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Library to generate DB-friendly GUIDs

0.1.3 2017-08-30 10:14 UTC

This package is auto-updated.

Last update: 2024-01-07 19:38:46 UTC


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The Unicity library serves to the purpose of generating globally unique IDs ensuring some properties:

  • High (but controllable) degree of entropy/randomness:
    • Required to avoid ID guessing attacks.
  • Time-related ID (with controllable precision, and proper internal representation):
    • Time-related IDs (using a proper internal representation: Big-Endian) are a good helper to preserve the natural order of insertion in our DBs.
    • In addition, using time-related IDs allows us to use B-Tree indexes without having to recreate the index with almost every insertion due to randomness.
  • The possibility of representing the ID using multiple formats, including compact binary strings:
    • Base64
    • Base64 with an adaptation to be used in URLs
    • Hexadecimal
    • Binary string (the most compact form, ideal to ensure small DB indexes)


Install it through composer, that's it:

composer require unicity/unicity

Code examples

The Factory


use Unicity\GUIDFactory;

// A good place to start is to instantiate a factory that will help us to create
// or to unserialize GUIDs following the specified constraints.

// The first parameter tells us how many timestamp-related bytes we want to use
//   (from 4 to 7 bytes, by default 7)
// The second parameter tells us how many randomness bytes we want to use
//   (from 2 to 9 bytes, by default 9)
$guidFactory = new \Unicity\GUIDFactory(5, 7);

An important point to take into account is that, for testing and dependency injection purposes, you should type hint using the Unicity\Interfaces\GUIDFactory interface.

The same point applies to GUID instances, its better to type hint using the Unicity\Interfaces\GUID interface.

Creating new GUID instances


// This will create a completely new GUID following the constraints specified in the factory constructor
$newGUID = $guidFactory->create();

Unserializing GUIDs


// This will unserialize (and validate) a GUID from an hexadecimal string
$recoveredGUID = $guidFactory->fromHexString('1234567890ab1234567890ab');

// This will unserialize (and validate) a GUID from a base64 string
$recoveredGUID = $guidFactory->fromBase64String('EjRWeJCrEjRWeJCr');

// This will unserialize (and validate) a GUID from a base64 (modified for URLs) string
$recoveredGUID = $guidFactory->fromBase64UrlString('EjRWeJCrEjRWeJCr');

// This will unserialize (and validate) a GUID from a binary bytes stream
$recoveredGUID = $guidFactory->fromBinaryString('1234567890ab');

Serializing GUIDs


$hexString = $newGUID->asHexString();
$base64String = $newGUID->asBase64String();
$base64urlString = $newGUID->asBase64UrlString();
$bytesStream = $newGUID->asBinaryString();

Comparing GUIDs


if (!$requestGUID->equals($dbGUID)) {
    // block request