How to check if variable contains valid UUID/GUID identifier?
I'm currently interested only in validating types 1 and 4, but it should not be a limitation to your answers.
331
votes
in string format, not hex, not bin, or I don't know what do you ask for
– Marek Sebera
^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$
– Brandon Moretz
If you cannot exclude variables containing a chain of 32 consecutive hex digits (without grouping), have a look at my answer
– Wolf
Might be helpful: npmjs.com/package/uuid-validate
– Ben
12 Answers
498
votes
Currently, UUID's are as specified in RFC4122. An often neglected edge case is the NIL UUID, noted here. The following regex takes this into account and will return a match for a NIL UUID. See below for a UUID which only accepts non-NIL UUIDs. Both of these solutions are for versions 1 to 5 (see the first character of the third block).
Therefore to validate a UUID...
/^[0-9a-f]{8}-[0-9a-f]{4}-[0-5][0-9a-f]{3}-[089ab][0-9a-f]{3}-[0-9a-f]{12}$/i
...ensures you have a canonically formatted UUID that is Version 1 through 5 and is the appropriate Variant as per RFC4122.
NOTE: Braces { and } are not canonical. They are an artifact of some systems and usages.
Easy to modify the above regex to meet the requirements of the original question.
HINT: regex group/captures
To avoid matching NIL UUID:
/^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
73
votes
62
votes
If you want to check or validate a specific UUID version, here are the corresponding regexes.
Note that the only difference is the version number, which is explained in
4.1.3. Versionchapter of UUID 4122 RFC.
The version number is the first character of the third group : [VERSION_NUMBER][0-9A-F]{3} :
UUID v1 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[1][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/iUUID v2 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[2][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/iUUID v3 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[3][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/iUUID v4 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[4][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/iUUID v5 :
/^[0-9A-F]{8}-[0-9A-F]{4}-[5][0-9A-F]{3}-[89AB][0-9A-F]{3}-[0-9A-F]{12}$/i
44
votes
If you are using Node.js for development, it is recommended to use a package called Validator. It includes all the regexes required to validate different versions of UUID's plus you get various other functions for validation.
Here is the npm link: Validator
var a = 'd3aa88e2-c754-41e0-8ba6-4198a34aa0a2'
v.isUUID(a)
true
v.isUUID('abc')
false
v.isNull(a)
false
19
votes
14
votes
Beside Gambol's answer that will do the job in nearly all cases, all answers given so far missed that the grouped formatting (8-4-4-4-12) is not mandatory to encode GUIDs in text. It's used extremely often but obviously also a plain chain of 32 hexadecimal digits can be valid.[1]regexenh:
/^[0-9a-f]{8}-?[0-9a-f]{4}-?[1-5][0-9a-f]{3}-?[89ab][0-9a-f]{3}-?[0-9a-f]{12}$/i
[1] The question is about checking variables, so we should include the user-unfriendly form as well.
10
votes
All type-specific regexes posted so far are failing on the "type 0" Nil UUID, defined in 4.1.7 of the RFC as:
The nil UUID is special form of UUID that is specified to have all 128 bits set to zero:
00000000-0000-0000-0000-000000000000
To modify Wolf's answer:
/^[0-9a-f]{8}-?[0-9a-f]{4}-?[0-5][0-9a-f]{3}-?[089ab][0-9a-f]{3}-?[0-9a-f]{12}$/i
Or, to properly exclude a "type 0" without all zeros, we have the following (thanks to Luke):
/^(?:[0-9a-f]{8}-?[0-9a-f]{4}-?[1-5][0-9a-f]{3}-?[89ab][0-9a-f]{3}-?[0-9a-f]{12}|00000000-0000-0000-0000-000000000000)$/i
3
votes
I think Gambol's answer is almost perfect, but it misinterprets the RFC 4122 § 4.1.1. Variant section a bit.
It covers Variant-1 UUIDs (10xx = 8..b), but does not cover Variant-0 (0xxx = 0..7) and Variant-2 (110x = c..d) variants which are reserved for backward compatibility, so they are technically valid UUIDs. Variant-4 (111x = e..f) is indeed reserved for future use, so they are not valid currently.
Also, 0 type is not valid, that "digit" is only allowed to be 0 if it's a NIL UUID (like mentioned in Evan's answer).
So I think the most accurate regex that complies with current RFC 4122 specification is (including hyphens):
/^([0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[0-9a-d][0-9a-f]{3}-[0-9a-f]{12}|00000000-0000-0000-0000-000000000000)$/i
^ ^^^^^^
(0 type is not valid) (only e..f variant digit is invalid currently)
2
votes
A slightly modified version of the above answers written in a more concise way. This will validate any GUID with hyphens (however easily modified to make hyphens optional). This will also support upper and lower case characters which has become the convention regardless of the specification:
/^([0-9a-fA-F]{8})-(([0-9a-fA-F]{4}\-){3})([0-9a-fA-F]{12})$/i
The key here is the repeating part below
(([0-9a-fA-F]{4}\-){3})
Which simply repeats the 4 char patterns 3 times
1
votes
1
votes
A good way to do it in Node is to use the ajv package (https://github.com/epoberezkin/ajv).
const Ajv = require('ajv');
const ajv = new Ajv({ allErrors: true, useDefaults: true, verbose: true });
const uuidSchema = { type: 'string', format: 'uuid' };
ajv.validate(uuidSchema, 'bogus'); // returns false
ajv.validate(uuidSchema, 'd42a8273-a4fe-4eb2-b4ee-c1fc57eb9865'); // returns true with v4 GUID
ajv.validate(uuidSchema, '892717ce-3bd8-11ea-b77f-2e728ce88125'); // returns true with a v1 GUID
-1
votes
I think a better way is using the static method fromString to avoid those regular expressions.
id = UUID.randomUUID();
UUID uuid = UUID.fromString(id.toString());
Assert.assertEquals(id.toString(), uuid.toString());
On the other hand
UUID uuidFalse = UUID.fromString("x");
throws java.lang.IllegalArgumentException: Invalid UUID string: x
