File: ParamValidator.php

package info (click to toggle)
mediawiki 1%3A1.43.3%2Bdfsg-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 417,464 kB
  • sloc: php: 1,062,949; javascript: 664,290; sql: 9,714; python: 5,458; xml: 3,489; sh: 1,131; makefile: 64
file content (897 lines) | stat: -rw-r--r-- 30,620 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
<?php

namespace Wikimedia\ParamValidator;

use DomainException;
use InvalidArgumentException;
use Wikimedia\Assert\Assert;
use Wikimedia\Message\DataMessageValue;
use Wikimedia\Message\MessageValue;
use Wikimedia\Message\ParamType;
use Wikimedia\Message\ScalarParam;
use Wikimedia\ObjectFactory\ObjectFactory;

/**
 * Service for formatting and validating API parameters
 *
 * A settings array is simply an array with keys being the relevant PARAM_*
 * constants from this class, TypeDef, and its subclasses.
 *
 * As a general overview of the architecture here:
 *  - ParamValidator handles some general validation of the parameter,
 *    then hands off to a TypeDef subclass to validate the specific representation
 *    based on the parameter's type.
 *  - TypeDef subclasses handle conversion between the string representation
 *    submitted by the client and the output PHP data types, validating that the
 *    strings are valid representations of the intended type as they do so.
 *  - ValidationException is used to report fatal errors in the validation back
 *    to the caller, since the return value represents the successful result of
 *    the validation and might be any type or class.
 *  - The Callbacks interface allows ParamValidator to reach out and fetch data
 *    it needs to perform the validation. Currently that includes:
 *    - Fetching the value of the parameter being validated (largely since a generic
 *      caller cannot know whether it needs to fetch a string from $_GET/$_POST or
 *      an array from $_FILES).
 *    - Reporting of non-fatal warnings back to the caller.
 *    - Fetching the "high limits" flag when necessary, to avoid the need for loading
 *      the user unnecessarily.
 *
 * @since 1.34
 * @unstable
 */
class ParamValidator {

	// region    Constants for parameter settings arrays
	/** @name    Constants for parameter settings arrays
	 * These constants are keys in the settings array that define how the
	 * parameters coming in from the request are to be interpreted.
	 *
	 * If a constant is associated with a failure code, the failure code
	 * and data are described. ValidationExceptions are typically thrown, but
	 * those indicated as "non-fatal" are instead passed to
	 * Callbacks::recordCondition().
	 *
	 * Additional constants may be defined by TypeDef subclasses, or by other
	 * libraries for controlling things like auto-generated parameter documentation.
	 * For purposes of namespacing the constants, the values of all constants
	 * defined by this library begin with 'param-'.
	 *
	 * @{
	 */

	/**
	 * (mixed) Default value of the parameter. If omitted, null is the default.
	 *
	 * TypeDef::validate() will be informed when the default value was used by the presence of
	 * 'is-default' in $options.
	 */
	public const PARAM_DEFAULT = 'param-default';

	/**
	 * (string|array) Type of the parameter.
	 * Must be a registered type or an array of enumerated values (in which case the "enum"
	 * type must be registered). If omitted, the default is the PHP type of the default value
	 * (see PARAM_DEFAULT).
	 */
	public const PARAM_TYPE = 'param-type';

	/**
	 * (bool) Indicate that the parameter is required.
	 *
	 * Failure codes:
	 *  - 'missingparam': The parameter is omitted/empty (and no default was set). No data.
	 */
	public const PARAM_REQUIRED = 'param-required';

	/**
	 * (bool) Indicate that the parameter is multi-valued.
	 *
	 * A multi-valued parameter may be submitted in one of several formats. All
	 * of the following result in a value of `[ 'a', 'b', 'c' ]`.
	 *  - "a|b|c", i.e. pipe-separated.
	 *  - "\x1Fa\x1Fb\x1Fc", i.e. separated by U+001F, with a signalling U+001F at the start.
	 *  - As a string[], e.g. from a query string like "foo[]=a&foo[]=b&foo[]=c".
	 *
	 * Each of the multiple values is passed individually to the TypeDef.
	 * $options will contain a 'values-list' key holding the entire list.
	 *
	 * By default duplicates are removed from the resulting parameter list. Use
	 * PARAM_ALLOW_DUPLICATES to override that behavior.
	 *
	 * Failure codes:
	 *  - 'toomanyvalues': More values were supplied than are allowed. See
	 *    PARAM_ISMULTI_LIMIT1, PARAM_ISMULTI_LIMIT2, and constructor option
	 *    'ismultiLimits'. Data:
	 *     - 'limit': The limit currently in effect.
	 *     - 'lowlimit': The limit when high limits are not allowed.
	 *     - 'highlimit': The limit when high limits are allowed.
	 *  - 'unrecognizedvalues': Non-fatal. Invalid values were passed and
	 *    PARAM_IGNORE_UNRECOGNIZED_VALUES was set. Data:
	 *     - 'values': The unrecognized values.
	 */
	public const PARAM_ISMULTI = 'param-ismulti';

