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Version 4.0.x is a complete redesign of the underlying setup, but tries to be API compatible or similar to 3.x UuidValue is still Experimental and the API for it is in flux, please pay attention to changelogs and versions.

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uuid

Simple, fast generation of RFC4122 UUIDs.

Features:

• Generate RFC4122 version 1, version 4, or version 5 UUIDs
• Runs in web, server, and flutter
• Cryptographically strong random number generation on all platforms
  • Defaults to non-crypto generator, see UuidUtil for cryptoRNG
• Documentation

Getting Started

Instructions

1. Open a command line and cd to your projects root folder
2. In your pubspec, add an entry for dart-uuid to your dependencies (example below)
3. pub install
4. If you wish to run tests, go into packages/dart-uuid/ and run 'dart test/uuid_test.dart'

Pubspec

There are 2 options. Directly from git, or from pub.dartlang.org

pub.dartlang.org: (you can use 'any' instead of a version if you just want the latest always)

dependencies:
  uuid: 4.0.0-beta1

import 'package:uuid/uuid.dart';

var uuid = Uuid();

Then create some ids ...

// Generate a v1 (time-based) id
uuid.v1(); // -> '6c84fb90-12c4-11e1-840d-7b25c5ee775a'

// Generate a v4 (random) id
uuid.v4(); // -> '110ec58a-a0f2-4ac4-8393-c866d813b8d1'

// Generate a v5 (namespace-name-sha1-based) id
uuid.v5(Uuid.NAMESPACE_URL, 'www.google.com'); // -> 'c74a196f-f19d-5ea9-bffd-a2742432fc9c'

API

Uuid({Map<String, dynamic> options: null}) -> Uuid (Constructor)

Constructor supports setting some global RNG sertings so you don't have to specify them on each function call for v4 or v5

• options - (Map<String, dynamic>) Optional uuid state to apply. Properties may include:

  • grng - (Function) Random # generator to use as a global rng function. A Custom function that returns an list[16] of byte values or 1 of 2 provided.
  • gNamedArgs - (Map<Symbol, dynamic>) The arguments and values you want to pass to your global rng function.
  • gPositionalArgs - (List) The positional arguments for your global rng functions, if any.
  • v1rng - (Function) Random # generator to use as a rng function for v1 seed. A Custom function that returns an list[16] of byte values or 1 of 2 provided.
  • v1rngNamedArgs - (Map<Symbol, dynamic>) The arguments and values you want to pass to your v1 rng function.
  • v1rngPositionalArgs - (List) The positional arguments for your v1 rng functions, if any.

Defaults are Uuid.mathRNG

Example: Using CryptoRNG globally

var uuid = Uuid(options: {
  'grng': UuidUtil.cryptoRNG
})

// Generate a v4 (random) id that will use cryptRNG for its rng function
uuid.v4();

uuid.v1({Map<String, dynamic> options: null) -> String

uuid.v1obj({Map<String, dynamic> options: null) -> UuidValue

uuid.v1buffer(List buffer, {Map<String, dynamic> options: null, int offset: 0}) -> List

Generate and return a RFC4122 v1 (timestamp-based) UUID.

• options - (Map<String, dynamic>) Optional uuid state to apply. Properties may include:

  • node - (List) Node id as List of 6 bytes (per 4.1.6). Default: Randomnly generated ID.
  • clockseq - (Number between 0 - 0x3fff) RFC clock sequence. Default: An internally maintained clockseq is used.
  • msecs - (Number) Time in milliseconds since unix Epoch. Default: The current time is used.
  • nsecs - (Number between 0-9999) additional time, in 100-nanosecond units. Ignored if msecs is unspecified. Default: internal uuid counter is used, as per 4.2.1.2.

• buffer - (List) Array or buffer where UUID bytes are to be written.

• offset - (Int) Starting index in buffer at which to begin writing.

v1() returns a string representation of the uuid.

v1buffer() Returns a List buffer, if specified, also writes the data to the provided buffer.

v1obj() Returns a UuidValue, which has a validation check and some internal functions wrapping the string.

