CODEWITHSUNDEEP
go
Roberto Santelices
Roberto Santelices

Reputation: 363

How to validate UUID v4 in Go?

I have the following piece of code:

func GetUUIDValidator(text string) bool {
    r, _ := regexp.Compile("/[a-f0-9]{8}-[a-f0-9]{4}-4[a-f0-9]{3}-[89aAbB][a-f0-9]{3}-[a-f0-9]{12}/")
    return r.Match([]byte(text))
}

But when I pass fbd3036f-0f1c-4e98-b71c-d4cd61213f90 as a value, I got false, while indeed it is an UUID v4.

What am I doing wrong?

Upvotes: 36

Views: 60655

Answers (5)

mattes
mattes

Reputation: 9429

Regex is expensive. The following approach is ~18x times faster than the regex version.

Use something like https://godoc.org/github.com/google/uuid#Validate instead.

import "github.com/google/uuid"

if err := uuid.Validate("uuid..."); err == nil {
  // valid UUID
}

[Jan 2025] Updated to use Validate instead of Parse, which was added in v1.5.0.

Upvotes: 110

Kevin
Kevin

Reputation: 1240

Since Dec 12, 2023 there is a new feature to validate directly by string: https://github.com/google/uuid/commit/9ee7366e66c9ad96bab89139418a713dc584ae29

var string anyUUID = "elmo"
err := uuid.Validate(anyUUID) // will result in an error

Live example: https://go.dev/play/p/QIzW63S0Oda

This is very useful when it comes to testing:

assert.NoError(t, uuid.Validate(anyUUID))

Upvotes: 0

OscarHanzely
OscarHanzely

Reputation: 114

In case you would be validating it as attribute of a struct, there is an awesome golang library straight from the Go called validator https://godoc.org/gopkg.in/go-playground/validator.v9 which you can use to validate all kinds of fields nested structures by provided built-in validators as well as complete custom validation methods. All you need to do is just add proper tags to the fields

import "gopkg.in/go-playground/validator.v9"

type myObject struct {
    UID string `validate:"required,uuid4"`
}

func validate(obj *myObject) {
    validate := validator.New()
    err := validate.Struct(obj)
}

It provides structured field errors and other relevant data from it.

Upvotes: 5

Patrick D'appollonio
Patrick D'appollonio

Reputation: 2762

Try with...

func IsValidUUID(uuid string) bool {
    r := regexp.MustCompile("^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-4[a-fA-F0-9]{3}-[8|9|aA|bB][a-fA-F0-9]{3}-[a-fA-F0-9]{12}$")
    return r.MatchString(uuid)
}

Live example: https://play.golang.org/p/a4Z-Jn4EvG

Note: as others have said, validating UUIDs with regular expressions can be slow. Consider other options too if you need better performance.

Upvotes: 49

rudresh4
rudresh4

Reputation: 141

You can utilize satori/go.uuid package to accomplish this:

import "github.com/satori/go.uuid"

func IsValidUUID(u string) bool {
  _, err := uuid.FromString(u)
  return err == nil
}

This package is widely used for UUID operations: https://github.com/satori/go.uuid

Upvotes: 9

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