forked from json-schema-org/json-schema-org.github.io
-
Notifications
You must be signed in to change notification settings - Fork 4
/
Copy pathjson-schema-validation.html
1397 lines (1329 loc) · 84.2 KB
/
json-schema-validation.html
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
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html lang="en" xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head profile="http://www.w3.org/2006/03/hcard http://dublincore.org/documents/2008/08/04/dc-html/">
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii" />
<title>JSON Schema Validation: A Vocabulary for Structural Validation of JSON </title>
<style type="text/css" title="Xml2Rfc (sans serif)">
/*<![CDATA[*/
a {
text-decoration: none;
}
/* info code from SantaKlauss at http://www.madaboutstyle.com/tooltip2.html */
a.info {
/* This is the key. */
position: relative;
z-index: 24;
text-decoration: none;
}
a.info:hover {
z-index: 25;
color: #FFF; background-color: #900;
}
a.info span { display: none; }
a.info:hover span.info {
/* The span will display just on :hover state. */
display: block;
position: absolute;
font-size: smaller;
top: 2em; left: -5em; width: 15em;
padding: 2px; border: 1px solid #333;
color: #900; background-color: #EEE;
text-align: left;
}
a.smpl {
color: black;
}
a:hover {
text-decoration: underline;
}
a:active {
text-decoration: underline;
}
address {
margin-top: 1em;
margin-left: 2em;
font-style: normal;
}
body {
color: black;
font-family: verdana, helvetica, arial, sans-serif;
font-size: 10pt;
max-width: 55em;
}
cite {
font-style: normal;
}
dd {
margin-right: 2em;
}
dl {
margin-left: 2em;
}
ul.empty {
list-style-type: none;
}
ul.empty li {
margin-top: .5em;
}
dl p {
margin-left: 0em;
}
dt {
margin-top: .5em;
}
h1 {
font-size: 14pt;
line-height: 21pt;
page-break-after: avoid;
}
h1.np {
page-break-before: always;
}
h1 a {
color: #333333;
}
h2 {
font-size: 12pt;
line-height: 15pt;
page-break-after: avoid;
}
h3, h4, h5, h6 {
font-size: 10pt;
page-break-after: avoid;
}
h2 a, h3 a, h4 a, h5 a, h6 a {
color: black;
}
img {
margin-left: 3em;
}
li {
margin-left: 2em;
margin-right: 2em;
}
ol {
margin-left: 2em;
margin-right: 2em;
}
ol p {
margin-left: 0em;
}
p {
margin-left: 2em;
margin-right: 2em;
}
pre {
margin-left: 3em;
background-color: lightyellow;
padding: .25em;
}
pre.text2 {
border-style: dotted;
border-width: 1px;
background-color: #f0f0f0;
width: 69em;
}
pre.inline {
background-color: white;
padding: 0em;
}
pre.text {
border-style: dotted;
border-width: 1px;
background-color: #f8f8f8;
width: 69em;
}
pre.drawing {
border-style: solid;
border-width: 1px;
background-color: #f8f8f8;
padding: 2em;
}
table {
margin-left: 2em;
}
table.tt {
vertical-align: top;
}
table.full {
border-style: outset;
border-width: 1px;
}
table.headers {
border-style: outset;
border-width: 1px;
}
table.tt td {
vertical-align: top;
}
table.full td {
border-style: inset;
border-width: 1px;
}
table.tt th {
vertical-align: top;
}
table.full th {
border-style: inset;
border-width: 1px;
}
table.headers th {
border-style: none none inset none;
border-width: 1px;
}
table.left {
margin-right: auto;
}
table.right {
margin-left: auto;
}
table.center {
margin-left: auto;
margin-right: auto;
}
caption {
caption-side: bottom;
font-weight: bold;
font-size: 9pt;
margin-top: .5em;
}
table.header {
border-spacing: 1px;
width: 95%;
font-size: 10pt;
color: white;
}
td.top {
vertical-align: top;
}
td.topnowrap {
vertical-align: top;
white-space: nowrap;
}
table.header td {
background-color: gray;
width: 50%;
}
table.header a {
color: white;
}
td.reference {
vertical-align: top;
white-space: nowrap;
padding-right: 1em;
}
thead {
display:table-header-group;
}
ul.toc, ul.toc ul {
list-style: none;
margin-left: 1.5em;
margin-right: 0em;
padding-left: 0em;
}
ul.toc li {
line-height: 150%;
font-weight: bold;
font-size: 10pt;
margin-left: 0em;
margin-right: 0em;
}
ul.toc li li {
line-height: normal;
font-weight: normal;
font-size: 9pt;
margin-left: 0em;
margin-right: 0em;
}
li.excluded {
font-size: 0pt;
}
ul p {
margin-left: 0em;
}
.comment {
background-color: yellow;
}
.center {
text-align: center;
}
.error {
color: red;
font-style: italic;
font-weight: bold;
}
.figure {
font-weight: bold;
text-align: center;
font-size: 9pt;
}
.filename {
color: #333333;
font-weight: bold;
font-size: 12pt;
line-height: 21pt;
text-align: center;
}
.fn {
font-weight: bold;
}
.hidden {
display: none;
}
.left {
text-align: left;
}
.right {
text-align: right;
}
.title {
color: #990000;
font-size: 18pt;
line-height: 18pt;
font-weight: bold;
text-align: center;
margin-top: 36pt;
}
.vcardline {
display: block;
}
.warning {
font-size: 14pt;
background-color: yellow;
}
@media print {
.noprint {
display: none;
}
a {
color: black;
text-decoration: none;
}
table.header {
width: 90%;
}
td.header {
width: 50%;
color: black;
background-color: white;
vertical-align: top;
font-size: 12pt;
}
ul.toc a::after {
content: leader('.') target-counter(attr(href), page);
}
ul.ind li li a {
content: target-counter(attr(href), page);
}
.print2col {
column-count: 2;
-moz-column-count: 2;
column-fill: auto;
}
}
@page {
@top-left {
content: "Internet-Draft";
}
@top-right {
content: "December 2010";
}
@top-center {
content: "Abbreviated Title";
}
@bottom-left {
content: "Doe";
}
@bottom-center {
content: "Expires June 2011";
}
@bottom-right {
content: "[Page " counter(page) "]";
}
}
@page:first {
@top-left {
content: normal;
}
@top-right {
content: normal;
}
@top-center {
content: normal;
}
}
/*]]>*/
</style>
<link href="#rfc.toc" rel="Contents">
<link href="#rfc.section.1" rel="Chapter" title="1 Introduction">
<link href="#rfc.section.2" rel="Chapter" title="2 Conventions and Terminology">
<link href="#rfc.section.3" rel="Chapter" title="3 Overview">
<link href="#rfc.section.4" rel="Chapter" title="4 Interoperability Considerations">
<link href="#rfc.section.4.1" rel="Chapter" title="4.1 Validation of String Instances">
<link href="#rfc.section.4.2" rel="Chapter" title="4.2 Validation of Numeric Instances">
<link href="#rfc.section.4.3" rel="Chapter" title="4.3 Regular Expressions">
<link href="#rfc.section.5" rel="Chapter" title="5 Meta-Schema">
<link href="#rfc.section.6" rel="Chapter" title="6 A Vocabulary for Structural Validation">
<link href="#rfc.section.6.1" rel="Chapter" title="6.1 Validation Keywords for Any Instance Type">
<link href="#rfc.section.6.1.1" rel="Chapter" title="6.1.1 type">
<link href="#rfc.section.6.1.2" rel="Chapter" title="6.1.2 enum">
<link href="#rfc.section.6.1.3" rel="Chapter" title="6.1.3 const">
<link href="#rfc.section.6.2" rel="Chapter" title="6.2 Validation Keywords for Numeric Instances (number and integer)">
<link href="#rfc.section.6.2.1" rel="Chapter" title="6.2.1 multipleOf">
<link href="#rfc.section.6.2.2" rel="Chapter" title="6.2.2 maximum">
<link href="#rfc.section.6.2.3" rel="Chapter" title="6.2.3 exclusiveMaximum">
<link href="#rfc.section.6.2.4" rel="Chapter" title="6.2.4 minimum">
<link href="#rfc.section.6.2.5" rel="Chapter" title="6.2.5 exclusiveMinimum">
<link href="#rfc.section.6.3" rel="Chapter" title="6.3 Validation Keywords for Strings">