Example: Generate string UUID with fully-specified options

uuid.v1(options: {
    'node': [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
    'clockSeq': 0x1234,
    'mSecs': new DateTime.utc(2011,11,01).millisecondsSinceEpoch,
    'nSecs': 5678
})   // -> "710b962e-041c-11e1-9234-0123456789ab"

Example: In-place generation of two binary IDs

// Generate two ids in an array
var myBuffer = new List(32); // -> []
uuid.v1buffer(myBuffer);
// -> [115, 189, 5, 128, 201, 91, 17, 225, 146, 52, 109, 0, 9, 0, 52, 128, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null]
uuid.v1buffer(myBuffer, offset: 16);  
// -> [115, 189, 5, 128, 201, 91, 17, 225, 146, 52, 109, 0, 9, 0, 52, 128, 115, 189, 5, 129, 201, 91, 17, 225, 146, 52, 109, 0, 9, 0, 52, 128]

// Optionally use uuid.unparse() to get stringify the ids
uuid.unparse(myBuffer);    // -> '73bd0580-c95b-11e1-9234-6d0009003480'
uuid.unparse(myBuffer, offset: 16) // -> '73bd0581-c95b-11e1-9234-6d0009003480'

Example: UuidValue usage

uuidValue = uuid.v1Obj(options: {
    'node': [0x01, 0x23, 0x45, 0x67, 0x89, 0xab],
    'clockSeq': 0x1234,
    'mSecs': new DateTime.utc(2011,11,01).millisecondsSinceEpoch,
    'nSecs': 5678
}) // -> UuidValue{uuid: '710b962e-041c-11e1-9234-0123456789ab'}

print(uuidValue) -> // -> '710b962e-041c-11e1-9234-0123456789ab'
uuidValue.toBytes() -> // -> [...]

uuid.v4({Map<String, dynamic> options: null}) -> String

uuid.v4obj({Map<String, dynamic> options: null}) -> UuidValue

uuid.v4buffer(List buffer, {Map<String, dynamic> options: null, int offset: 0}) -> List

Generate and return a RFC4122 v4 UUID.

• options - (Map<String, dynamic>) Optional uuid state to apply. Properties may include:

  • random - (Number[16]) List of 16 numbers (0-255) to use in place of randomly generated values
  • rng - (Function) Random # generator to use. A Custom function that returns an list[16] of byte values or 1 of 2 provided.
  • namedArgs - (Map<Symbol, dynamic>) The arguments and values you want to pass to your function.
  • positionalArgs - (List) The positional arguments for your functions. if any.

• buffer - (List) Array or buffer where UUID bytes are to be written.

• offset - (Number) Starting index in buffer at which to begin writing.

v4() returns a string representation of the uuid.

v4buffer() Returns a List buffer, if specified, also writes the data to the provided buffer.

v4obj() Returns a UuidValue, which has a validation check and some internal functions wrapping the string.

Example: Generate string UUID with different RNG method

import 'package:uuid/uuid_util.dart';
uuid.v4(options: {
  'rng': UuidUtil.cryptoRNG
});
// -> "109156be-c4fb-41ea-b1b4-efe1671c5836"

Example: Generate string UUID with different RNG method and named parameters

import 'package:uuid/uuid_util.dart';
uuid.v4(options: {
  'rng': UuidUtil.mathRNG,
  'namedArgs': new Map.fromIterables([const Symbol('seed')],[1])
});
// -> "09a91894-e93f-4141-a3ec-82eb32f2a3ef"

Example: Generate string UUID with different RNG method and positional parameters

import 'package:uuid/uuid_util.dart';
uuid.v4(options: {
  'rng': UuidUtil.cryptoRNG,
  'positionalArgs': [1]
});
// -> "09a91894-e93f-4141-a3ec-82eb32f2a3ef"

Example: Generate string UUID with fully-specified options

uuid.v4(options: {
  'random': [
    0x10, 0x91, 0x56, 0xbe, 0xc4, 0xfb, 0xc1, 0xea,
    0x71, 0xb4, 0xef, 0xe1, 0x67, 0x1c, 0x58, 0x36
  ]
});
// -> "109156be-c4fb-41ea-b1b4-efe1671c5836"

Example: Generate two IDs in a single buffer

var myBuffer = new List(32);
uuid.v4buffer(myBuffer);
uuid.v4buffer(myBuffer, offset: 16);