	/**
	 * (int) Maximum number of multi-valued parameter values allowed
	 *
	 * @see PARAM_ISMULTI
	 */
	public const PARAM_ISMULTI_LIMIT1 = 'param-ismulti-limit1';

	/**
	 * (int) Maximum number of multi-valued parameter values allowed for users
	 * allowed high limits.
	 *
	 * @see PARAM_ISMULTI
	 */
	public const PARAM_ISMULTI_LIMIT2 = 'param-ismulti-limit2';

	/**
	 * (bool|string) Whether a magic "all values" value exists for multi-valued
	 * enumerated types, and if so what that value is.
	 *
	 * When PARAM_TYPE has a defined set of values and PARAM_ISMULTI is true,
	 * this allows for an asterisk ('*') to be passed in place of a pipe-separated list of
	 * every possible value. If a string is set, it will be used in place of the asterisk.
	 */
	public const PARAM_ALL = 'param-all';

	/**
	 * (bool) Allow the same value to be set more than once when PARAM_ISMULTI is true?
	 *
	 * If not truthy, the set of values will be passed through
	 * `array_values( array_unique() )`. The default is falsey.
	 */
	public const PARAM_ALLOW_DUPLICATES = 'param-allow-duplicates';

	/**
	 * (bool) Indicate that the parameter's value should not be logged.
	 *
	 * Failure codes: (non-fatal)
	 *  - 'param-sensitive': Always recorded when the parameter is used.
	 */
	public const PARAM_SENSITIVE = 'param-sensitive';

	/**
	 * (bool) Indicate that a deprecated parameter was used.
	 *
	 * Failure codes: (non-fatal)
	 *  - 'param-deprecated': Always recorded when the parameter is used.
	 */
	public const PARAM_DEPRECATED = 'param-deprecated';

	/**
	 * (bool) Whether to downgrade "badvalue" errors to non-fatal when validating multi-valued
	 * parameters.
	 * @see PARAM_ISMULTI
	 */
	public const PARAM_IGNORE_UNRECOGNIZED_VALUES = 'param-ignore-unrecognized-values';

	/** @} */
	// endregion -- end of Constants for parameter settings arrays

	/**
	 * @see TypeDef::OPT_ENFORCE_JSON_TYPES
	 */
	public const OPT_ENFORCE_JSON_TYPES = TypeDef::OPT_ENFORCE_JSON_TYPES;

	/** Magic "all values" value when PARAM_ALL is true. */
	public const ALL_DEFAULT_STRING = '*';

	/** A list of standard type names and types that may be passed as `$typeDefs` to __construct(). */
	public const STANDARD_TYPES = [
		'boolean' => [ 'class' => TypeDef\BooleanDef::class ],
		'checkbox' => [ 'class' => TypeDef\PresenceBooleanDef::class ],
		'integer' => [ 'class' => TypeDef\IntegerDef::class ],
		'limit' => [ 'class' => TypeDef\LimitDef::class ],
		'float' => [ 'class' => TypeDef\FloatDef::class ],
		'double' => [ 'class' => TypeDef\FloatDef::class ],
		'string' => [ 'class' => TypeDef\StringDef::class ],
		'password' => [ 'class' => TypeDef\PasswordDef::class ],
		'NULL' => [
			'class' => TypeDef\StringDef::class,
			'args' => [ [
				TypeDef\StringDef::OPT_ALLOW_EMPTY => true,
			] ],
		],
		'timestamp' => [ 'class' => TypeDef\TimestampDef::class ],
		'upload' => [ 'class' => TypeDef\UploadDef::class ],
		'enum' => [ 'class' => TypeDef\EnumDef::class ],
		'expiry' => [ 'class' => TypeDef\ExpiryDef::class ],
	];

	/** @var Callbacks */
	private $callbacks;

	/** @var ObjectFactory */
	private $objectFactory;

	/** @var (TypeDef|array)[] Map parameter type names to TypeDef objects or ObjectFactory specs */
	private $typeDefs = [];

	/** @var int Default values for PARAM_ISMULTI_LIMIT1 */
	private $ismultiLimit1;

