How can I know if a UUID/GUID is valid?

Problem

How can I tell if a variable includes a valid UUID/GUID?

I’m currently only interested in validating kinds 1 and 4, but this should not limit your responses.

Asked by Marek Sebera

Solution #1

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).

As a result, validating 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 an RFC4122-compliant canonically formatted UUID that is Version 1 through 5 and the proper Variant.

Braces and are not canonical terms. They are a byproduct of certain systems and applications.

It’s simple to adapt the above regex to fit the original question’s requirements.

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

Answered by Gambol

Solution #2

regex saves the day

/^[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}$/.test('01234567-9ABC-DEF0-1234-56789ABCDEF0');

or with brackets

/^\{?[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}‌​\}?$/

Answered by ryanb

Solution #3

Here are the corresponding regexes for checking or validating a certain UUID version.

The first character of the third group represents the version number: [VERSION NUMBER][0-9A-F]3: [VERSION NUMBER][0-9A-F]3:

Answered by Ivan Gabriele

Solution #4

Validator is a package that is recommended if you are using Node.js for development. It comes with all of the regexes needed to validate various versions of UUIDs, as well as a variety of other validation methods.

The npm link is here: Validator

var a = 'd3aa88e2-c754-41e0-8ba6-4198a34aa0a2'
v.isUUID(a)
true
v.isUUID('abc')
false
v.isNull(a)
false

Answered by Neeraj Sharma

Solution #5

with some changes thanks to @usertatha

function isUUID ( uuid ) {
    let s = "" + uuid;

    s = s.match('^[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}$');
    if (s === null) {
      return false;
    }
    return true;
}

Answered by Souhaieb

Post is based on https://stackoverflow.com/questions/7905929/how-to-test-valid-uuid-guid