<link href="#rfc.section.6.3.1" rel="Chapter" title="6.3.1 maxLength">
<link href="#rfc.section.6.3.2" rel="Chapter" title="6.3.2 minLength">
<link href="#rfc.section.6.3.3" rel="Chapter" title="6.3.3 pattern">
<link href="#rfc.section.6.4" rel="Chapter" title="6.4 Validation Keywords for Arrays">
<link href="#rfc.section.6.4.1" rel="Chapter" title="6.4.1 maxItems">
<link href="#rfc.section.6.4.2" rel="Chapter" title="6.4.2 minItems">
<link href="#rfc.section.6.4.3" rel="Chapter" title="6.4.3 uniqueItems">
<link href="#rfc.section.6.4.4" rel="Chapter" title="6.4.4 maxContains">
<link href="#rfc.section.6.4.5" rel="Chapter" title="6.4.5 minContains">
<link href="#rfc.section.6.5" rel="Chapter" title="6.5 Validation Keywords for Objects">
<link href="#rfc.section.6.5.1" rel="Chapter" title="6.5.1 maxProperties">
<link href="#rfc.section.6.5.2" rel="Chapter" title="6.5.2 minProperties">
<link href="#rfc.section.6.5.3" rel="Chapter" title="6.5.3 required">
<link href="#rfc.section.6.5.4" rel="Chapter" title="6.5.4 dependentRequired">
<link href="#rfc.section.7" rel="Chapter" title='7 A Vocabulary for Semantic Content With "format"'>
<link href="#rfc.section.7.1" rel="Chapter" title="7.1 Foreword">
<link href="#rfc.section.7.2" rel="Chapter" title="7.2 Implementation Requirements">
<link href="#rfc.section.7.2.1" rel="Chapter" title="7.2.1 As an annotation">
<link href="#rfc.section.7.2.2" rel="Chapter" title="7.2.2 As an assertion">
<link href="#rfc.section.7.2.3" rel="Chapter" title="7.2.3 Custom format attributes">
<link href="#rfc.section.7.3" rel="Chapter" title="7.3 Defined Formats">
<link href="#rfc.section.7.3.1" rel="Chapter" title="7.3.1 Dates, Times, and Duration">
<link href="#rfc.section.7.3.2" rel="Chapter" title="7.3.2 Email Addresses">
<link href="#rfc.section.7.3.3" rel="Chapter" title="7.3.3 Hostnames">
<link href="#rfc.section.7.3.4" rel="Chapter" title="7.3.4 IP Addresses">
<link href="#rfc.section.7.3.5" rel="Chapter" title="7.3.5 Resource Identifiers">
<link href="#rfc.section.7.3.6" rel="Chapter" title="7.3.6 uri-template">
<link href="#rfc.section.7.3.7" rel="Chapter" title="7.3.7 JSON Pointers">
<link href="#rfc.section.7.3.8" rel="Chapter" title="7.3.8 regex">
<link href="#rfc.section.8" rel="Chapter" title="8 A Vocabulary for the Contents of String-Encoded Data">
<link href="#rfc.section.8.1" rel="Chapter" title="8.1 Foreword">
<link href="#rfc.section.8.2" rel="Chapter" title="8.2 Implementation Requirements">
<link href="#rfc.section.8.3" rel="Chapter" title="8.3 contentEncoding">
<link href="#rfc.section.8.4" rel="Chapter" title="8.4 contentMediaType">
<link href="#rfc.section.8.5" rel="Chapter" title="8.5 contentSchema">
<link href="#rfc.section.8.6" rel="Chapter" title="8.6 Example">
<link href="#rfc.section.9" rel="Chapter" title="9 A Vocabulary for Basic Meta-Data Annotations">
<link href="#rfc.section.9.1" rel="Chapter" title='9.1 "title" and "description"'>
<link href="#rfc.section.9.2" rel="Chapter" title='9.2 "default"'>
<link href="#rfc.section.9.3" rel="Chapter" title='9.3 "deprecated"'>
<link href="#rfc.section.9.4" rel="Chapter" title='9.4 "readOnly" and "writeOnly"'>
<link href="#rfc.section.9.5" rel="Chapter" title='9.5 "examples"'>
<link href="#rfc.section.10" rel="Chapter" title="10 Security Considerations">
<link href="#rfc.references" rel="Chapter" title="11 References">
<link href="#rfc.references.1" rel="Chapter" title="11.1 Normative References">
<link href="#rfc.references.2" rel="Chapter" title="11.2 Informative References">
<link href="#rfc.appendix.A" rel="Chapter" title="A Keywords Moved from Validation to Core">
<link href="#rfc.appendix.B" rel="Chapter" title="B Acknowledgments">
<link href="#rfc.appendix.C" rel="Chapter" title="C ChangeLog">
<link href="#rfc.authors" rel="Chapter">
<meta name="generator" content="xml2rfc version 2.20.1 - https://tools.ietf.org/tools/xml2rfc" />
<link rel="schema.dct" href="http://purl.org/dc/terms/" />
<meta name="dct.creator" content="Wright, A., Ed., Andrews, H., Ed., and B. Hutton, Ed." />
<meta name="dct.identifier" content="urn:ietf:id:draft-handrews-json-schema-validation-02" />
<meta name="dct.issued" scheme="ISO8601" content="2019-17" />
<meta name="dct.abstract" content="JSON Schema (application/schema+json) has several purposes, one of which is JSON instance validation. This document specifies a vocabulary for JSON Schema to describe the meaning of JSON documents, provide hints for user interfaces working with JSON data, and to make assertions about what a valid document must look like. " />
<meta name="description" content="JSON Schema (application/schema+json) has several purposes, one of which is JSON instance validation. This document specifies a vocabulary for JSON Schema to describe the meaning of JSON documents, provide hints for user interfaces working with JSON data, and to make assertions about what a valid document must look like. " />
</head>
<body>
<table class="header">
<tbody>
<tr>
<td class="left">Internet Engineering Task Force</td>
<td class="right">A. Wright, Ed.</td>
</tr>
<tr>
<td class="left">Internet-Draft</td>
<td class="right"></td>
</tr>
<tr>
<td class="left">Intended status: Informational</td>
<td class="right">H. Andrews, Ed.</td>
</tr>
<tr>
<td class="left">Expires: March 20, 2020</td>
<td class="right"></td>
</tr>
<tr>
<td class="left"></td>
<td class="right">B. Hutton, Ed.</td>
</tr>
<tr>
<td class="left"></td>
<td class="right">Wellcome Sanger Institute</td>
</tr>
<tr>
<td class="left"></td>
<td class="right">September 17, 2019</td>
</tr>
</tbody>
</table>
<p class="title">JSON Schema Validation: A Vocabulary for Structural Validation of JSON <br />
<span class="filename">draft-handrews-json-schema-validation-02</span></p>
<h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1>
<p>JSON Schema (application/schema+json) has several purposes, one of which is JSON instance validation. This document specifies a vocabulary for JSON Schema to describe the meaning of JSON documents, provide hints for user interfaces working with JSON data, and to make assertions about what a valid document must look like. </p>
<h1><a>Note to Readers</a></h1>
<p>The issues list for this draft can be found at <span><</span><a href="https://github.com/json-schema-org/json-schema-spec/issues">https://github.com/json-schema-org/json-schema-spec/issues</a><span>></span>. </p>
<p>For additional information, see <span><</span><a href="https://json-schema.org/">https://json-schema.org/</a><span>></span>. </p>
<p>To provide feedback, use this issue tracker, the communication methods listed on the homepage, or email the document editors. </p>
<h1 id="rfc.status"><a href="#rfc.status">Status of This Memo</a></h1>
<p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
<p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.</p>
<p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."</p>
<p>This Internet-Draft will expire on March 20, 2020.</p>
<h1 id="rfc.copyrightnotice"><a href="#rfc.copyrightnotice">Copyright Notice</a></h1>
<p>Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
<p>This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.</p>