	/** @var int Default values for PARAM_ISMULTI_LIMIT2 */
	private $ismultiLimit2;

	/**
	 * @param Callbacks $callbacks
	 * @param ObjectFactory $objectFactory To turn specs into TypeDef objects
	 * @param array $options Associative array of additional settings
	 *  - 'typeDefs': (array) As for addTypeDefs(). If omitted, self::STANDARD_TYPES will be used.
	 *    Pass an empty array if you want to start with no registered types.
	 *  - 'ismultiLimits': (int[]) Two ints, being the default values for PARAM_ISMULTI_LIMIT1 and
	 *    PARAM_ISMULTI_LIMIT2. If not given, defaults to `[ 50, 500 ]`.
	 */
	public function __construct(
		Callbacks $callbacks,
		ObjectFactory $objectFactory,
		array $options = []
	) {
		$this->callbacks = $callbacks;
		$this->objectFactory = $objectFactory;

		$this->addTypeDefs( $options['typeDefs'] ?? self::STANDARD_TYPES );
		$this->ismultiLimit1 = $options['ismultiLimits'][0] ?? 50;
		$this->ismultiLimit2 = $options['ismultiLimits'][1] ?? 500;
	}

	/**
	 * List known type names
	 * @return string[]
	 */
	public function knownTypes() {
		return array_keys( $this->typeDefs );
	}

	/**
	 * Register multiple type handlers
	 *
	 * @see addTypeDef()
	 * @param array $typeDefs Associative array mapping `$name` to `$typeDef`.
	 */
	public function addTypeDefs( array $typeDefs ) {
		foreach ( $typeDefs as $name => $def ) {
			$this->addTypeDef( $name, $def );
		}
	}

	/**
	 * Register a type handler
	 *
	 * To allow code to omit PARAM_TYPE in settings arrays to derive the type
	 * from PARAM_DEFAULT, it is strongly recommended that the following types be
	 * registered: "boolean", "integer", "double", "string", "NULL", and "enum".
	 *
	 * When using ObjectFactory specs, the following extra arguments are passed:
	 * - The Callbacks object for this ParamValidator instance.
	 *
	 * @param string $name Type name
	 * @param TypeDef|array $typeDef Type handler or ObjectFactory spec to create one.
	 */
	public function addTypeDef( $name, $typeDef ) {
		Assert::parameterType(
			[ TypeDef::class, 'array' ],
			$typeDef,
			'$typeDef'
		);

		if ( isset( $this->typeDefs[$name] ) ) {
			throw new InvalidArgumentException( "Type '$name' is already registered" );
		}
		$this->typeDefs[$name] = $typeDef;
	}

	/**
	 * Register a type handler, overriding any existing handler
	 * @see addTypeDef
	 * @param string $name Type name
	 * @param TypeDef|array|null $typeDef As for addTypeDef, or null to unregister a type.
	 */
	public function overrideTypeDef( $name, $typeDef ) {
		Assert::parameterType(
			[ TypeDef::class, 'array', 'null' ],
			$typeDef,
			'$typeDef'
		);

		if ( $typeDef === null ) {
			unset( $this->typeDefs[$name] );
		} else {
			$this->typeDefs[$name] = $typeDef;
		}
	}

	/**
	 * Test if a type is registered
	 * @param string $name Type name
	 * @return bool
	 */
	public function hasTypeDef( $name ) {
		return isset( $this->typeDefs[$name] );
	}

	/**
	 * Get the TypeDef for a type
	 * @param string|array $type Any array is considered equivalent to the string "enum".
	 * @return TypeDef|null
	 */
	public function getTypeDef( $type ) {
		if ( is_array( $type ) ) {
			$type = 'enum';
		}

		if ( !isset( $this->typeDefs[$type] ) ) {
			return null;
		}

		$def = $this->typeDefs[$type];
		if ( !$def instanceof TypeDef ) {
			$def = $this->objectFactory->createObject( $def, [
				'extraArgs' => [ $this->callbacks ],
				'assertClass' => TypeDef::class,
			] );
			$this->typeDefs[$type] = $def;
		}

		return $def;
	}

	/**
	 * Logic shared by normalizeSettings() and checkSettings()
	 * @param array|mixed $settings
	 * @return array
	 */
	private function normalizeSettingsInternal( $settings ) {
		// Shorthand
		if ( !is_array( $settings ) ) {
			$settings = [
				self::PARAM_DEFAULT => $settings,
			];
		}

