Generate a UUID in PHP

How to Generate a UUID in PHP

PHP does not have built-in support for generating RFC 4122 compliant UUIDs. The function, uniqid(), is not a sufficient replacement for generating RFC 4122 compliant UUIDs as it may not always generate a unique value (especially if your computer is fast) and it can only generate a maximum of 23 characters.

However, below you'll find two, viable 3rd-party solutions for generating RFC 4122 compliant UUIDs in PHP.

1. Roll-Your-Own UUID Generation Function in PHP

This small helper function generates RFC 4122 compliant Version 4 UUIDs.

function guidv4($data = null) {
    // Generate 16 bytes (128 bits) of random data or use the data passed into the function.
    $data = $data ?? random_bytes(16);
    assert(strlen($data) == 16);

    // Set version to 0100
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40);
    // Set bits 6-7 to 10
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80);

    // Output the 36 character UUID.
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
}

Notes

• This function requires PHP 7 or later because of the use of the function random_bytes on line #3.
• If you're using PHP 5 or earlier and have the openssl extension installed, you could use openssl_random_pseudo_bytes(16), instead of random_bytes(16) on line #3.
• Credits go to this answer on Stackoverflow for this solution.
• An example usage of this function would look like this:

  $myuuid = guidv4();
  echo $myuuid;
  

2. Use the ramsey/uuid PHP Library

If you're using Composer for managing dependencies in your PHP project, you can use the ramsey/uuid PHP library for generating UUIDs.

To get started with the library, you can install and add it to your project like this:

% composer require ramsey/uuid

Now you can use it in your PHP project. Here is a small example of generating a UUID with this library:

use Ramsey/Uuid/Uuid;

$myuuid = Uuid::uuid4();
printf("Your UUID is: %s", $myuuid->toString());

How can we improve this page? Let us know!