<hr class="noprint" />
<h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
<ul class="toc">
<li>1. <a href="#rfc.section.1">Introduction</a>
</li>
<li>2. <a href="#rfc.section.2">Conventions and Terminology</a>
</li>
<li>3. <a href="#rfc.section.3">Overview</a>
</li>
<li>4. <a href="#rfc.section.4">Interoperability Considerations</a>
</li>
<ul><li>4.1. <a href="#rfc.section.4.1">Validation of String Instances</a>
</li>
<li>4.2. <a href="#rfc.section.4.2">Validation of Numeric Instances</a>
</li>
<li>4.3. <a href="#rfc.section.4.3">Regular Expressions</a>
</li>
</ul><li>5. <a href="#rfc.section.5">Meta-Schema</a>
</li>
<li>6. <a href="#rfc.section.6">A Vocabulary for Structural Validation</a>
</li>
<ul><li>6.1. <a href="#rfc.section.6.1">Validation Keywords for Any Instance Type</a>
</li>
<ul><li>6.1.1. <a href="#rfc.section.6.1.1">type</a>
</li>
<li>6.1.2. <a href="#rfc.section.6.1.2">enum</a>
</li>
<li>6.1.3. <a href="#rfc.section.6.1.3">const</a>
</li>
</ul><li>6.2. <a href="#rfc.section.6.2">Validation Keywords for Numeric Instances (number and integer)</a>
</li>
<ul><li>6.2.1. <a href="#rfc.section.6.2.1">multipleOf</a>
</li>
<li>6.2.2. <a href="#rfc.section.6.2.2">maximum</a>
</li>
<li>6.2.3. <a href="#rfc.section.6.2.3">exclusiveMaximum</a>
</li>
<li>6.2.4. <a href="#rfc.section.6.2.4">minimum</a>
</li>
<li>6.2.5. <a href="#rfc.section.6.2.5">exclusiveMinimum</a>
</li>
</ul><li>6.3. <a href="#rfc.section.6.3">Validation Keywords for Strings</a>
</li>
<ul><li>6.3.1. <a href="#rfc.section.6.3.1">maxLength</a>
</li>
<li>6.3.2. <a href="#rfc.section.6.3.2">minLength</a>
</li>
<li>6.3.3. <a href="#rfc.section.6.3.3">pattern</a>
</li>
</ul><li>6.4. <a href="#rfc.section.6.4">Validation Keywords for Arrays</a>
</li>
<ul><li>6.4.1. <a href="#rfc.section.6.4.1">maxItems</a>
</li>
<li>6.4.2. <a href="#rfc.section.6.4.2">minItems</a>
</li>
<li>6.4.3. <a href="#rfc.section.6.4.3">uniqueItems</a>
</li>
<li>6.4.4. <a href="#rfc.section.6.4.4">maxContains</a>
</li>
<li>6.4.5. <a href="#rfc.section.6.4.5">minContains</a>
</li>
</ul><li>6.5. <a href="#rfc.section.6.5">Validation Keywords for Objects</a>
</li>
<ul><li>6.5.1. <a href="#rfc.section.6.5.1">maxProperties</a>
</li>
<li>6.5.2. <a href="#rfc.section.6.5.2">minProperties</a>
</li>
<li>6.5.3. <a href="#rfc.section.6.5.3">required</a>
</li>
<li>6.5.4. <a href="#rfc.section.6.5.4">dependentRequired</a>
</li>
</ul></ul><li>7. <a href="#rfc.section.7">A Vocabulary for Semantic Content With "format"</a>
</li>
<ul><li>7.1. <a href="#rfc.section.7.1">Foreword</a>
</li>
<li>7.2. <a href="#rfc.section.7.2">Implementation Requirements</a>
</li>
<ul><li>7.2.1. <a href="#rfc.section.7.2.1">As an annotation</a>
</li>
<li>7.2.2. <a href="#rfc.section.7.2.2">As an assertion</a>
</li>
<li>7.2.3. <a href="#rfc.section.7.2.3">Custom format attributes</a>
</li>
</ul><li>7.3. <a href="#rfc.section.7.3">Defined Formats</a>
</li>
<ul><li>7.3.1. <a href="#rfc.section.7.3.1">Dates, Times, and Duration</a>
</li>
<li>7.3.2. <a href="#rfc.section.7.3.2">Email Addresses</a>
</li>
<li>7.3.3. <a href="#rfc.section.7.3.3">Hostnames</a>
</li>
<li>7.3.4. <a href="#rfc.section.7.3.4">IP Addresses</a>
</li>
<li>7.3.5. <a href="#rfc.section.7.3.5">Resource Identifiers</a>
</li>
<li>7.3.6. <a href="#rfc.section.7.3.6">uri-template</a>
</li>
<li>7.3.7. <a href="#rfc.section.7.3.7">JSON Pointers</a>
</li>
<li>7.3.8. <a href="#rfc.section.7.3.8">regex</a>
</li>
</ul></ul><li>8. <a href="#rfc.section.8">A Vocabulary for the Contents of String-Encoded Data</a>
</li>
<ul><li>8.1. <a href="#rfc.section.8.1">Foreword</a>
</li>
<li>8.2. <a href="#rfc.section.8.2">Implementation Requirements</a>
</li>
<li>8.3. <a href="#rfc.section.8.3">contentEncoding</a>
</li>
<li>8.4. <a href="#rfc.section.8.4">contentMediaType</a>
</li>
<li>8.5. <a href="#rfc.section.8.5">contentSchema</a>
</li>
<li>8.6. <a href="#rfc.section.8.6">Example</a>
</li>
</ul><li>9. <a href="#rfc.section.9">A Vocabulary for Basic Meta-Data Annotations</a>
</li>
<ul><li>9.1. <a href="#rfc.section.9.1">"title" and "description"</a>
</li>
<li>9.2. <a href="#rfc.section.9.2">"default"</a>
</li>
<li>9.3. <a href="#rfc.section.9.3">"deprecated"</a>
</li>
<li>9.4. <a href="#rfc.section.9.4">"readOnly" and "writeOnly"</a>
</li>
<li>9.5. <a href="#rfc.section.9.5">"examples"</a>
</li>
</ul><li>10. <a href="#rfc.section.10">Security Considerations</a>
</li>
<li>11. <a href="#rfc.references">References</a>
</li>
<ul><li>11.1. <a href="#rfc.references.1">Normative References</a>
</li>
<li>11.2. <a href="#rfc.references.2">Informative References</a>
</li>
</ul><li>Appendix A. <a href="#rfc.appendix.A">Keywords Moved from Validation to Core</a>
</li>
<li>Appendix B. <a href="#rfc.appendix.B">Acknowledgments</a>
</li>
<li>Appendix C. <a href="#rfc.appendix.C">ChangeLog</a>
</li>
<li><a href="#rfc.authors">Authors' Addresses</a>
</li>
</ul>
<h1 id="rfc.section.1">
<a href="#rfc.section.1">1.</a> Introduction</h1>
<p id="rfc.section.1.p.1">JSON Schema can be used to require that a given JSON document (an instance) satisfies a certain number of criteria. These criteria are asserted by using keywords described in this specification. In addition, a set of keywords is also defined to assist in interactive user interface instance generation. </p>
<p id="rfc.section.1.p.2">This specification will use the concepts, syntax, and terminology defined by the <a href="#json-schema" class="xref">JSON Schema core</a> specification. </p>
<h1 id="rfc.section.2">
<a href="#rfc.section.2">2.</a> Conventions and Terminology</h1>
<p id="rfc.section.2.p.1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in <a href="#RFC2119" class="xref">RFC 2119</a>. </p>
<p id="rfc.section.2.p.2">This specification uses the term "container instance" to refer to both array and object instances. It uses the term "children instances" to refer to array elements or object member values. </p>
<p id="rfc.section.2.p.3">Elements in an array value are said to be unique if no two elements of this array are <a href="#json-schema" class="xref">equal</a>. </p>
<h1 id="rfc.section.3">
<a href="#rfc.section.3">3.</a> Overview</h1>
<p id="rfc.section.3.p.1">JSON Schema validation asserts constraints on the structure of instance data. An instance location that satisfies all asserted constraints is then annotated with any keywords that contain non-assertion information, such as descriptive metadata and usage hints. If all locations within the instance satisfy all asserted constraints, then the instance is said to be valid against the schema. </p>
<p id="rfc.section.3.p.2">Each schema object is independently evaluated against each instance location to which it applies. This greatly simplifies the implementation requirements for validators by ensuring that they do not need to maintain state across the document-wide validation process. </p>
<p id="rfc.section.3.p.3">This specification defines a set of assertion keywords, as well as a small vocabulary of metadata keywords that can be used to annotate the JSON instance with useful information. The <a href="#format" class="xref">Section 7</a> keyword is intended primarily as an annotation, but can optionally be used as an assertion. The <a href="#content" class="xref">Section 8</a> keywords are annotations for working with documents embedded as JSON strings. </p>