		// When type is not given, determine it from the type of the PARAM_DEFAULT
		if ( !isset( $settings[self::PARAM_TYPE] ) ) {
			$settings[self::PARAM_TYPE] = gettype( $settings[self::PARAM_DEFAULT] ?? null );
		}

		return $settings;
	}

	/**
	 * Normalize a parameter settings array
	 * @param array|mixed $settings Default value or an array of settings
	 *  using PARAM_* constants.
	 * @return array
	 */
	public function normalizeSettings( $settings ) {
		$settings = $this->normalizeSettingsInternal( $settings );

		$typeDef = $this->getTypeDef( $settings[self::PARAM_TYPE] );
		if ( $typeDef ) {
			$settings = $typeDef->normalizeSettings( $settings );
		}

		return $settings;
	}

	/**
	 * Validate a parameter settings array
	 *
	 * This is intended for validation of parameter settings during unit or
	 * integration testing, and should implement strict checks.
	 *
	 * The rest of the code should generally be more permissive.
	 *
	 * @param string $name Parameter name
	 * @param array|mixed $settings Default value or an array of settings
	 *  using PARAM_* constants.
	 * @param array $options Options array, passed through to the TypeDef and Callbacks.
	 * @return array
	 *  - 'issues': (string[]) Errors detected in $settings, as English text. If the settings
	 *    are valid, this will be the empty array.
	 *  - 'allowedKeys': (string[]) ParamValidator keys that are allowed in `$settings`.
	 *  - 'messages': (MessageValue[]) Messages to be checked for existence.
	 */
	public function checkSettings( string $name, $settings, array $options ): array {
		$settings = $this->normalizeSettingsInternal( $settings );
		$issues = [];
		$allowedKeys = [
			self::PARAM_TYPE, self::PARAM_DEFAULT, self::PARAM_REQUIRED, self::PARAM_ISMULTI,
			self::PARAM_SENSITIVE, self::PARAM_DEPRECATED, self::PARAM_IGNORE_UNRECOGNIZED_VALUES,
		];
		$messages = [];

		$type = $settings[self::PARAM_TYPE];
		$typeDef = null;
		if ( !is_string( $type ) && !is_array( $type ) ) {
			$issues[self::PARAM_TYPE] = 'PARAM_TYPE must be a string or array, got ' . gettype( $type );
		} else {
			$typeDef = $this->getTypeDef( $settings[self::PARAM_TYPE] );
			if ( !$typeDef ) {
				if ( is_array( $type ) ) {
					$type = 'enum';
				}
				$issues[self::PARAM_TYPE] = "Unknown/unregistered PARAM_TYPE \"$type\"";
			}
		}

		if ( isset( $settings[self::PARAM_DEFAULT] ) ) {
			try {
				$this->validateValue(
					$name, $settings[self::PARAM_DEFAULT], $settings, [ 'is-default' => true ] + $options
				);
			} catch ( ValidationException $ex ) {
				$issues[self::PARAM_DEFAULT] = 'Value for PARAM_DEFAULT does not validate (code '
					. $ex->getFailureMessage()->getCode() . ')';
			}
		}

		if ( !is_bool( $settings[self::PARAM_REQUIRED] ?? false ) ) {
			$issues[self::PARAM_REQUIRED] = 'PARAM_REQUIRED must be boolean, got '
				. gettype( $settings[self::PARAM_REQUIRED] );
		}

		if ( !is_bool( $settings[self::PARAM_ISMULTI] ?? false ) ) {
			$issues[self::PARAM_ISMULTI] = 'PARAM_ISMULTI must be boolean, got '
				. gettype( $settings[self::PARAM_ISMULTI] );
		}

		if ( !empty( $settings[self::PARAM_ISMULTI] ) ) {
			$allowedKeys = array_merge( $allowedKeys, [
				self::PARAM_ISMULTI_LIMIT1, self::PARAM_ISMULTI_LIMIT2,
				self::PARAM_ALL, self::PARAM_ALLOW_DUPLICATES
			] );

