xspeed / includes / class-cache-benchmark.php

class-cache-benchmark.php in xSpeed Cache: AI-Powered Performance Hub with MCP, Caching & CDN 1.3.0, at includes/class-cache-benchmark.php

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1	<?php
2	/**
3	* Cache_Benchmark — fetches home_url() twice (with + without cache) and
4	* returns side-by-side TTFB / total-time / transfer-bytes timings.
5	*
6	* Powers the "before vs after cache" widget on the wizard's Done step
7	* and the Cache panel. Synthetic — measures local HTTP only, no real
8	* RUM. Good enough for a directional "cache helps by X%" number; the
9	* RUM module is what you want for real percentiles.
10	*
11	* Mechanics:
12	* - "Without cache": HTTP GET home_url() with header
13	* `X-XSpeed-Bypass: 1`. The advanced-cache drop-in honors this
14	* header and short-circuits, so WordPress fully renders.
15	* - "With cache": HTTP GET home_url() with no special header. The
16	* drop-in serves the cached file (cache HIT) when available.
17	* - First "with-cache" call may MISS if no entry yet — we run a
18	* warm-up hit first so the timed pair is HIT vs render.
19	*
20	* Each measurement records:
21	* ttfb_ms — curl_getinfo CURLINFO_STARTTRANSFER_TIME (or our
22	* own "time before body read" fallback).
23	* time_ms — total response time.
24	* bytes — DECODED payload size (what the browser parses).
25	* bytes_transferred — wire size: the request advertises
26	* `Accept-Encoding: gzip, deflate` with WP auto-
27	* decompression off, so this is what actually
28	* crossed the network (matches GTmetrix's
29	* "transferred" number, not the inflated one).
30	* status — HTTP code.
31	*
32	* @package XSpeed
33	*/
34
35	declare(strict_types=1);
36
37	namespace XSpeed;
38
39	defined( 'ABSPATH' ) \|\| exit;
40
41	final class Cache_Benchmark {
42
43	/** Benchmark run history (option, autoload off): newest LAST. */
44	public const HISTORY_OPT = 'xspeed_benchmark_history';
45
46	/** Runs retained — enough for a year of weekly runs with headroom. */
47	public const HISTORY_MAX = 100;
48
49	/**
50	* @return array{
51	* url:string,
52	* without_cache:array{ttfb_ms:float,time_ms:float,bytes:int,bytes_transferred:int,status:int},
53	* with_cache:array{ttfb_ms:float,time_ms:float,bytes:int,bytes_transferred:int,status:int,was_hit:bool},
54	* savings_pct:?float,
55	* savings_ms:?float,
56	* cache_enabled:bool,
57	* }
58	*/
59	public static function run( ?string $url = null ): array {
60	if ( null === $url ) {
61	$url = home_url( '/' );
62	}
63	// Cache enablement lives on the legacy Settings option
64	// (`cache_enabled` boolean). Cache::is_enabled() doesn't
65	// exist — read through Settings::get() instead.
66	$cache_enabled = false;
67	if ( class_exists( '\\XSpeed\\Settings' ) ) {
68	$opts = Settings::get();
69	$cache_enabled = ! empty( $opts['cache_enabled'] );
70	}
71
72	// Warm up so the "with cache" timing reflects a HIT, not the
73	// initial generation cost.
74	if ( $cache_enabled ) {
75	self::measure( $url, false );
76	}
77
78	$without = self::measure( $url, true ); // bypass
79	$with = self::measure( $url, false ); // normal — should HIT
80
81	$savings_ms = null;
82	$savings_pct = null;
83	if ( $cache_enabled && $without['time_ms'] > 0 && $with['time_ms'] > 0 ) {
84	$diff = $without['time_ms'] - $with['time_ms'];
85	$savings_ms = max( 0.0, round( $diff, 1 ) );
86	$savings_pct = round( ( $diff / $without['time_ms'] ) * 100, 1 );
87	if ( $savings_pct < 0 ) {
88	$savings_pct = 0.0;
89	}
90	}
91
92	$result = array(
93	'url' => $url,
94	'without_cache' => $without,
95	'with_cache' => $with + array( 'was_hit' => $cache_enabled ),
96	'savings_pct' => $savings_pct,
97	'savings_ms' => $savings_ms,
98	'cache_enabled' => $cache_enabled,
99	);
100
101	self::record_run( $result );
102
103	return $result;
104	}
105
106	/**
107	* Persist a run into the history ring buffer (issue #43) so the
108	* dashboard can render a trend instead of a one-shot number. Failed
109	* fetches (status 0) are not recorded — a network blip isn't a data
110	* point about the site's performance.
111	*
112	* @param array $result The array shape run() returns.
113	*/
114	public static function record_run( array $result ): void {
115	$without = isset( $result['without_cache'] ) && is_array( $result['without_cache'] ) ? $result['without_cache'] : array();
116	$with = isset( $result['with_cache'] ) && is_array( $result['with_cache'] ) ? $result['with_cache'] : array();
117	if ( (int) ( $without['status'] ?? 0 ) === 0 \|\| (int) ( $with['status'] ?? 0 ) === 0 ) {
118	return;
119	}
120	$history = get_option( self::HISTORY_OPT, array() );
121	if ( ! is_array( $history ) ) {
122	$history = array();
123	}
124	$history[] = array(
125	'ts' => time(),
126	'uncached_ms' => (float) ( $without['time_ms'] ?? 0 ),
127	'cached_ms' => (float) ( $with['time_ms'] ?? 0 ),
128	'savings_ms' => isset( $result['savings_ms'] ) ? (float) $result['savings_ms'] : null,
129	'savings_pct' => isset( $result['savings_pct'] ) ? (float) $result['savings_pct'] : null,
130	'bytes' => (int) ( $with['bytes'] ?? 0 ),
131	'bytes_transferred' => (int) ( $with['bytes_transferred'] ?? 0 ),
132	'cache_enabled' => ! empty( $result['cache_enabled'] ),
133	);
134	if ( count( $history ) > self::HISTORY_MAX ) {
135	$history = array_slice( $history, -self::HISTORY_MAX );
136	}
137	update_option( self::HISTORY_OPT, $history, false );
138	}
139
140	/**
141	* Stored benchmark runs, oldest→newest, at most $limit rows.