<h1 id="rfc.section.4">
<a href="#rfc.section.4">4.</a> Interoperability Considerations</h1>
<h1 id="rfc.section.4.1">
<a href="#rfc.section.4.1">4.1.</a> Validation of String Instances</h1>
<p id="rfc.section.4.1.p.1">It should be noted that the nul character (\u0000) is valid in a JSON string. An instance to validate may contain a string value with this character, regardless of the ability of the underlying programming language to deal with such data. </p>
<h1 id="rfc.section.4.2">
<a href="#rfc.section.4.2">4.2.</a> Validation of Numeric Instances</h1>
<p id="rfc.section.4.2.p.1">The JSON specification allows numbers with arbitrary precision, and JSON Schema does not add any such bounds. This means that numeric instances processed by JSON Schema can be arbitrarily large and/or have an arbitrarily long decimal part, regardless of the ability of the underlying programming language to deal with such data. </p>
<h1 id="rfc.section.4.3">
<a href="#rfc.section.4.3">4.3.</a> <a href="#regexInterop" id="regexInterop">Regular Expressions</a>
</h1>
<p id="rfc.section.4.3.p.1">Keywords that use regular expressions, or constrain the instance value to be a regular expression, are subject to the interoperability considerations for regular expressions in the <a href="#json-schema" class="xref">JSON Schema Core</a> specification. </p>
<h1 id="rfc.section.5">
<a href="#rfc.section.5">5.</a> <a href="#meta-schema" id="meta-schema">Meta-Schema</a>
</h1>
<p id="rfc.section.5.p.1">The current URI for the default JSON Schema meta-schema is <span><</span><a href="http://json-schema.org/draft/2019-09/schema">http://json-schema.org/draft/2019-09/schema</a><span>></span>. For schema author convenience, this meta-schema describes all vocabularies defined in this specification and the JSON Schema Core specification, as well as two former keywords which are reserved for a transitional period. Individual vocabulary and vocabulary meta-schema URIs are given for each section below. Certain vocabularies are optional to support, which is explained in detail in the relevant sections. </p>
<p id="rfc.section.5.p.2">Updated vocabulary and meta-schema URIs MAY be published between specification drafts in order to correct errors. Implementations SHOULD consider URIs dated after this specification draft and before the next to indicate the same syntax and semantics as those listed here. </p>
<h1 id="rfc.section.6">
<a href="#rfc.section.6">6.</a> A Vocabulary for Structural Validation</h1>
<p id="rfc.section.6.p.1">Validation keywords in a schema impose requirements for successful validation of an instance. These keywords are all assertions without any annotation behavior. </p>
<p id="rfc.section.6.p.2">Meta-schemas that do not use "$vocabulary" SHOULD be considered to require this vocabulary as if its URI were present with a value of true. </p>
<p id="rfc.section.6.p.3">The current URI for this vocabulary, known as the Validation vocabulary, is: <span><</span><a href="https://json-schema.org/draft/2019-09/vocab/validation">https://json-schema.org/draft/2019-09/vocab/validation</a><span>></span>. </p>
<p id="rfc.section.6.p.4">The current URI for the corresponding meta-schema is: <span><</span><a href="https://json-schema.org/draft/2019-09/meta/validation">https://json-schema.org/draft/2019-09/meta/validation</a><span>></span>. </p>
<h1 id="rfc.section.6.1">
<a href="#rfc.section.6.1">6.1.</a> <a href="#general" id="general">Validation Keywords for Any Instance Type</a>
</h1>
<h1 id="rfc.section.6.1.1">
<a href="#rfc.section.6.1.1">6.1.1.</a> type</h1>
<p id="rfc.section.6.1.1.p.1">The value of this keyword MUST be either a string or an array. If it is an array, elements of the array MUST be strings and MUST be unique. </p>
<p id="rfc.section.6.1.1.p.2">String values MUST be one of the six primitive types ("null", "boolean", "object", "array", "number", or "string"), or "integer" which matches any number with a zero fractional part. </p>
<p id="rfc.section.6.1.1.p.3">An instance validates if and only if the instance is in any of the sets listed for this keyword. </p>
<h1 id="rfc.section.6.1.2">
<a href="#rfc.section.6.1.2">6.1.2.</a> <a href="#enum" id="enum">enum</a>
</h1>
<p id="rfc.section.6.1.2.p.1">The value of this keyword MUST be an array. This array SHOULD have at least one element. Elements in the array SHOULD be unique. </p>
<p id="rfc.section.6.1.2.p.2">An instance validates successfully against this keyword if its value is equal to one of the elements in this keyword's array value. </p>
<p id="rfc.section.6.1.2.p.3">Elements in the array might be of any type, including null. </p>
<h1 id="rfc.section.6.1.3">
<a href="#rfc.section.6.1.3">6.1.3.</a> const</h1>
<p id="rfc.section.6.1.3.p.1">The value of this keyword MAY be of any type, including null. </p>
<p id="rfc.section.6.1.3.p.2">Use of this keyword is functionally equivalent to an <a href="#enum" class="xref">"enum"</a> with a single value. </p>
<p id="rfc.section.6.1.3.p.3">An instance validates successfully against this keyword if its value is equal to the value of the keyword. </p>
<h1 id="rfc.section.6.2">
<a href="#rfc.section.6.2">6.2.</a> <a href="#numeric" id="numeric">Validation Keywords for Numeric Instances (number and integer)</a>
</h1>
<h1 id="rfc.section.6.2.1">
<a href="#rfc.section.6.2.1">6.2.1.</a> multipleOf</h1>
<p id="rfc.section.6.2.1.p.1">The value of "multipleOf" MUST be a number, strictly greater than 0. </p>
<p id="rfc.section.6.2.1.p.2">A numeric instance is valid only if division by this keyword's value results in an integer. </p>
<h1 id="rfc.section.6.2.2">
<a href="#rfc.section.6.2.2">6.2.2.</a> maximum</h1>
<p id="rfc.section.6.2.2.p.1">The value of "maximum" MUST be a number, representing an inclusive upper limit for a numeric instance. </p>
<p id="rfc.section.6.2.2.p.2">If the instance is a number, then this keyword validates only if the instance is less than or exactly equal to "maximum". </p>
<h1 id="rfc.section.6.2.3">
<a href="#rfc.section.6.2.3">6.2.3.</a> exclusiveMaximum</h1>
<p id="rfc.section.6.2.3.p.1">The value of "exclusiveMaximum" MUST be number, representing an exclusive upper limit for a numeric instance. </p>
<p id="rfc.section.6.2.3.p.2">If the instance is a number, then the instance is valid only if it has a value strictly less than (not equal to) "exclusiveMaximum". </p>
<h1 id="rfc.section.6.2.4">
<a href="#rfc.section.6.2.4">6.2.4.</a> minimum</h1>
<p id="rfc.section.6.2.4.p.1">The value of "minimum" MUST be a number, representing an inclusive lower limit for a numeric instance. </p>
<p id="rfc.section.6.2.4.p.2">If the instance is a number, then this keyword validates only if the instance is greater than or exactly equal to "minimum". </p>
<h1 id="rfc.section.6.2.5">
<a href="#rfc.section.6.2.5">6.2.5.</a> exclusiveMinimum</h1>
<p id="rfc.section.6.2.5.p.1">The value of "exclusiveMinimum" MUST be number, representing an exclusive lower limit for a numeric instance. </p>