			$limit1 = $settings[self::PARAM_ISMULTI_LIMIT1] ?? $this->ismultiLimit1;
			$limit2 = $settings[self::PARAM_ISMULTI_LIMIT2] ?? $this->ismultiLimit2;
			if ( !is_int( $limit1 ) ) {
				$issues[self::PARAM_ISMULTI_LIMIT1] = 'PARAM_ISMULTI_LIMIT1 must be an integer, got '
					. gettype( $settings[self::PARAM_ISMULTI_LIMIT1] );
			} elseif ( $limit1 <= 0 ) {
				$issues[self::PARAM_ISMULTI_LIMIT1] =
					"PARAM_ISMULTI_LIMIT1 must be greater than 0, got $limit1";
			}
			if ( !is_int( $limit2 ) ) {
				$issues[self::PARAM_ISMULTI_LIMIT2] = 'PARAM_ISMULTI_LIMIT2 must be an integer, got '
					. gettype( $settings[self::PARAM_ISMULTI_LIMIT2] );
			} elseif ( $limit2 < $limit1 ) {
				$issues[self::PARAM_ISMULTI_LIMIT2] =
					'PARAM_ISMULTI_LIMIT2 must be greater than or equal to PARAM_ISMULTI_LIMIT1, but '
					. "$limit2 < $limit1";
			}

			$all = $settings[self::PARAM_ALL] ?? false;
			if ( !is_string( $all ) && !is_bool( $all ) ) {
				$issues[self::PARAM_ALL] = 'PARAM_ALL must be a string or boolean, got ' . gettype( $all );
			} elseif ( $all !== false && $typeDef ) {
				if ( $all === true ) {
					$all = self::ALL_DEFAULT_STRING;
				}
				$values = $typeDef->getEnumValues( $name, $settings, $options );
				if ( !is_array( $values ) ) {
					$issues[self::PARAM_ALL] = 'PARAM_ALL cannot be used with non-enumerated types';
				} elseif ( in_array( $all, $values, true ) ) {
					$issues[self::PARAM_ALL] = 'Value for PARAM_ALL conflicts with an enumerated value';
				}
			}

			if ( !is_bool( $settings[self::PARAM_ALLOW_DUPLICATES] ?? false ) ) {
				$issues[self::PARAM_ALLOW_DUPLICATES] = 'PARAM_ALLOW_DUPLICATES must be boolean, got '
					. gettype( $settings[self::PARAM_ALLOW_DUPLICATES] );
			}
		}

		if ( !is_bool( $settings[self::PARAM_SENSITIVE] ?? false ) ) {
			$issues[self::PARAM_SENSITIVE] = 'PARAM_SENSITIVE must be boolean, got '
				. gettype( $settings[self::PARAM_SENSITIVE] );
		}

		if ( !is_bool( $settings[self::PARAM_DEPRECATED] ?? false ) ) {
			$issues[self::PARAM_DEPRECATED] = 'PARAM_DEPRECATED must be boolean, got '
				. gettype( $settings[self::PARAM_DEPRECATED] );
		}

		if ( !is_bool( $settings[self::PARAM_IGNORE_UNRECOGNIZED_VALUES] ?? false ) ) {
			$issues[self::PARAM_IGNORE_UNRECOGNIZED_VALUES] = 'PARAM_IGNORE_UNRECOGNIZED_VALUES must be '
				. 'boolean, got ' . gettype( $settings[self::PARAM_IGNORE_UNRECOGNIZED_VALUES] );
		}

		$ret = [ 'issues' => $issues, 'allowedKeys' => $allowedKeys, 'messages' => $messages ];
		if ( $typeDef ) {
			$ret = $typeDef->checkSettings( $name, $settings, $options, $ret );
		}

		return $ret;
	}

	/**
	 * Fetch and validate a parameter value using a settings array
	 *
	 * @param string $name Parameter name
	 * @param array|mixed $settings Default value or an array of settings
	 *  using PARAM_* constants.
	 * @param array $options Options array, passed through to the TypeDef and Callbacks.
	 *  - An additional option, 'is-default', will be set when the value comes from PARAM_DEFAULT.
	 * @return mixed Validated parameter value
	 * @throws ValidationException if the value is invalid
	 */
	public function getValue( $name, $settings, array $options = [] ) {
		$settings = $this->normalizeSettings( $settings );

		$typeDef = $this->getTypeDef( $settings[self::PARAM_TYPE] );
		if ( !$typeDef ) {
			throw new DomainException(
				"Param $name's type is unknown - {$settings[self::PARAM_TYPE]}"
			);
		}

		$value = $typeDef->getValue( $name, $settings, $options );

		if ( $value !== null ) {
			if ( !empty( $settings[self::PARAM_SENSITIVE] ) ) {
				$strValue = $typeDef->stringifyValue( $name, $value, $settings, $options );
				$this->callbacks->recordCondition(
					DataMessageValue::new( 'paramvalidator-param-sensitive', [], 'param-sensitive' )
						->plaintextParams( $name, $strValue ),
					$name, $value, $settings, $options
				);
			}

