xspeed / includes / class-redis-client.php

class-redis-client.php in xSpeed Cache: AI-Powered Performance Hub with MCP, Caching & CDN 1.0.4, at includes/class-redis-client.php

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1	<?php
2	/**
3	* XSpeed_Redis_Client — a minimal, dependency-free Redis client.
4	*
5	* Speaks the Redis wire protocol (RESP) directly over a TCP socket. It exists
6	* so xSpeed's object cache can talk to Redis WITHOUT the phpredis extension and
7	* WITHOUT bundling a heavyweight library (Predis ships 700+ files for cluster /
8	* sentinel / pub-sub / transactions we never use). This implements exactly the
9	* commands the object cache needs and nothing more:
10	*
11	* AUTH, SELECT, PING, GET, SET, SETEX, DEL, INCRBY, DECRBY, FLUSHDB
12	*
13	* It is intentionally NOT a general-purpose client. Every method maps to one
14	* Redis command. Errors never throw past connect(); read/write failures return
15	* false so the object cache degrades gracefully instead of fataling the site.
16	*
17	* RESP reference: https://redis.io/docs/reference/protocol-spec/
18	*
19	* @package XSpeed
20	*/
21
22	declare(strict_types=1);
23
24	namespace XSpeed;
25
26	defined( 'ABSPATH' ) \|\| exit;
27
28	class Redis_Client {
29
30	/** @var resource\|null Socket handle. */
31	private $sock = null;
32
33	/** @var string */
34	private $host;
35
36	/** @var int */
37	private $port;
38
39	/** @var float */
40	private $timeout;
41
42	/** @var bool Persistent connection (pconnect-style). */
43	private $persistent;
44
45	public function __construct( string $host = '127.0.0.1', int $port = 6379, float $timeout = 1.0, bool $persistent = false ) {
46	$this->host = $host;
47	$this->port = $port;
48	$this->timeout = $timeout > 0 ? $timeout : 1.0;
49	$this->persistent = $persistent;
50	}
51
52	/**
53	* Open the socket. Returns true on success. Never throws — callers check
54	* the boolean and fall back to a non-persistent cache on failure.
55	*/
56	public function connect(): bool {
57	$flags = STREAM_CLIENT_CONNECT \| ( $this->persistent ? STREAM_CLIENT_PERSISTENT : 0 );
58	$errno = 0;
59	$errstr = '';
60	// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fopen, WordPress.PHP.NoSilencedErrors.Discouraged -- A raw stream socket is the only way to speak the Redis protocol; WP_Filesystem cannot open TCP sockets. Errors are captured via $errno/$errstr and surfaced as a boolean.
61	$sock = @stream_socket_client(
62	"tcp://{$this->host}:{$this->port}",
63	$errno,
64	$errstr,
65	$this->timeout,
66	$flags
67	);
68	if ( ! $sock ) {
69	return false;
70	}
71	stream_set_timeout( $sock, (int) $this->timeout, (int) ( ( $this->timeout - (int) $this->timeout ) * 1000000 ) );
72	$this->sock = $sock;
73	return true;
74	}
75
76	public function is_connected(): bool {
77	return is_resource( $this->sock );
78	}
79
80	// --- Commands -----------------------------------------------------------
81
82	public function auth( string $password ) {
83	return $this->command( array( 'AUTH', $password ) );
84	}
85
86	public function select( int $db ) {
87	return $this->command( array( 'SELECT', (string) $db ) );
88	}
89
90	/** @return string\|bool '+PONG' on success, false on failure. */
91	public function ping() {
92	$r = $this->command( array( 'PING' ) );
93	return ( null === $r \|\| false === $r ) ? false : $r;
94	}
95
96	/** @return string\|false The value, or false if the key is missing. */
97	public function get( string $key ) {
98	$r = $this->command( array( 'GET', $key ) );
99	return null === $r ? false : $r;
100	}
101
102	public function set( string $key, string $value ): bool {
103	$r = $this->command( array( 'SET', $key, $value ) );
104	return '+OK' === $r \|\| 'OK' === $r;
105	}
106
107	public function setex( string $key, int $ttl, string $value ): bool {
108	$r = $this->command( array( 'SETEX', $key, (string) $ttl, $value ) );
109	return '+OK' === $r \|\| 'OK' === $r;
110	}
111
112	/**
113	* Atomic add — SET ... NX, which stores only if the key does NOT exist.