Example: UuidValue usage

uuidValue = uuid.v4obj(options: {
  'random': [
    0x10, 0x91, 0x56, 0xbe, 0xc4, 0xfb, 0xc1, 0xea,
    0x71, 0xb4, 0xef, 0xe1, 0x67, 0x1c, 0x58, 0x36
  ]
}) // -> UuidValue{uuid: '109156be-c4fb-41ea-b1b4-efe1671c5836'}

print(uuidValue) -> // -> '109156be-c4fb-41ea-b1b4-efe1671c5836'
uuidValue.toBytes() -> // -> [...]

uuid.v5(String namespace, String name, {Map<String, dynamic> options: null}) -> String

uuid.v5obj(String namespace, String name, {Map<String, dynamic> options: null}) -> UuidValue

uuid.v5buffer(String namespace, String name, List buffer, {Map<String, dynamic> options: null, int offset: 0}) -> List

Generate and return a RFC4122 v5 UUID.

• options - (Map<String, dynamic>) Optional uuid state to apply. Properties may include:

  • randomNamespace - (Boolean) Default True. Returns if you want a v4 generated namespace (true) or NAMESPACE_NIL (false)

• buffer - (List) Array or buffer where UUID bytes are to be written.

• offset - (Number) Starting index in buffer at which to begin writing.

v5() returns a string representation of the uuid.

v5buffer() Returns a List buffer, if specified, also writes the data to the provided buffer.

v5obj() Returns a UuidValue, which has a validation check and some internal functions wrapping the string.

Example: Generate string UUID with fully-specified options

uuid.v5(Uuid.NAMESPACE_URL, 'www.google.com');
// -> "c74a196f-f19d-5ea9-bffd-a2742432fc9c"

Example: Generate two IDs in a single buffer

var myBuffer = new List(32);
uuid.v5buffer(Uuid.NAMESPACE_URL, 'www.google.com', myBuffer);
uuid.v5buffer(Uuid.NAMESPACE_URL, 'www.google.com', myBuffer, offset: 16);

Example: UuidValue usage

uuidValue = uuid.v5obj(Uuid.NAMESPACE_URL, 'www.google.com'); 
// -> UuidValue(uuid: "c74a196f-f19d-5ea9-bffd-a2742432fc9c")

print(uuidValue) -> // -> 'c74a196f-f19d-5ea9-bffd-a2742432fc9c'
uuidValue.toBytes() -> // -> [...]

uuid.parse(String uuid, {List buffer: null, int offset: 0, bool validate: true, ValidationMode validationMode: ValidationMode.strictRFC4122}) -> List

uuid.parseAsByteList(String uuid, {List buffer: null, int offset: 0, bool validate: true, ValidationMode validationMode: ValidationMode.strictRFC4122}) -> Uint8List

uuid.unparse(List buffer, {int offset: 0}) -> String

Parse and unparse UUIDs

• id - (String) UUID(-like) string
• buffer - (List) Array or buffer where UUID bytes are to be written. Default: A new Array or Buffer is used
• offset - (Int | Number) Starting index in buffer at which to begin writing. Default: 0
• validate - (bool, default: true) Allows you to disable UUID validation, mostly useful for Microsoft GUID nonsense.

Throws: parse() -> FormatException - when not a valid UUID unparse() -> Exception - when length of list contents is not 16

Example parsing and unparsing a UUID string

var bytes = uuid.parse('797ff043-11eb-11e1-80d6-510998755d10'); // -> [121, 127, 240, 67, 17, 235, 17, 225, 128, 214, 81, 9, 152, 117, 93, 16]
var string = uuid.unparse(bytes); // -> '797ff043-11eb-11e1-80d6-510998755d10'

For more examples or usage, check my test implementations.

Testing

In dartvm

dart test\uuid_test.dart

In Browser/flutter

No in browser testing, but I know many use it in Web and Flutter projects.

Dart2js output size (minified, optimized with -O2)

• v1 only: 59kb

• v4 only: 54kb

• v4 crypto only: 61kb

• v5 only: 69kb

• v1 + v4: 66kb (includes crypto)

• v4 + v5: 76kb (includes crypto)

• ALL: 76kb

• v1 + v5: 77kb

Release notes

See CHANGELOG