			// Set a warning if a deprecated parameter has been passed
			if ( !empty( $settings[self::PARAM_DEPRECATED] ) ) {
				$strValue = $typeDef->stringifyValue( $name, $value, $settings, $options );
				$this->callbacks->recordCondition(
					DataMessageValue::new( 'paramvalidator-param-deprecated', [], 'param-deprecated' )
						->plaintextParams( $name, $strValue ),
					$name, $value, $settings, $options
				);
			}
		} elseif ( isset( $settings[self::PARAM_DEFAULT] ) ) {
			$value = $settings[self::PARAM_DEFAULT];
			$options['is-default'] = true;
		}

		return $this->validateValue( $name, $value, $settings, $options );
	}

	/**
	 * Validate a parameter value using a settings array
	 *
	 * @param string $name Parameter name
	 * @param null|mixed $value Parameter value
	 * @param array|mixed $settings Default value or an array of settings
	 *  using PARAM_* constants.
	 * @param array $options Options array, passed through to the TypeDef and Callbacks.
	 *  - An additional option, 'values-list', will be set when processing the
	 *    values of a multi-valued parameter.
	 * @return mixed Validated parameter value(s)
	 * @throws ValidationException if the value is invalid
	 */
	public function validateValue( $name, $value, $settings, array $options = [] ) {
		$settings = $this->normalizeSettings( $settings );

		$typeDef = $this->getTypeDef( $settings[self::PARAM_TYPE] );
		if ( !$typeDef ) {
			throw new DomainException(
				"Param $name's type is unknown - {$settings[self::PARAM_TYPE]}"
			);
		}

		if ( $value === null ) {
			if ( !empty( $settings[self::PARAM_REQUIRED] ) ) {
				throw new ValidationException(
					DataMessageValue::new( 'paramvalidator-missingparam', [], 'missingparam' )
						->plaintextParams( $name ),
					$name, $value, $settings
				);
			}
			return null;
		}

		// Non-multi
		if ( empty( $settings[self::PARAM_ISMULTI] ) ) {
			if ( is_string( $value ) && substr( $value, 0, 1 ) === "\x1f" ) {
				throw new ValidationException(
					DataMessageValue::new( 'paramvalidator-notmulti', [], 'badvalue' )
						->plaintextParams( $name, $value ),
					$name, $value, $settings
				);
			}

			// T326764: If the type of the actual param value is different from
			// the type that is defined via getParamSettings(), throw an exception
			// because this is a type to value mismatch.
			if ( is_array( $value ) && !$typeDef->supportsArrays() ) {
				throw new ValidationException(
					DataMessageValue::new( 'paramvalidator-notmulti', [], 'badvalue' )
						->plaintextParams( $name, gettype( $value ) ),
					$name, $value, $settings
				);
			}

			return $typeDef->validate( $name, $value, $settings, $options );
		}

		// Split the multi-value and validate each parameter
		$limit1 = $settings[self::PARAM_ISMULTI_LIMIT1] ?? $this->ismultiLimit1;
		$limit2 = max( $limit1, $settings[self::PARAM_ISMULTI_LIMIT2] ?? $this->ismultiLimit2 );

		if ( is_array( $value ) ) {
			$valuesList = $value;
		} elseif ( $options[ self::OPT_ENFORCE_JSON_TYPES ] ?? false ) {
			throw new ValidationException(
				DataMessageValue::new(
					'paramvalidator-multivalue-must-be-array',
					[],
					'multivalue-must-be-array'
				)->plaintextParams( $name ),
				$name, $value, $settings
			);
		} else {
			$valuesList = self::explodeMultiValue( $value, $limit2 + 1 );
		}

		// Handle PARAM_ALL
		$enumValues = $typeDef->getEnumValues( $name, $settings, $options );
		if ( is_array( $enumValues ) && isset( $settings[self::PARAM_ALL] ) &&
			count( $valuesList ) === 1
		) {
			$allValue = is_string( $settings[self::PARAM_ALL] )
				? $settings[self::PARAM_ALL]
				: self::ALL_DEFAULT_STRING;
			if ( $valuesList[0] === $allValue ) {
				return $enumValues;
			}
		}

		// Avoid checking useHighLimits() unless it's actually necessary
		$sizeLimit = (
			$limit2 > $limit1 && count( $valuesList ) > $limit1 &&
			$this->callbacks->useHighLimits( $options )
		) ? $limit2 : $limit1;
		if ( count( $valuesList ) > $sizeLimit ) {
			throw new ValidationException(
				DataMessageValue::new( 'paramvalidator-toomanyvalues', [], 'toomanyvalues', [
					'parameter' => $name,
					'limit' => $sizeLimit,
					'lowlimit' => $limit1,
					'highlimit' => $limit2,
				] )->plaintextParams( $name )->numParams( $sizeLimit ),
				$name, $valuesList, $settings
			);
		}