142	*
143	* @return array<int,array<string,mixed>>
144	*/
145	public static function history( int $limit = self::HISTORY_MAX ): array {
146	$history = get_option( self::HISTORY_OPT, array() );
147	if ( ! is_array( $history ) ) {
148	return array();
149	}
150	return array_slice( array_values( $history ), -max( 1, $limit ) );
151	}
152
153	/**
154	* Single timed request. wp_remote_get's `args` don't expose curl-
155	* level timing on every transport, so we wrap the call ourselves
156	* with microtime — close enough for a directional comparison.
157	*
158	* @return array{ttfb_ms:float,time_ms:float,bytes:int,bytes_transferred:int,status:int}
159	*/
160	private static function measure( string $url, bool $bypass ): array {
161	$headers = array(
162	'User-Agent' => 'xSpeed Benchmark/1.0',
163	// Ask for compression like a real browser so the WIRE size is
164	// measurable. Only encodings we can decode locally — no brotli
165	// (ext-brotli is rare, and an undecodable body would break the
166	// uncompressed measurement).
167	'Accept-Encoding' => 'gzip, deflate',
168	);
169	if ( $bypass ) {
170	// The X-XSpeed-Bypass header only short-circuits the PHP
171	// drop-in. When nginx static-rewrite is firing it would
172	// still serve the cached file directly, so the "without
173	// cache" measurement would look identical to "with cache"
174	// (the bug visible on the dashboard's benchmark widget).
175	// Append a cache-buster query string so the nginx
176	// snippet's `if ($args)` check bails too, forcing the
177	// request all the way through to PHP.
178	$headers['X-XSpeed-Bypass'] = '1';
179	$bust_url = $url . ( false === strpos( $url, '?' ) ? '?' : '&' )
180	. 'xspeed_bypass=' . wp_generate_password( 12, false, false );
181	$url = $bust_url;
182	}
183	$start = microtime( true );
184	$res = wp_remote_get(
185	$url,
186	array(
187	'timeout' => 10,
188	'headers' => $headers,
189	// Disable WP's internal caching layer — every call MUST hit the network.
190	'reject_unsafe_urls' => false,
191	'sslverify' => false, // self-signed sandboxes
192	// Keep the body EXACTLY as it came off the wire. WP's
193	// transport otherwise auto-decompresses AND strips the
194	// Content-Encoding header, which is how the old code ended
195	// up reporting ~180KB for a page that transfers 35KB.
196	'decompress' => false,
197	)
198	);
199	$elapsed = ( microtime( true ) - $start ) * 1000.0;
200
201	if ( is_wp_error( $res ) ) {
202	return array(
203	'ttfb_ms' => 0.0,
204	'time_ms' => round( $elapsed, 1 ),
205	'bytes' => 0,
206	'bytes_transferred' => 0,
207	'status' => 0,
208	);
209	}
210	$status = (int) wp_remote_retrieve_response_code( $res );
211	$body = wp_remote_retrieve_body( $res );
212	$raw = is_string( $body ) ? $body : '';
213
214	// Wire size vs decoded size. `bytes` keeps its historical meaning
215	// (uncompressed payload) so existing consumers don't shift; the new
216	// `bytes_transferred` is what actually crossed the network.
217	$encoding = (string) wp_remote_retrieve_header( $res, 'content-encoding' );
218	$decoded = self::decode_body( $raw, $encoding );
219
220	// wp_remote_get doesn't surface TTFB separately on the default
221	// transport. We surface total time as both fields and let the
222	// widget pick a sensible display.
223	return array(
224	'ttfb_ms' => round( $elapsed, 1 ),
225	'time_ms' => round( $elapsed, 1 ),
226	'bytes' => strlen( null !== $decoded ? $decoded : $raw ),
227	'bytes_transferred' => strlen( $raw ),
228	'status' => $status,
229	);
230	}
231
232	/**
233	* Decode a response body per its Content-Encoding. Pure — unit-tested.
234	*
235	* @param string $body Raw (possibly compressed) body.
236	* @param string $encoding Content-Encoding header value ('' when none).
237	* @return string\|null Decoded body, the input when identity/none, or
238	* null when the encoding is unknown/undecodable.
239	*/
240	public static function decode_body( string $body, string $encoding ): ?string {
241	$encoding = strtolower( trim( $encoding ) );
242	if ( '' === $encoding \|\| 'identity' === $encoding ) {
243	return $body;
244	}
245	if ( '' === $body ) {
246	return $body;
247	}
248	if ( false !== strpos( $encoding, 'gzip' ) && function_exists( 'gzdecode' ) ) {
249	$out = @gzdecode( $body ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- corrupt stream must degrade to null, not warn.
250	return is_string( $out ) ? $out : null;
251	}
252	if ( false !== strpos( $encoding, 'deflate' ) && function_exists( 'gzinflate' ) ) {
253	// Some servers send zlib-wrapped deflate; try raw first, then zlib.
254	$out = @gzinflate( $body ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- see above.
255	if ( ! is_string( $out ) && function_exists( 'gzuncompress' ) ) {
256	$out = @gzuncompress( $body ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- see above.
257	}
258	return is_string( $out ) ? $out : null;
259	}
260	return null;
261	}
262	}
263