<p id="rfc.section.6.2.5.p.2">If the instance is a number, then the instance is valid only if it has a value strictly greater than (not equal to) "exclusiveMinimum". </p>
<h1 id="rfc.section.6.3">
<a href="#rfc.section.6.3">6.3.</a> <a href="#string" id="string">Validation Keywords for Strings</a>
</h1>
<h1 id="rfc.section.6.3.1">
<a href="#rfc.section.6.3.1">6.3.1.</a> maxLength</h1>
<p id="rfc.section.6.3.1.p.1">The value of this keyword MUST be a non-negative integer.</p>
<p id="rfc.section.6.3.1.p.2">A string instance is valid against this keyword if its length is less than, or equal to, the value of this keyword. </p>
<p id="rfc.section.6.3.1.p.3">The length of a string instance is defined as the number of its characters as defined by <a href="#RFC8259" class="xref">RFC 8259</a>. </p>
<h1 id="rfc.section.6.3.2">
<a href="#rfc.section.6.3.2">6.3.2.</a> minLength</h1>
<p id="rfc.section.6.3.2.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.3.2.p.2">A string instance is valid against this keyword if its length is greater than, or equal to, the value of this keyword. </p>
<p id="rfc.section.6.3.2.p.3">The length of a string instance is defined as the number of its characters as defined by <a href="#RFC8259" class="xref">RFC 8259</a>. </p>
<p id="rfc.section.6.3.2.p.4">Omitting this keyword has the same behavior as a value of 0. </p>
<h1 id="rfc.section.6.3.3">
<a href="#rfc.section.6.3.3">6.3.3.</a> <a href="#pattern" id="pattern">pattern</a>
</h1>
<p id="rfc.section.6.3.3.p.1">The value of this keyword MUST be a string. This string SHOULD be a valid regular expression, according to the ECMA 262 regular expression dialect. </p>
<p id="rfc.section.6.3.3.p.2">A string instance is considered valid if the regular expression matches the instance successfully. Recall: regular expressions are not implicitly anchored. </p>
<h1 id="rfc.section.6.4">
<a href="#rfc.section.6.4">6.4.</a> Validation Keywords for Arrays</h1>
<h1 id="rfc.section.6.4.1">
<a href="#rfc.section.6.4.1">6.4.1.</a> maxItems</h1>
<p id="rfc.section.6.4.1.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.4.1.p.2">An array instance is valid against "maxItems" if its size is less than, or equal to, the value of this keyword. </p>
<h1 id="rfc.section.6.4.2">
<a href="#rfc.section.6.4.2">6.4.2.</a> minItems</h1>
<p id="rfc.section.6.4.2.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.4.2.p.2">An array instance is valid against "minItems" if its size is greater than, or equal to, the value of this keyword. </p>
<p id="rfc.section.6.4.2.p.3">Omitting this keyword has the same behavior as a value of 0. </p>
<h1 id="rfc.section.6.4.3">
<a href="#rfc.section.6.4.3">6.4.3.</a> uniqueItems</h1>
<p id="rfc.section.6.4.3.p.1">The value of this keyword MUST be a boolean. </p>
<p id="rfc.section.6.4.3.p.2">If this keyword has boolean value false, the instance validates successfully. If it has boolean value true, the instance validates successfully if all of its elements are unique. </p>
<p id="rfc.section.6.4.3.p.3">Omitting this keyword has the same behavior as a value of false. </p>
<h1 id="rfc.section.6.4.4">
<a href="#rfc.section.6.4.4">6.4.4.</a> maxContains</h1>
<p id="rfc.section.6.4.4.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.4.4.p.2">An array instance is valid against "maxContains" if the number of elements that are valid against the schema for <a href="#json-schema" class="xref">"contains"</a> is less than, or equal to, the value of this keyword. </p>
<p id="rfc.section.6.4.4.p.3">If "contains" is not present within the same schema object, then this keyword has no effect. </p>
<h1 id="rfc.section.6.4.5">
<a href="#rfc.section.6.4.5">6.4.5.</a> minContains</h1>
<p id="rfc.section.6.4.5.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.4.5.p.2">An array instance is valid against "minContains" if the number of elements that are valid against the schema for <a href="#json-schema" class="xref">"contains"</a> is greater than, or equal to, the value of this keyword. </p>
<p id="rfc.section.6.4.5.p.3">A value of 0 is allowed, but is only useful for setting a range of occurrences from 0 to the value of "maxContains". A value of 0 with no "maxContains" causes "contains" to always pass validation. </p>
<p id="rfc.section.6.4.5.p.4">If "contains" is not present within the same schema object, then this keyword has no effect. </p>
<p id="rfc.section.6.4.5.p.5">Omitting this keyword has the same behavior as a value of 1. </p>
<h1 id="rfc.section.6.5">
<a href="#rfc.section.6.5">6.5.</a> Validation Keywords for Objects</h1>
<h1 id="rfc.section.6.5.1">
<a href="#rfc.section.6.5.1">6.5.1.</a> maxProperties</h1>
<p id="rfc.section.6.5.1.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.5.1.p.2">An object instance is valid against "maxProperties" if its number of properties is less than, or equal to, the value of this keyword. </p>
<h1 id="rfc.section.6.5.2">
<a href="#rfc.section.6.5.2">6.5.2.</a> minProperties</h1>
<p id="rfc.section.6.5.2.p.1">The value of this keyword MUST be a non-negative integer. </p>
<p id="rfc.section.6.5.2.p.2">An object instance is valid against "minProperties" if its number of properties is greater than, or equal to, the value of this keyword. </p>
<p id="rfc.section.6.5.2.p.3">Omitting this keyword has the same behavior as a value of 0. </p>
<h1 id="rfc.section.6.5.3">
<a href="#rfc.section.6.5.3">6.5.3.</a> required</h1>
<p id="rfc.section.6.5.3.p.1">The value of this keyword MUST be an array. Elements of this array, if any, MUST be strings, and MUST be unique. </p>
<p id="rfc.section.6.5.3.p.2">An object instance is valid against this keyword if every item in the array is the name of a property in the instance. </p>
<p id="rfc.section.6.5.3.p.3">Omitting this keyword has the same behavior as an empty array. </p>
<h1 id="rfc.section.6.5.4">
<a href="#rfc.section.6.5.4">6.5.4.</a> dependentRequired</h1>
<p id="rfc.section.6.5.4.p.1">The value of this keyword MUST be an object. Properties in this object, if any, MUST be arrays. Elements in each array, if any, MUST be strings, and MUST be unique. </p>
<p id="rfc.section.6.5.4.p.2">This keyword specifies properties that are required if a specific other property is present. Their requirement is dependent on the presence of the other property. </p>
<p id="rfc.section.6.5.4.p.3">Validation succeeds if, for each name that appears in both the instance and as a name within this keyword's value, every item in the corresponding array is also the name of a property in the instance. </p>
<p id="rfc.section.6.5.4.p.4">Omitting this keyword has the same behavior as an empty object. </p>
<h1 id="rfc.section.7">
<a href="#rfc.section.7">7.</a> <a href="#format" id="format">A Vocabulary for Semantic Content With "format"</a>
</h1>
<h1 id="rfc.section.7.1">
<a href="#rfc.section.7.1">7.1.</a> Foreword</h1>
<p id="rfc.section.7.1.p.1">Structural validation alone may be insufficient to allow an application to correctly utilize certain values. The "format" annotation keyword is defined to allow schema authors to convey semantic information for a fixed subset of values which are accurately described by authoritative resources, be they RFCs or other external specifications. </p>