		$options['values-list'] = $valuesList;
		$validValues = [];
		$invalidValues = [];
		foreach ( $valuesList as $v ) {
			try {
				$validValues[] = $typeDef->validate( $name, $v, $settings, $options );
			} catch ( ValidationException $ex ) {
				if ( $ex->getFailureMessage()->getCode() !== 'badvalue' ||
					empty( $settings[self::PARAM_IGNORE_UNRECOGNIZED_VALUES] )
				) {
					throw $ex;
				}
				$invalidValues[] = $v;
			}
		}
		if ( $invalidValues ) {
			if ( is_array( $value ) ) {
				$value = self::implodeMultiValue( $value );
			}
			$this->callbacks->recordCondition(
				DataMessageValue::new( 'paramvalidator-unrecognizedvalues', [], 'unrecognizedvalues', [
					'values' => $invalidValues,
				] )
					->plaintextParams( $name, $value )
					->commaListParams( array_map( static function ( $v ) {
						return new ScalarParam( ParamType::PLAINTEXT, $v );
					}, $invalidValues ) )
					->numParams( count( $invalidValues ) ),
				$name, $value, $settings, $options
			);
		}

		// Throw out duplicates if requested
		if ( empty( $settings[self::PARAM_ALLOW_DUPLICATES] ) ) {
			$validValues = array_values( array_unique( $validValues ) );
		}

		return $validValues;
	}

	/**
	 * Describe parameter settings in a machine-readable format.
	 *
	 * @param string $name Parameter name.
	 * @param array|mixed $settings Default value or an array of settings
	 *  using PARAM_* constants.
	 * @param array $options Options array.
	 * @return array
	 */
	public function getParamInfo( $name, $settings, array $options ) {
		$settings = $this->normalizeSettings( $settings );
		$typeDef = $this->getTypeDef( $settings[self::PARAM_TYPE] );
		$info = [];

		$info['type'] = $settings[self::PARAM_TYPE];
		$info['required'] = !empty( $settings[self::PARAM_REQUIRED] );
		if ( !empty( $settings[self::PARAM_DEPRECATED] ) ) {
			$info['deprecated'] = true;
		}
		if ( !empty( $settings[self::PARAM_SENSITIVE] ) ) {
			$info['sensitive'] = true;
		}
		if ( isset( $settings[self::PARAM_DEFAULT] ) ) {
			$info['default'] = $settings[self::PARAM_DEFAULT];
		}
		$info['multi'] = !empty( $settings[self::PARAM_ISMULTI] );
		if ( $info['multi'] ) {
			$info['lowlimit'] = $settings[self::PARAM_ISMULTI_LIMIT1] ?? $this->ismultiLimit1;
			$info['highlimit'] = max(
				$info['lowlimit'], $settings[self::PARAM_ISMULTI_LIMIT2] ?? $this->ismultiLimit2
			);
			$info['limit'] =
				$info['highlimit'] > $info['lowlimit'] && $this->callbacks->useHighLimits( $options )
					? $info['highlimit']
					: $info['lowlimit'];

			if ( !empty( $settings[self::PARAM_ALLOW_DUPLICATES] ) ) {
				$info['allowsduplicates'] = true;
			}

			$allSpecifier = $settings[self::PARAM_ALL] ?? false;
			if ( $allSpecifier !== false ) {
				if ( !is_string( $allSpecifier ) ) {
					$allSpecifier = self::ALL_DEFAULT_STRING;
				}
				$info['allspecifier'] = $allSpecifier;
			}
		}

		if ( $typeDef ) {
			$info = array_merge( $info, $typeDef->getParamInfo( $name, $settings, $options ) );
		}

		// Filter out nulls (strictly)
		return array_filter( $info, static function ( $v ) {
			return $v !== null;
		} );
	}

	/**
	 * Describe parameter settings in human-readable format
	 *
	 * @param string $name Parameter name being described.
	 * @param array|mixed $settings Default value or an array of settings
	 *  using PARAM_* constants.
	 * @param array $options Options array.
	 * @return MessageValue[]
	 */
	public function getHelpInfo( $name, $settings, array $options ) {
		$settings = $this->normalizeSettings( $settings );
		$typeDef = $this->getTypeDef( $settings[self::PARAM_TYPE] );

