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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: 3.0.0-nullsafety.0
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 list16 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 list16 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 = new 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.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.

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'

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

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

Generate and return a RFC4122 v4 UUID.

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

    • random - (Number16) 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 list16 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.

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);

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

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

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.

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);

uuid.parse(String uuid, {List buffer: null, int offset: 0})

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

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

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: 56kb

  • v4 only: 54kb

  • v4 crypto only: 55kb

  • v5 only: 67kb

  • v1 + v4: 59kb (includes crypto)

  • v4 + v5: 68kb (includes crypto)

  • ALL: 72kb

  • v1 + v5: 70kb

Release notes

See CHANGELOG

Libraries

uuid
Generates UUID v1, v4, v5 following RFC4122 standard.
uuid_util
Utility functions for UUID library.