<?php
function uuid4()
{
    $data = random_bytes(16);
    $data[6] = chr(ord($data[6]) & 0x0f | 0x40); // set version to 0100
    $data[8] = chr(ord($data[8]) & 0x3f | 0x80); // set bits 6-7 to 10
    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
}

echo uuid4();

<?php

require 'vendor/autoload.php';

use UUID\UUID;

// Generate a version 3 (name-based and hashed with MD5) UUID
// Namespaces: NAMESPACE_DNS, NAMESPACE_URL, NAMESPACE_OID, NAMESPACE_X500
$uuid3 = UUID::uuid3(UUID::NAMESPACE_DNS, 'php.net');
echo $uuid3 . "\n"; // 11a38b9a-b3da-360f-9353-a5a725514269

// Generate a version 4 (random) UUID
$uuid4 = UUID::uuid4();
echo $uuid4 . "\n"; // e.g. 2140a926-4a47-465c-b622-4571ad9bb378

// Generate a version 5 (name-based and hashed with SHA1) UUID
$uuid5 = UUID::uuid5(UUID::NAMESPACE_DNS, 'php.net');
echo $uuid5 . "\n"; // c4a760a8-dbcf-5254-a0d9-6a4474bd1b62

// Generate a version 6 (lexicographically sortable) UUID
$uuid6_first = UUID::uuid6();
echo $uuid6_first . "\n"; // e.g. 1ec9414c-232a-6b00-b3c8-9e6bdeced846
$uuid6_second = UUID::uuid6();
var_dump($uuid6_first < $uuid6_second); // bool(true)

// Generate a version 7 (lexicographically sortable) UUID
$uuid7_first = UUID::uuid7();
echo $uuid7_first . "\n"; // e.g. 017f22e2-79b0-7cc3-98c4-dc0c0c07398f
$uuid7_second = UUID::uuid7();
var_dump($uuid7_first < $uuid7_second); // bool(true)

// Generate a version 8 (lexicographically sortable) UUID
$uuid8_first = UUID::uuid8();
echo $uuid8_first . "\n"; // e.g. 017f22e2-79b0-8cc3-98c4-dc0c0c07398f
$uuid8_second = UUID::uuid8();
var_dump($uuid8_first < $uuid8_second); // bool(true)

<?php

require 'vendor/autoload.php';

use UUID\UUID;

// Test if a given string is a valid UUID
$isvalid = UUID::isValid('11a38b9a-b3da-360f-9353-a5a725514269');
var_dump($isvalid); // bool(true)

// The string standard representation of the UUID.
$tostring = UUID::toString('{C4A760A8-DBCF-5254-A0D9-6A4474BD1B62}');
var_dump($tostring); // string(36) "c4a760a8-dbcf-5254-a0d9-6a4474bd1b62"

// Test if two UUIDs are equal
$equals1 = UUID::equals(
    'c4a760a8-dbcf-5254-a0d9-6a4474bd1b62',
    '2140a926-4a47-465c-b622-4571ad9bb378'
);
var_dump($equals1); // bool(false)

$equals2 = UUID::equals(
    'c4a760a8-dbcf-5254-a0d9-6a4474bd1b62',
    'C4A760A8-DBCF-5254-A0D9-6A4474BD1B62'
);
var_dump($equals2); // bool(true)

$equals3 = UUID::equals(
    'urn:uuid:c4a760a8-dbcf-5254-a0d9-6a4474bd1b62',
    '{C4A760A8-DBCF-5254-A0D9-6A4474BD1B62}'
);
var_dump($equals3); // bool(true)

// UUID comparison. Returns < 0 if uuid1 is less than uuid2;
// > 0 if uuid1 is greater than uuid2, and 0 if they are equal.
$cmp1 = UUID::cmp(
    '11a38b9a-b3da-360f-9353-a5a725514269',
    '2140a926-4a47-465c-b622-4571ad9bb378'
);
var_dump($cmp1 < 0); // bool(true)

$cmp2 = UUID::cmp(
    'c4a760a8-dbcf-5254-a0d9-6a4474bd1b62',
    '2140a926-4a47-465c-b622-4571ad9bb378'
);
var_dump($cmp2 > 0); // bool(true)

$cmp3 = UUID::cmp(
    'urn:uuid:c4a760a8-dbcf-5254-a0d9-6a4474bd1b62',
    '{C4A760A8-DBCF-5254-A0D9-6A4474BD1B62}'
);
var_dump($cmp3 === 0); // bool(true)

// Extract Unix time from versions 6, 7, and 8 as a string.
$uuid6_time = UUID::getTime('1ec9414c-232a-6b00-b3c8-9e6bdeced846');
var_dump($uuid6_time); // string(18) "1645557742.0000000"
$uuid7_time = UUID::getTime('017f22e2-79b0-7cc3-98c4-dc0c0c07398f');
var_dump($uuid7_time); // string(18) "1645557742.0000000"
$uuid8_time = UUID::getTime('017f22e2-79b0-8cc3-98c4-dc0c0c07398f');
var_dump($uuid8_time); // string(18) "1645557742.0007977"

// Extract the UUID version.
$uuid_version = UUID::getVersion('2140a926-4a47-465c-b622-4571ad9bb378');
var_dump($uuid_version); // int(4)