<p id="rfc.section.7.1.p.2">Implementations MAY treat "format" as an assertion in addition to an annotation, and attempt to validate the value's conformance to the specified semantics. See the Implementation Requirements below for details. </p>
<p id="rfc.section.7.1.p.3">The value of this keyword is called a format attribute. It MUST be a string. A format attribute can generally only validate a given set of instance types. If the type of the instance to validate is not in this set, validation for this format attribute and instance SHOULD succeed. All format attributes defined in this section apply to strings, but a format attribute can be specified to apply to any instance types defined in the data model defined in the <a href="#json-schema" class="xref">core JSON Schema.</a> <a id="CREF1" class="info">[CREF1]<span class="info">Note that the "type" keyword in this specification defines an "integer" type which is not part of the data model. Therefore a format attribute can be limited to numbers, but not specifically to integers. However, a numeric format can be used alongside the "type" keyword with a value of "integer", or could be explicitly defined to always pass if the number is not an integer, which produces essentially the same behavior as only applying to integers. </span></a> </p>
<p id="rfc.section.7.1.p.4">Meta-schemas that do not use "$vocabulary" SHOULD be considered to utilize this vocabulary as if its URI were present with a value of false. See the Implementation Requirements below for details. </p>
<p id="rfc.section.7.1.p.5">The current URI for this vocabulary, known as the Format vocabulary, is: <span><</span><a href="https://json-schema.org/draft/2019-09/vocab/format">https://json-schema.org/draft/2019-09/vocab/format</a><span>></span>. </p>
<p id="rfc.section.7.1.p.6">The current URI for the corresponding meta-schema is: <span><</span><a href="https://json-schema.org/draft/2019-09/meta/format">https://json-schema.org/draft/2019-09/meta/format</a><span>></span>. </p>
<h1 id="rfc.section.7.2">
<a href="#rfc.section.7.2">7.2.</a> Implementation Requirements</h1>
<p id="rfc.section.7.2.p.1">The "format" keyword functions as an annotation, and optionally as an assertion. <a id="CREF2" class="info">[CREF2]<span class="info">This is due to the keyword's history, and is not in line with current keyword design principles.</span></a> In order to manage this ambiguity, the "format" keyword is defined in its own separate vocabulary, as noted above. The true or false value of the vocabulary declaration governs the implementation requirements necessary to process a schema that uses "format", and the behaviors on which schema authors can rely. </p>
<h1 id="rfc.section.7.2.1">
<a href="#rfc.section.7.2.1">7.2.1.</a> As an annotation</h1>
<p id="rfc.section.7.2.1.p.1">The value of format MUST be collected as an annotation, if the implementation supports annotation collection. This enables application-level validation when schema validation is unavailable or inadequate. </p>
<p id="rfc.section.7.2.1.p.2">This requirement is not affected by the boolean value of the vocabulary declaration, nor by the configuration of "format"'s assertion behavior described in the next section. <a id="CREF3" class="info">[CREF3]<span class="info">Requiring annotation collection even when the vocabulary is declared with a value of false is atypical, but necessary to ensure that the best practice of performing application-level validation is possible even when assertion evaluation is not implemented. Since "format" has always been a part of this specification, requiring implementations to be aware of it even with a false vocabulary declaration is deemed to not be a burden. </span></a> </p>
<h1 id="rfc.section.7.2.2">
<a href="#rfc.section.7.2.2">7.2.2.</a> As an assertion</h1>
<p id="rfc.section.7.2.2.p.1">Regardless of the boolean value of the vocabulary declaration, an implementation that can evaluate "format" as an assertion MUST provide options to enable and disable such evaluation. The assertion evaluation behavior when the option is not explicitly specified depends on the vocabulary declaration's boolean value. </p>
<p id="rfc.section.7.2.2.p.2">When implementing this entire specification, this vocabulary MUST be supported with a value of false (but see details below), and MAY be supported with a value of true. </p>
<p id="rfc.section.7.2.2.p.3">When the vocabulary is declared with a value of false, an implementation: <a id="CREF4" class="info">[CREF4]<span class="info">This matches the current reality of implementations, which provide widely varying levels of validation, including no validation at all, for some or all format attributes. It is also designed to encourage relying only on the annotation behavior and performing semantic validation in the application, which is the recommended best practice. </span></a> </p>
<ul class="empty">
<li>MUST NOT evaluate "format" as an assertion unless it is explicitly configured to do so; </li>
<li>SHOULD provide an implementation-specific best effort validation for each format attribute defined below; </li>
<li>MAY choose to implement validation of any or all format attributes as a no-op by always producing a validation result of true; </li>
<li>SHOULD document its level of support for validation. </li>
</ul>
<p> </p>
<p id="rfc.section.7.2.2.p.4">When the vocabulary is declared with a value of true, an implementation that supports this form of the vocabulary: <a id="CREF5" class="info">[CREF5]<span class="info">The expectation is that for simple formats such as date-time, syntactic validation will be thorough. For a complex format such as email addresses, which are the amalgamation of various standards and numerous adjustments over time, with obscure and/or obsolete rules that may or may not be restricted by other applications making use of the value, a minimal validation is sufficient. For example, an instance string that does not contain an "@" is clearly not a valid email address, and an "email" or "hostname" containing characters outside of 7-bit ASCII is likewise clearly invalid. </span></a> </p>
<ul class="empty">
<li>MUST evaluate "format" as an assertion unless it is explicitly configured not to do so; </li>
<li>MUST implement syntactic validation for all format attributes defined in this specification, and for any additional format attributes that it recognizes, such that there exist possible instance values of the correct type that will fail validation. </li>
</ul>
<p> The requirement for minimal validation of format attributes is intentionally vague and permissive, due to the complexity involved in many of the attributes. Note in particular that the requirement is limited to syntactic checking; it is not to be expected that an implementation would send an email, attempt to connect to a URL, or otherwise check the existence of an entity identified by a format instance. </p>
<p id="rfc.section.7.2.2.p.5">It is RECOMMENDED that implementations use a common parsing library for each format, or a well-known regular expression. Implementations SHOULD clearly document how and to what degree each format attribute is validated. </p>