114	* Returns true when stored, false when the key already existed (Redis
115	* replies nil → null here) or on error. With $ttl > 0 the EX option makes
116	* the store + expiry atomic. Used by the drop-in's wp_cache_add so add()
117	* honours its "fail if the key is present" contract across requests, not
118	* just the per-request runtime cache. (FBS-82111 Bug 2)
119	*/
120	public function add( string $key, string $value, int $ttl = 0 ): bool {
121	$args = array( 'SET', $key, $value, 'NX' );
122	if ( $ttl > 0 ) {
123	$args[] = 'EX';
124	$args[] = (string) $ttl;
125	}
126	$r = $this->command( $args );
127	return '+OK' === $r \|\| 'OK' === $r;
128	}
129
130	/** @return int Number of keys removed. */
131	public function del( string $key ): int {
132	return (int) $this->command( array( 'DEL', $key ) );
133	}
134
135	/** @return int\|false New value, or false on error. */
136	public function incrBy( string $key, int $offset ) {
137	return $this->command( array( 'INCRBY', $key, (string) $offset ) );
138	}
139
140	/** @return int\|false New value, or false on error. */
141	public function decrBy( string $key, int $offset ) {
142	return $this->command( array( 'DECRBY', $key, (string) $offset ) );
143	}
144
145	public function flushDB(): bool {
146	$r = $this->command( array( 'FLUSHDB' ) );
147	return '+OK' === $r \|\| 'OK' === $r;
148	}
149
150	public function close(): void {
151	if ( is_resource( $this->sock ) && ! $this->persistent ) {
152	// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose -- Closing a raw TCP socket opened with stream_socket_client; not a WP_Filesystem-managed handle.
153	@fclose( $this->sock ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- best-effort close on shutdown.
154	}
155	$this->sock = null;
156	}
157
158	// --- RESP protocol ------------------------------------------------------
159
160	/**
161	* Encode a command as a RESP array of bulk strings, write it, read one
162	* reply. Returns the decoded reply, or false on any socket error.
163	*
164	* @param string[] $args
165	* @return mixed
166	*/
167	private function command( array $args ) {
168	if ( ! is_resource( $this->sock ) ) {
169	return false;
170	}
171
172	$payload = '*' . count( $args ) . "\r\n";
173	foreach ( $args as $a ) {
174	$a = (string) $a;
175	$payload .= '$' . strlen( $a ) . "\r\n" . $a . "\r\n";
176	}
177
178	// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fwrite, WordPress.PHP.NoSilencedErrors.Discouraged -- Writing to the Redis TCP socket; WP_Filesystem has no socket transport. Failure returns false and the cache degrades.
179	if ( false === @fwrite( $this->sock, $payload ) ) {
180	$this->sock = null;
181	return false;
182	}
183
184	return $this->read_reply();
185	}
186
187	/**
188	* Read and decode a single RESP reply from the socket.
189	*
190	* @return mixed string\|int\|null\|array\|false
191	*/
192	private function read_reply() {
193	$line = $this->read_line();
194	if ( false === $line \|\| '' === $line ) {
195	return false;
196	}
197
198	$type = $line[0];
199	$body = substr( $line, 1 );
200
201	switch ( $type ) {
202	case '+': // Simple string.
203	return $body;
204	case '-': // Error.
205	return false;
206	case ':': // Integer.
207	return (int) $body;
208	case '$': // Bulk string.
209	$len = (int) $body;
210	if ( $len < 0 ) {
211	return null; // Null bulk = key missing.
212	}
213	$data = $this->read_bytes( $len + 2 ); // +2 for trailing CRLF.
214	return false === $data ? false : substr( $data, 0, $len );
215	case '*': // Array.
216	$count = (int) $body;
217	if ( $count < 0 ) {
218	return null;
219	}
220	$out = array();
221	for ( $i = 0; $i < $count; $i++ ) {
222	$out[] = $this->read_reply();
223	}
224	return $out;
225	default:
226	return false;
227	}
228	}
229
230	/** Read one CRLF-terminated line (without the CRLF). */
231	private function read_line() {
232	if ( ! is_resource( $this->sock ) ) {
233	return false;
234	}
235	// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fgets, WordPress.PHP.NoSilencedErrors.Discouraged -- Reading a line from the Redis TCP socket.
236	$line = @fgets( $this->sock );
237	if ( false === $line ) {
238	return false;
239	}
240	return rtrim( $line, "\r\n" );
241	}
242
243	/** Read exactly $n bytes from the socket. */
244	private function read_bytes( int $n ) {
245	if ( ! is_resource( $this->sock ) ) {
246	return false;
247	}
248	$buf = '';
249	while ( strlen( $buf ) < $n ) {
250	// phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fread, WordPress.PHP.NoSilencedErrors.Discouraged -- Reading the bulk-string body from the Redis TCP socket.
251	$chunk = @fread( $this->sock, $n - strlen( $buf ) );
252	if ( false === $chunk \|\| '' === $chunk ) {
253	$meta = stream_get_meta_data( $this->sock );
254	if ( ! empty( $meta['timed_out'] ) ) {
255	return false;
256	}
257	break;
258	}
259	$buf .= $chunk;
260	}
261	return $buf;
262	}
263	}
264