404-solution / includes / diagnostics / HostServerCounterProbe.php

HostServerCounterProbe.php in 404 Solution trunk, at includes/diagnostics/HostServerCounterProbe.php

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1	<?php
2
3	if (!defined('ABSPATH')) {
4	exit;
5	}
6
7	/**
8	* Reads provider admission counters exposed to the PHP worker environment.
9	*
10	* Both PHP server variables and the process environment are checked because
11	* LSAPI deployments do not consistently populate the same boundary. A miss
12	* preserves the result of each source instead of collapsing it to an empty
13	* array that could be mistaken for a healthy zero.
14	*/
15	final class ABJ_404_Solution_HostServerCounterProbe {
16
17	/**
18	* @param array<string, mixed> $environment
19	* @return array<string, mixed>
20	*/
21	public static function capture(string $pattern, array $environment): array {
22	$sources = array('$_SERVER' => $_SERVER);
23	if (($environment['status'] ?? '') === 'available'
24	&& is_array($environment['values'] ?? null)) {
25	$sources['getenv()'] = $environment['values'];
26	}
27
28	$values = array();
29	$attemptedPaths = array();
30	$matched = false;
31	foreach ($sources as $sourceName => $source) {
32	$scan = self::scanSource($pattern, $source);
33	$values += $scan['values'];
34	$attemptedPaths[$sourceName] = $scan['outcome'];
35	$matched = $matched \|\| $scan['matched'];
36	}
37	if (!array_key_exists('getenv()', $attemptedPaths)) {
38	$attemptedPaths['getenv()'] = self::environmentOutcome($environment);
39	}
40
41	ksort($values);
42	if ($values !== array()) {
43	return array('status' => 'available', 'values' => $values);
44	}
45	$reason = self::unavailableReason($environment, $matched);
46	return array(
47	'status' => 'unavailable',
48	'reason' => $reason,
49	'attempted_paths' => $attemptedPaths,
50	'context' => array('php_sapi_name' => php_sapi_name()),
51	);
52	}
53
54	/**
55	* @param array<mixed> $source
56	* @return array{values: array<string, string>, outcome: string, matched: bool}
57	*/
58	private static function scanSource(string $pattern, array $source): array {
59	$values = array();
60	$matched = false;
61	foreach ($source as $key => $value) {
62	if (!is_string($key) \|\| preg_match($pattern, $key) !== 1) {
63	continue;
64	}
65	$matched = true;
66	$readable = self::readableScalar($value, 64);
67	if ($readable !== null) {
68	$values[$key] = $readable;
69	}
70	}
71	$outcome = !$matched
72	? 'no_matching_variables'
73	: ($values === array() ? 'no_readable_counters' : 'readable_counter_found');
74	return array('values' => $values, 'outcome' => $outcome, 'matched' => $matched);
75	}
76
77	/** @param array<string, mixed> $environment */
78	private static function environmentOutcome(array $environment): string {
79	$reason = $environment['reason'] ?? 'environment_unavailable';
80	return is_scalar($reason) ? (string)$reason : 'environment_unavailable';
81	}
82
83	/** @param array<string, mixed> $environment */
84	private static function unavailableReason(array $environment, bool $matched): string {
85	if ($matched) {
86	return 'no_readable_counters';
87	}
88	if (($environment['status'] ?? '') === 'available') {
89	return 'no_matching_variables';
90	}
91	$reason = $environment['reason'] ?? null;
92	return is_string($reason) && $reason !== '' ? $reason : 'environment_unavailable';
93	}
94
95	/** @param mixed $value */
96	private static function readableScalar($value, int $maxLength): ?string {
97	if (!is_scalar($value)) {
98	return null;
99	}
100	$string = is_bool($value) ? ($value ? '1' : '0') : (string)$value;
101	$ascii = preg_replace('/[^\x20-\x7E]/', '?', $string);
102	if (!is_string($ascii)) {
103	return null;
104	}
105	$truncated = substr($ascii, 0, $maxLength);
106	return is_string($truncated) ? $truncated : null;
107	}
108	}
109