<p id="rfc.section.7.2.2.p.6">The <a href="#meta-schema" class="xref">standard core and validation meta-schema</a> includes this vocabulary in its "$vocabulary" keyword with a value of false, since by default implementations are not required to support this keyword as an assertion. Supporting the format vocabulary with a value of true is understood to greatly increase code size and in some cases execution time, and will not be appropriate for all implementations. </p>
<h1 id="rfc.section.7.2.3">
<a href="#rfc.section.7.2.3">7.2.3.</a> Custom format attributes</h1>
<p id="rfc.section.7.2.3.p.1">Implementations MAY support custom format attributes. Save for agreement between parties, schema authors SHALL NOT expect a peer implementation to support such custom format attributes. An implementation MUST NOT fail validation or cease processing due to an unknown format attribute. When treating "format" as an annotation, implementations SHOULD collect both known and unknown format attribute values. </p>
<p id="rfc.section.7.2.3.p.2">Vocabularies do not support specifically declaring different value sets for keywords. Due to this limitation, and the historically uneven implementation of this keyword, it is RECOMMENDED to define additional keywords in a custom vocabulary rather than additional format attributes if interoperability is desired. </p>
<h1 id="rfc.section.7.3">
<a href="#rfc.section.7.3">7.3.</a> Defined Formats</h1>
<h1 id="rfc.section.7.3.1">
<a href="#rfc.section.7.3.1">7.3.1.</a> Dates, Times, and Duration</h1>
<p id="rfc.section.7.3.1.p.1">These attributes apply to string instances. </p>
<p id="rfc.section.7.3.1.p.2">Date and time format names are derived from <a href="#RFC3339" class="xref">RFC 3339, section 5.6</a>. The duration format is from the ISO 8601 ABNF as given in Appendix A of RFC 3339. </p>
<p id="rfc.section.7.3.1.p.3">Implementations supporting formats SHOULD implement support for the following attributes: </p>
<dl>
<dt>date-time:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid representation according to the "date-time" production. </dd>
<dt>date:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid representation according to the "full-date" production. </dd>
<dt>time:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid representation according to the "full-time" production. </dd>
<dt>duration:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid representation according to the "duration" production. </dd>
</dl>
<p> </p>
<p id="rfc.section.7.3.1.p.4">Implementations MAY support additional attributes using the other production names defined in that section. If "full-date" or "full-time" are implemented, the corresponding short form ("date" or "time" respectively) MUST be implemented, and MUST behave identically. Implementations SHOULD NOT define extension attributes with any name matching an RFC 3339 production unless it validates according to the rules of that production. <a id="CREF6" class="info">[CREF6]<span class="info">There is not currently consensus on the need for supporting all RFC 3339 formats, so this approach of reserving the namespace will encourage experimentation without committing to the entire set. Either the format implementation requirements will become more flexible in general, or these will likely either be promoted to fully specified attributes or dropped. </span></a> </p>
<h1 id="rfc.section.7.3.2">
<a href="#rfc.section.7.3.2">7.3.2.</a> Email Addresses</h1>
<p id="rfc.section.7.3.2.p.1">These attributes apply to string instances. </p>
<p id="rfc.section.7.3.2.p.2">A string instance is valid against these attributes if it is a valid Internet email address as follows: </p>
<dl>
<dt>email:</dt>
<dd style="margin-left: 8">As defined by <a href="#RFC5322" class="xref">RFC 5322, section 3.4.1</a>. </dd>
<dt>idn-email:</dt>
<dd style="margin-left: 8">As defined by <a href="#RFC6531" class="xref">RFC 6531</a> </dd>
</dl>
<p> Note that all strings valid against the "email" attribute are also valid against the "idn-email" attribute. </p>
<h1 id="rfc.section.7.3.3">
<a href="#rfc.section.7.3.3">7.3.3.</a> Hostnames</h1>
<p id="rfc.section.7.3.3.p.1">These attributes apply to string instances. </p>
<p id="rfc.section.7.3.3.p.2">A string instance is valid against these attributes if it is a valid representation for an Internet hostname as follows: </p>
<dl>
<dt>hostname:</dt>
<dd style="margin-left: 8">As defined by <a href="#RFC1123" class="xref">RFC 1123, section 2.1</a>, including host names produced using the Punycode algorithm specified in <a href="#RFC5891" class="xref">RFC 5891, section 4.4</a>. </dd>
<dt>idn-hostname:</dt>
<dd style="margin-left: 8">As defined by either RFC 1123 as for hostname, or an internationalized hostname as defined by <a href="#RFC5890" class="xref">RFC 5890, section 2.3.2.3</a>. </dd>
</dl>
<p> Note that all strings valid against the "hostname" attribute are also valid against the "idn-hostname" attribute. </p>
<h1 id="rfc.section.7.3.4">
<a href="#rfc.section.7.3.4">7.3.4.</a> IP Addresses</h1>
<p id="rfc.section.7.3.4.p.1">These attributes apply to string instances. </p>
<p id="rfc.section.7.3.4.p.2">A string instance is valid against these attributes if it is a valid representation of an IP address as follows: </p>
<dl>
<dt>ipv4:</dt>
<dd style="margin-left: 8">An IPv4 address according to the "dotted-quad" ABNF syntax as defined in <a href="#RFC2673" class="xref">RFC 2673, section 3.2</a>. </dd>
<dt>ipv6:</dt>
<dd style="margin-left: 8">An IPv6 address as defined in <a href="#RFC4291" class="xref">RFC 4291, section 2.2</a>. </dd>
</dl>
<p> </p>
<h1 id="rfc.section.7.3.5">
<a href="#rfc.section.7.3.5">7.3.5.</a> Resource Identifiers</h1>
<p id="rfc.section.7.3.5.p.1">These attributes apply to string instances. </p>
<p></p>
<dl>
<dt>uri:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid URI, according to <a href="#RFC3986" class="xref">[RFC3986]</a>. </dd>
<dt>uri-reference:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid URI Reference (either a URI or a relative-reference), according to <a href="#RFC3986" class="xref">[RFC3986]</a>. </dd>
<dt>iri:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid IRI, according to <a href="#RFC3987" class="xref">[RFC3987]</a>. </dd>
<dt>iri-reference:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid IRI Reference (either an IRI or a relative-reference), according to <a href="#RFC3987" class="xref">[RFC3987]</a>. </dd>
<dt>uuid:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid string representation of a UUID, according to <a href="#RFC4122" class="xref">[RFC4122]</a>. </dd>
</dl>
<p> </p>
<p id="rfc.section.7.3.5.p.3">Note that all valid URIs are valid IRIs, and all valid URI References are also valid IRI References. </p>
<p id="rfc.section.7.3.5.p.4">Note also that the "uuid" format is for plain UUIDs, not UUIDs in URNs. An example is "f81d4fae-7dec-11d0-a765-00a0c91e6bf6". For UUIDs as URNs, use the "uri" format, with a "pattern" regular expression of "^urn:uuid:" to indicate the URI scheme and URN namespace. </p>
