
369
370	try {
371	// Drop this request's cached copy so the read reflects writes other
372	// requests made while we were waiting for the lock.
373	wp_cache_delete( self::CAPABILITIES_OPTION, 'options' );
374
375	$all = get_option( self::CAPABILITIES_OPTION, array() );
376	$all = \is_array( $all ) ? $all : array();
377
378	$next = $mutate( $all );
379	if ( null === $next ) {
380	return false;
381	}
382
383	update_option( self::CAPABILITIES_OPTION, $next, false ); // Autoload no.
384	} finally {
385	delete_option( self::CAPABILITIES_LOCK );
386	}
387
388	return true;
389	}
390
391	/**
392	* Take the capabilities mutex.
393	*
394	* The atomic primitive is add_option(): the options table's unique index on
395	* option_name means exactly one concurrent caller can create the row. This
396	* mirrors Print_Job_Service's lifecycle lock.
397	*
398	* @return bool Whether the lock was taken.
399	*/
400	private static function acquire_capabilities_lock(): bool {
401	$now = time();
402
403	if ( add_option( self::CAPABILITIES_LOCK, (string) $now, '', false ) ) {
404	return true;
405	}
406
407	$locked_at = (int) get_option( self::CAPABILITIES_LOCK, 0 );
408	if ( $locked_at > 0 && ( $now - $locked_at ) > self::CAPABILITIES_LOCK_TTL ) {
409	delete_option( self::CAPABILITIES_LOCK );
410
411	return add_option( self::CAPABILITIES_LOCK, (string) $now, '', false );
412	}
413
414	return false;
415	}
416
417	/**
418	* Read a printer's `Encodings` answer into a list of media types.
419	*
420	* The answer is a delimited string of the media types the client can decode
421	* (Star's own plugin substring-matches it). Splitting on both `,` and `;`
422	* and then keeping only `type/subtype` tokens drops MIME parameters such as
423	* `charset=utf-8` without needing to know which delimiter the firmware used.
424	*
425	* @param string $value The raw `Encodings` answer.
426	*
427	* @return array<int, string> Lower-cased media types, in the printer's order.
428	*/
429	private static function parse_encodings( string $value ): array {
430	$tokens = preg_split( '/[,;\r\n\t ]+/', strtolower( $value ) );
431	if ( false === $tokens ) {
432	return array();
433	}
434
435	$types = array();
436	foreach ( $tokens as $token ) {
437	$token = trim( $token );
438	if ( 1 === preg_match( '#^[a-z0-9][a-z0-9!\#$&^_.+-]/[a-z0-9][a-z0-9!\#$&^_.+-]$#', $token ) ) {
439	$types[] = $token;
440	}
441	}
442
443	return array_values( array_unique( $types ) );
444	}
445
446	/**
447	* Connection status for a printer.
448	*
449	* For PrintNode printers this returns PrintNode's live vocabulary
450	* ('online'\|'offline'\|'unknown'), cached briefly. For polling printers
451	* (Star/Epson) it returns 'waiting' (never polled), 'connected' (polled
452	* within SEEN_TTL), or 'offline' (polled, but stale).
453	*
454	* @param string $printer_id Printer id.
455	*
456	* @return string
457	*/
458	public function status_for( string $printer_id ): string {
459	$printer = $this->get_printer( $printer_id );
460	if ( null !== $printer ) {
461	$provider = Provider::normalize( \is_string( $printer['provider'] ?? null ) ? $printer['provider'] : null );
462	$adapter = Provider::adapter( $provider );
463	if ( null !== $adapter ) {
464	return $adapter->status(
465	$printer,
466	array(
467	'now' => time(),
468	'seen' => $this->get_seen( $printer_id ),
469	'seen_ttl' => self::SEEN_TTL,
470	'cache_ttl' => self::PN_STATUS_TTL,
471	'relay_status' => Provider::is_polling( $provider ) ? Cloud_Print_Relay_Service::status( $printer_id ) : null,
472	)
473	);
474	}
475	}
476
477	/*
478	* Shared fallthrough, kept from the pre-adapter implementation: a
479	* printer_id with a recorded poll but no registry row — or a row whose
480	* provider is unrecognised — is still reported from its last-seen
481	* timestamp, not as 'waiting'. Returning early here instead reported a
482	* recently-polled printer as never-seen.
483	* `test_status_connected_when_recently_seen` pins this.
484	*/
485	$seen = $this->get_seen( $printer_id );
486	if ( 0 === $seen ) {
487	return 'waiting';
488	}
489
490	return ( time() - $seen ) <= self::SEEN_TTL ? 'connected' : 'offline';
491	}
492
493	/**
494	* The relay's block signal for a printer, when it reports one.
495	*
496	* Delegates to the relay service's transient-cached status, so this is
497	* safe to call in any order relative to status_for().
498	*
499	* @param string $printer_id Printer ID.
500	*
501	* @return string\|null
502	*/
503	public function status_detail_for( string $printer_id ): ?string {
504	return Cloud_Print_Relay_Service::status_detail( $printer_id );
505	}
506	}
507