		// Define ordering. Some are overwritten below, some expected from the TypeDef
		$info = [
			self::PARAM_DEPRECATED => null,
			self::PARAM_REQUIRED => null,
			self::PARAM_SENSITIVE => null,
			self::PARAM_TYPE => null,
			self::PARAM_ISMULTI => null,
			self::PARAM_ISMULTI_LIMIT1 => null,
			self::PARAM_ALL => null,
			self::PARAM_DEFAULT => null,
		];

		if ( !empty( $settings[self::PARAM_DEPRECATED] ) ) {
			$info[self::PARAM_DEPRECATED] = MessageValue::new( 'paramvalidator-help-deprecated' );
		}

		if ( !empty( $settings[self::PARAM_REQUIRED] ) ) {
			$info[self::PARAM_REQUIRED] = MessageValue::new( 'paramvalidator-help-required' );
		}

		if ( !empty( $settings[self::PARAM_ISMULTI] ) ) {
			$info[self::PARAM_ISMULTI] = MessageValue::new( 'paramvalidator-help-multi-separate' );

			$lowcount = $settings[self::PARAM_ISMULTI_LIMIT1] ?? $this->ismultiLimit1;
			$highcount = max( $lowcount, $settings[self::PARAM_ISMULTI_LIMIT2] ?? $this->ismultiLimit2 );
			$values = $typeDef ? $typeDef->getEnumValues( $name, $settings, $options ) : null;
			if (
				// Only mention the limits if they're likely to matter.
				$values === null || count( $values ) > $lowcount ||
				!empty( $settings[self::PARAM_ALLOW_DUPLICATES] )
			) {
				if ( $highcount > $lowcount ) {
					$info[self::PARAM_ISMULTI_LIMIT1] = MessageValue::new( 'paramvalidator-help-multi-max' )
						->numParams( $lowcount, $highcount );
				} else {
					$info[self::PARAM_ISMULTI_LIMIT1] = MessageValue::new( 'paramvalidator-help-multi-max-simple' )
						->numParams( $lowcount );
				}
			}

			$allSpecifier = $settings[self::PARAM_ALL] ?? false;
			if ( $allSpecifier !== false ) {
				if ( !is_string( $allSpecifier ) ) {
					$allSpecifier = self::ALL_DEFAULT_STRING;
				}
				$info[self::PARAM_ALL] = MessageValue::new( 'paramvalidator-help-multi-all' )
					->plaintextParams( $allSpecifier );
			}
		}

		if ( isset( $settings[self::PARAM_DEFAULT] ) && $typeDef ) {
			$value = $typeDef->stringifyValue( $name, $settings[self::PARAM_DEFAULT], $settings, $options );
			if ( $value === '' ) {
				$info[self::PARAM_DEFAULT] = MessageValue::new( 'paramvalidator-help-default-empty' );
			} elseif ( $value !== null ) {
				$info[self::PARAM_DEFAULT] = MessageValue::new( 'paramvalidator-help-default' )
					->plaintextParams( $value );
			}
		}

		if ( $typeDef ) {
			$info = array_merge( $info, $typeDef->getHelpInfo( $name, $settings, $options ) );
		}

		// Put the default at the very end (the TypeDef may have added extra messages)
		$default = $info[self::PARAM_DEFAULT];
		unset( $info[self::PARAM_DEFAULT] );
		$info[self::PARAM_DEFAULT] = $default;

		// Filter out nulls
		return array_filter( $info );
	}

	/**
	 * Split a multi-valued parameter string, like explode()
	 *
	 * Note that, unlike explode(), this will return an empty array when given
	 * an empty string.
	 *
	 * @param string $value
	 * @param int $limit
	 * @return string[]
	 */
	public static function explodeMultiValue( $value, $limit ) {
		if ( $value === '' || $value === "\x1f" ) {
			return [];
		}

		if ( substr( $value, 0, 1 ) === "\x1f" ) {
			$sep = "\x1f";
			$value = substr( $value, 1 );
		} else {
			$sep = '|';
		}

		return explode( $sep, $value, $limit );
	}

	/**
	 * Implode an array as a multi-valued parameter string, like implode()
	 *
	 * @param array $value
	 * @return string
	 */
	public static function implodeMultiValue( array $value ) {
		if ( $value === [ '' ] ) {
			// There's no value that actually returns a single empty string.
			// Best we can do is this that returns two, which will be deduplicated to one.
			return '|';
		}

		foreach ( $value as $v ) {
			if ( strpos( $v, '|' ) !== false ) {
				return "\x1f" . implode( "\x1f", $value );
			}
		}
		return implode( '|', $value );
	}

}