mlsimport / includes / live / live-cache.php

live-cache.php in MLSImport: IDX Plugin & MLS Plugin for Real Estate Listings 7.1.2, at includes/live/live-cache.php

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1	<?php
2	/**
3	* Live mode: transient cache for direct MLS reads.
4	*
5	* One idiom: mlsimport_live_remember( $key, $fetch ). Each entry stores its
6	* payload plus a freshness deadline inside a transient that lives a full day,
7	* so an MLS outage serves warm-stale data instead of an empty page. Keys hash
8	* the normalized request (sorted params, floats rounded) so map pans and
9	* equivalent filter orders reuse entries. Cleanup rides WP's daily
10	* expired-transient purge; "Clear live cache" bumps a generation salt so
11	* every keyed entry is retired at once — no options scan, no object-cache
12	* flush (which would evict unrelated site cache on persistent backends).
13	*
14	* @package Mlsimport
15	*/
16
17	if ( ! defined( 'ABSPATH' ) ) {
18	exit;
19	}
20
21	/**
22	* Build a cache key from a normalized request description.
23	*
24	* @param string $group Short group tag (search, get, …).
25	* @param array $parts Request-defining values (params + config essentials).
26	* @return string
27	*/
28	function mlsimport_live_cache_key( string $group, array $parts ): string {
29	// Group tag + md5 of (generation salt \| normalized request). The salt makes
30	// a cache-clear retire every key; normalization makes equivalent requests
31	// collapse to one key.
32	return 'mlsimport_live_' . $group . '_' . md5(
33	mlsimport_live_cache_version() . '\|' . (string) wp_json_encode( mlsimport_live_cache_normalize( $parts ) )
34	);
35	}
36
37	/**
38	* The cache generation salt baked into every keyed entry. Bumping it retires
39	* all keyed entries at once; the orphaned rows expire with their day TTL.
40	*
41	* @return int
42	*/
43	function mlsimport_live_cache_version(): int {
44	// Read the salt option; floor at 1 so a missing/zeroed option is still valid.
45	return max( 1, (int) get_option( 'mlsimport_live_cache_version', 1 ) );
46	}
47
48	/**
49	* Normalize request values for stable cache keys: recursive key sort and
50	* floats rounded to 3 decimals (~110m) so tiny map-pan deltas share entries.
51	*
52	* @param array $parts Request values.
53	* @return array
54	*/
55	function mlsimport_live_cache_normalize( array $parts ): array {
56	$out = array();
57	// Walk every value, normalizing in place.
58	foreach ( $parts as $key => $value ) {
59	if ( is_array( $value ) ) {
60	// Nested arrays (e.g. multi-value filters): recurse.
61	$out[ $key ] = mlsimport_live_cache_normalize( $value );
62	} elseif ( is_float( $value ) \|\| ( is_string( $value ) && is_numeric( $value ) && false !== strpos( $value, '.' ) ) ) {
63	// A real float, or a numeric string carrying a decimal point (map
64	// coords arrive as strings): round to 3dp so tiny pan deltas match.
65	$out[ $key ] = round( (float) $value, 3 );
66	} else {
67	// Ints, bools, plain strings: keep verbatim.
68	$out[ $key ] = $value;
69	}
70	}
71	// Sort by key so param order never changes the resulting key.
72	ksort( $out );
73	return $out;
74	}
75
76	/**
77	* Return the cached value for $key, refreshing it via $fetch when stale.
78	*
79	* $fetch returning null means "the source failed" — the stale payload (when
80	* one exists) is served instead and retried on the next request.
81	*
82	* @param string $key Cache key from mlsimport_live_cache_key().
83	* @param callable $fetch Returns the fresh value, or null on failure.
84	* @return mixed Null only when there is no fresh value and no stale copy.
85	*/
86	function mlsimport_live_remember( string $key, callable $fetch ) {
87	// Load any existing entry and pin "now" for the freshness comparison.
88	$entry = get_transient( $key );
89	$now = time();
90
91	// Fresh hit: a well-formed entry still inside its freshness window — return
92	// the payload without touching the source.
93	if ( is_array( $entry ) && array_key_exists( 'data', $entry ) && isset( $entry['fresh_until'] ) && $entry['fresh_until'] >= $now ) {
94	return $entry['data'];
95	}
96
97	// Miss or stale: go to the source.
98	$fresh = $fetch();
99	if ( null !== $fresh ) {
100	// Success: store payload + a fresh-until deadline, but let the whole
101	// row live a full day so it can still be served warm-stale after.
102	set_transient(
103	$key,
104	array(
105	'data' => $fresh,
106	'fresh_until' => $now + mlsimport_live_cache_ttl(),
107	),
108	DAY_IN_SECONDS
109	);
110	return $fresh;
111	}
112
113	// Source failed: serve warm-stale when we have it.
114	if ( is_array( $entry ) && array_key_exists( 'data', $entry ) ) {
115	return $entry['data'];
116	}
117
118	// No fresh value and no stale copy: the caller gets nothing.
119	return null;
120	}
121
122	/**
123	* Retire every live-mode cache entry (the settings screen button).
124	*
125	* Keyed entries are invalidated by bumping the generation salt. The handful
126	* of fixed-name transients (the entitlement flag, price ceiling, provider
127	* tokens) are deleted directly — the API also evicts them from persistent
128	* object caches.
129	*
130	* @return void
131	*/
132	function mlsimport_live_cache_clear(): void {
133	// Bump the generation salt: every keyed entry now hashes to a new key and
134	// is effectively retired (the orphans expire with their day TTL).
135	update_option( 'mlsimport_live_cache_version', mlsimport_live_cache_version() + 1 );
136
137	// Fixed-name shared transients aren't keyed by the salt, so delete them by
138	// hand. The Provider Family module owns the provider-token list.
139	$fixed = array( 'mlsimport_live_entitlement_checked', 'mlsimport_live_price_ceiling' );
140	// Delete each — this also evicts it from a persistent object cache.
141	foreach ( $fixed as $name ) {
142	delete_transient( $name );
143	}
144	Mlsimport_Provider_Family::clear_direct_access_tokens();
145	}
146