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Pure PHP UUID generator
<?php
// Usage
include 'UUID.php';
// Named-based UUID.
$v3uuid = UUID::v3('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
$v5uuid = UUID::v5('1546058f-5a25-4334-85ae-e68f2a44bbaf', 'SomeRandomString');
// Pseudo-random UUID
$v4uuid = UUID::v4();
?>
<?php
/**
* UUID class
*
* The following class generates VALID RFC 4122 COMPLIANT
* Universally Unique IDentifiers (UUID) version 3, 4 and 5.
*
* UUIDs generated validates using OSSP UUID Tool, and output
* for named-based UUIDs are exactly the same. This is a pure
* PHP implementation.
*
* @author Andrew Moore
* @link http://www.php.net/manual/en/function.uniqid.php#94959
*/
class UUID
{
/**
* Generate v3 UUID
*
* Version 3 UUIDs are named based. They require a namespace (another
* valid UUID) and a value (the name). Given the same namespace and
* name, the output is always the same.
*
* @param uuid $namespace
* @param string $name
*/
public static function v3($namespace, $name)
{
if(!self::is_valid($namespace)) return false;
// Get hexadecimal components of namespace
$nhex = str_replace(array('-','{','}'), '', $namespace);
// Binary Value
$nstr = '';
// Convert Namespace UUID to bits
for($i = 0; $i < strlen($nhex); $i+=2)
{
$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
}
// Calculate hash value
$hash = md5($nstr . $name);
return sprintf('%08s-%04s-%04x-%04x-%12s',
// 32 bits for "time_low"
substr($hash, 0, 8),
// 16 bits for "time_mid"
substr($hash, 8, 4),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 3
(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x3000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1
(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
// 48 bits for "node"
substr($hash, 20, 12)
);
}
/**
*
* Generate v4 UUID
*
* Version 4 UUIDs are pseudo-random.
*/
public static function v4()
{
return sprintf('%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
// 32 bits for "time_low"
mt_rand(0, 0xffff), mt_rand(0, 0xffff),
// 16 bits for "time_mid"
mt_rand(0, 0xffff),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 4
mt_rand(0, 0x0fff) | 0x4000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1
mt_rand(0, 0x3fff) | 0x8000,
// 48 bits for "node"
mt_rand(0, 0xffff), mt_rand(0, 0xffff), mt_rand(0, 0xffff)
);
}
/**
* Generate v5 UUID
*
* Version 5 UUIDs are named based. They require a namespace (another
* valid UUID) and a value (the name). Given the same namespace and
* name, the output is always the same.
*
* @param uuid $namespace
* @param string $name
*/
public static function v5($namespace, $name)
{
if(!self::is_valid($namespace)) return false;
// Get hexadecimal components of namespace
$nhex = str_replace(array('-','{','}'), '', $namespace);
// Binary Value
$nstr = '';
// Convert Namespace UUID to bits
for($i = 0; $i < strlen($nhex); $i+=2)
{
$nstr .= chr(hexdec($nhex[$i].$nhex[$i+1]));
}
// Calculate hash value
$hash = sha1($nstr . $name);
return sprintf('%08s-%04s-%04x-%04x-%12s',
// 32 bits for "time_low"
substr($hash, 0, 8),
// 16 bits for "time_mid"
substr($hash, 8, 4),
// 16 bits for "time_hi_and_version",
// four most significant bits holds version number 5
(hexdec(substr($hash, 12, 4)) & 0x0fff) | 0x5000,
// 16 bits, 8 bits for "clk_seq_hi_res",
// 8 bits for "clk_seq_low",
// two most significant bits holds zero and one for variant DCE1.1
(hexdec(substr($hash, 16, 4)) & 0x3fff) | 0x8000,
// 48 bits for "node"
substr($hash, 20, 12)
);
}
public static function is_valid($uuid) {
return preg_match('/^\{?[0-9a-f]{8}\-?[0-9a-f]{4}\-?[0-9a-f]{4}\-?'.
'[0-9a-f]{4}\-?[0-9a-f]{12}\}?$/i', $uuid) === 1;
}
}
?>
@gravataLonga

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commented Dec 15, 2011

could you write the v1 and v2 ? please.

@gravataLonga

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commented Dec 15, 2011

And other thing i could implement this on codeigniter ? what is the license ?

@dahnielson

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Owner Author

commented Dec 17, 2011

I didn't write the code above. I found it in the online PHP Manual where Andrew Moore, the author of the code, had posted it as a comment. I saved the code as a gist to find it more quikly (these neat things get easily lost among the manuals comments).

There's no way to implement UUID v1 and v2 in pure PHP, to my knowledge, as they are based on MAC addresses and DCE security respectively. Also there's no need. An UUID is an UUID no matter the version. The difference between UUID versions is how they were generated.

You should ask the author of the code, Andrew Moore, about the license (see the link in the code comment).

@gravataLonga

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commented Dec 17, 2011

Sorry, your are rigth about the uuid version.

Thanks.

@yh1224

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commented Sep 20, 2013

Thanks for this tool.
RFC 4122 not 4211

@bugalot

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commented Dec 1, 2014

Any licence for that? It would be very helpful for inclusion in various open source projects.
Thanks for this piece of code!

@danitrimujianto

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commented Mar 17, 2015

how to decrypt v5 ?? please...

@webpatser

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commented Jun 16, 2015

mt_rand() is not that random; maybe this helps
https://github.com/webpatser/laravel-uuid

also works without laravel ;-)

@tom--

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commented Jan 19, 2016

For random UUIDs without using mt_rand(), still simple enough to hack to your needs, I offer this Gist.

@oittaa

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commented Nov 29, 2016

I needed UUIDs recently and found the same comment from PHP documentation and made my implementation based on that. If anybody wants to check out my version, you can find it from https://github.com/oittaa/uuid-php/. It's basically a bit cleaned up version from this one, except it tries to use random_bytes and openssl_random_pseudo_bytes for version 4 UUID instead of mt_rand.

@FlorinAsavoaie

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commented Feb 25, 2017

https://gist.github.com/FlorinAsavoaie/525c98d71d719147aa18c931c8336d94

Please update from here. Way more efficient and better randomness for v4.

@nickl-

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commented Mar 26, 2019

Added time-based v1 uuid generation.

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