<h1 id="rfc.section.7.3.6">
<a href="#rfc.section.7.3.6">7.3.6.</a> uri-template</h1>
<p id="rfc.section.7.3.6.p.1">This attribute applies to string instances. </p>
<p id="rfc.section.7.3.6.p.2">A string instance is valid against this attribute if it is a valid URI Template (of any level), according to <a href="#RFC6570" class="xref">[RFC6570]</a>. </p>
<p id="rfc.section.7.3.6.p.3">Note that URI Templates may be used for IRIs; there is no separate IRI Template specification. </p>
<h1 id="rfc.section.7.3.7">
<a href="#rfc.section.7.3.7">7.3.7.</a> JSON Pointers</h1>
<p id="rfc.section.7.3.7.p.1">These attributes apply to string instances. </p>
<p></p>
<dl>
<dt>json-pointer:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid JSON string representation of a JSON Pointer, according to <a href="#RFC6901" class="xref">RFC 6901, section 5</a>. </dd>
<dt>relative-json-pointer:</dt>
<dd style="margin-left: 8">A string instance is valid against this attribute if it is a valid <a href="#relative-json-pointer" class="xref">Relative JSON Pointer</a>. </dd>
</dl>
<p> To allow for both absolute and relative JSON Pointers, use "anyOf" or "oneOf" to indicate support for either format. </p>
<h1 id="rfc.section.7.3.8">
<a href="#rfc.section.7.3.8">7.3.8.</a> regex</h1>
<p id="rfc.section.7.3.8.p.1">This attribute applies to string instances. </p>
<p id="rfc.section.7.3.8.p.2">A regular expression, which SHOULD be valid according to the <a href="#ecma262" class="xref">ECMA 262</a> regular expression dialect. </p>
<p id="rfc.section.7.3.8.p.3">Implementations that validate formats MUST accept at least the subset of ECMA 262 defined in the <a href="#regexInterop" class="xref">Regular Expressions</a> section of this specification, and SHOULD accept all valid ECMA 262 expressions. </p>
<h1 id="rfc.section.8">
<a href="#rfc.section.8">8.</a> <a href="#content" id="content">A Vocabulary for the Contents of String-Encoded Data</a>
</h1>
<h1 id="rfc.section.8.1">
<a href="#rfc.section.8.1">8.1.</a> Foreword</h1>
<p id="rfc.section.8.1.p.1">Annotations defined in this section indicate that an instance contains non-JSON data encoded in a JSON string. </p>
<p id="rfc.section.8.1.p.2">These properties provide additional information required to interpret JSON data as rich multimedia documents. They describe the type of content, how it is encoded, and/or how it may be validated. They do not function as validation assertions; a malformed string-encoded document MUST NOT cause the containing instance to be considered invalid. </p>
<p id="rfc.section.8.1.p.3">Meta-schemas that do not use "$vocabulary" SHOULD be considered to require this vocabulary as if its URI were present with a value of true. </p>
<p id="rfc.section.8.1.p.4">The current URI for this vocabulary, known as the Content vocabulary, is: <span><</span><a href="https://json-schema.org/draft/2019-09/vocab/content">https://json-schema.org/draft/2019-09/vocab/content</a><span>></span>. </p>
<p id="rfc.section.8.1.p.5">The current URI for the corresponding meta-schema is: <span><</span><a href="https://json-schema.org/draft/2019-09/meta/content">https://json-schema.org/draft/2019-09/meta/content</a><span>></span>. </p>
<h1 id="rfc.section.8.2">
<a href="#rfc.section.8.2">8.2.</a> Implementation Requirements</h1>
<p id="rfc.section.8.2.p.1">Due to security and performance concerns, as well as the open-ended nature of possible content types, implementations MUST NOT automatically decode, parse, and/or validate the string contents by default. This additionally supports the use case of embedded documents intended for processing by a different consumer than that which processed the containing document. </p>
<p id="rfc.section.8.2.p.2">All keywords in this section apply only to strings, and have no effect on other data types. </p>
<p id="rfc.section.8.2.p.3">Implementations MAY offer the ability to decode, parse, and/or validate the string contents automatically. However, it MUST NOT perform these operations by default, and MUST provide the validation result of each string-encoded document separately from the enclosing document. This process SHOULD be equivalent to fully evaluating the instance against the original schema, followed by using the annotations to decode, parse, and/or validate each string-encoded document. <a id="CREF7" class="info">[CREF7]<span class="info">For now, the exact mechanism of performing and returning parsed data and/or validation results from such an automatic decoding, parsing, and validating feature is left unspecified. Should such a feature prove popular, it may be specified more thoroughly in a future draft. </span></a> </p>
<p id="rfc.section.8.2.p.4">See also the <a href="#security" class="xref">Security Considerations</a> sections for possible vulnerabilities introduced by automatically processing the instance string according to these keywords. </p>
<h1 id="rfc.section.8.3">
<a href="#rfc.section.8.3">8.3.</a> contentEncoding</h1>
<p id="rfc.section.8.3.p.1">If the instance value is a string, this property defines that the string SHOULD be interpreted as binary data and decoded using the encoding named by this property. </p>
<p id="rfc.section.8.3.p.2">Possible values for this property are listed in <a href="#RFC2045" class="xref">RFC 2045, Sec 6.1</a> and <a href="#RFC4648" class="xref">RFC 4648</a>. For "base64", which is defined in both RFCs, the definition in RFC 4648, which removes line length limitations, SHOULD be used, as various other specifications have mandated different lengths. Note that line lengths within a string can be constrained using the <a href="#pattern" class="xref">"pattern"</a> keyword. </p>
<p id="rfc.section.8.3.p.3">If this keyword is absent, but "contentMediaType" is present, this indicates that the media type could be encoded into UTF-8 like any other JSON string value, and does not require additional decoding. </p>
<p id="rfc.section.8.3.p.4">The value of this property MUST be a string. </p>
<h1 id="rfc.section.8.4">
<a href="#rfc.section.8.4">8.4.</a> contentMediaType</h1>
<p id="rfc.section.8.4.p.1">If the instance is a string, this property indicates the media type of the contents of the string. If "contentEncoding" is present, this property describes the decoded string. </p>
<p id="rfc.section.8.4.p.2">The value of this property MUST be a string, which MUST be a media type, as defined by <a href="#RFC2046" class="xref">RFC 2046</a>. </p>
<h1 id="rfc.section.8.5">
<a href="#rfc.section.8.5">8.5.</a> contentSchema</h1>
<p id="rfc.section.8.5.p.1">If the instance is a string, and if "contentMediaType" is present, this property contains a schema which describes the structure of the string. </p>
<p id="rfc.section.8.5.p.2">This keyword MAY be used with any media type that can be mapped into JSON Schema's data model. </p>
<p id="rfc.section.8.5.p.3">The value of this property SHOULD be ignored if "contentMediaType" is not present. </p>
<h1 id="rfc.section.8.6">
<a href="#rfc.section.8.6">8.6.</a> Example</h1>
<p>Here is an example schema, illustrating the use of "contentEncoding" and "contentMediaType": </p>
<pre>
{
"type": "string",