# ramsey/uuid

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ramsey/uuid is a PHP library for generating and working with [RFC 4122][rfc4122]
version 1, 2, 3, 4, and 5 universally unique identifiers (UUID).

This project adheres to a [Contributor Code of Conduct][conduct]. By
participating in this project and its community, you are expected to uphold this
code.

From [Wikipedia](http://en.wikipedia.org/wiki/Universally_unique_identifier):

> The intent of UUIDs is to enable distributed systems to uniquely identify
> information without significant central coordination. In this context the word
> unique should be taken to mean "practically unique" rather than "guaranteed
> unique". Since the identifiers have a finite size, it is possible for two
> differing items to share the same identifier. The identifier size and
> generation process need to be selected so as to make this sufficiently
> improbable in practice. Anyone can create a UUID and use it to identify
> something with reasonable confidence that the same identifier will never be
> unintentionally created by anyone to identify something else. Information
> labeled with UUIDs can therefore be later combined into a single database
> without needing to resolve identifier (ID) conflicts.

Much inspiration for this library came from the [Java][javauuid] and
[Python][pyuuid] UUID libraries.


## Installation

The preferred method of installation is via [Composer][]. Run the following
command to install the package and add it as a requirement to your project's
`composer.json`:

```bash
composer require ramsey/uuid
```


## Upgrading from 3.x to 4.x

_This section is a draft. It is incomplete._

In the 4.x series, the following methods will always return strings:

* `UuidInterface::getInteger()`
* `Uuid::getTimeLow()`
* `Uuid::getTimeMid()`
* `Uuid::getTimeHiAndVersion()`
* `Uuid::getClockSequence()`
* `Uuid::getClockSeqHiAndReserved()`
* `Uuid::getClockSeqLow()`
* `Uuid::getNode()`
* `Uuid::getLeastSignificantBits()`
* `Uuid::getMostSignificantBits()`

In 3.x, these methods returned varying types, depending on the environment:
`int`, `string`, or `Moontoast\Math\BigNumber`. Moving to a string return type
provides you with the flexibility to use the arbitrary-precision arithmetic
library of your choice (i.e., bcmath, gmp, moontoast/math, phpseclib/phpseclib,
brick/math, etc.).

While still on the ramsey/uuid 3.x series, you may ease this transition by
casting the return value these methods to a string and passing the result to a
`Moontoast\Math\BigNumber` object (if already using moontoast/math) or
transitioning to brick/math, etc. For example:

``` php
$bigNumber = new \Moontoast\Math\BigNumber($uuid->getInteger()->toString());

// or

$bigInteger = \Brick\Math\BigInteger::of($uuid->getInteger()->toString());
```

In 4.x, `Uuid::getFields()` returns an instance of `Fields\FieldsInterface`.
Previously, it returned an array of integer values (on 64-bit systems only).

For methods of `Fields\FieldsInterface` that return UUID fields (e.g.
`getTimeLow()`, `getNode()`, etc.) use the return type `Type\Hexadecimal`. If
you need the integer values for these fields, we recommend using the
arbitrary-precision library of your choice (i.e., bcmath, gmp, brick/math, etc.)
to convert them. Each is an unsigned integer, and some fields (time low, and
node) are large enough that they will overflow the system's max integer values,
so arbitrary-precision arithmetic is necessary to operate on them.

For example, you may choose brick/math to convert the node field to a string
integer:

``` php
// This works only in ramsey/uuid 4.x.
$bigInteger = \Brick\Math\BigInteger::fromBase($uuid->getFields()->getNode(), 16);
```

While still on the ramsey/uuid 3.x series, you may ease this transition by
building an array like this:

``` php
use Brick\Math\BigInteger;

$fields = [
    'time_low' => (string) BigInteger::fromBase($uuid->getTimeLowHex(), 16),
    'time_mid' => (string) BigInteger::fromBase($uuid->getTimeMidHex(), 16),
    'time_hi_and_version' => (string) BigInteger::fromBase($uuid->getTimeHiAndVersionHex(), 16),
    'clock_seq_hi_and_reserved' => (string) BigInteger::fromBase($uuid->getClockSeqHiAndReservedHex(), 16),
    'clock_seq_low' => (string) BigInteger::fromBase($uuid->getClockSeqLowHex(), 16),
    'node' => (string) BigInteger::fromBase($uuid->getNodeHex(), 16),
];
```


## Upgrading from 2.x to 3.x

While we have made significant internal changes to the library, we have made
every effort to ensure a seamless upgrade path from the 2.x series of this
library to 3.x.

One major breaking change is the transition from the `Rhumsaa` root namespace to
`Ramsey`. In most cases, all you will need is to change the namespace to
`Ramsey` in your code, and everything will "just work."

Here are full details on the breaking changes to the public API of this library:

1. All namespace references of `Rhumsaa` have changed to `Ramsey`. Simply change
   the namespace to `Ramsey` in your code and everything should work.
2. The console application has moved to
   [ramsey/uuid-console](https://packagist.org/packages/ramsey/uuid-console).
   If using the console functionality, use Composer to require
   `ramsey/uuid-console`.
3. The Doctrine field type mapping has moved to
   [ramsey/uuid-doctrine](https://packagist.org/packages/ramsey/uuid-doctrine).
   If using the Doctrine functionality, use Composer to require
   `ramsey/uuid-doctrine`.


## What to do if you see a "rhumsaa/uuid is abandoned" message

When installing your project's dependencies using Composer, you might see the
following message:

```
Package rhumsaa/uuid is abandoned, you should avoid using it. Use
ramsey/uuid instead.
```

Don't panic. Simply execute the following commands with Composer:

``` bash
composer remove rhumsaa/uuid
composer require ramsey/uuid=^2.9
```

After doing so, you will have the latest ramsey/uuid package in the 2.x series,
and there will be no need to modify any code; the namespace in the 2.x series is
still `Rhumsaa`.


## Examples

See the [cookbook on the wiki][wiki-cookbook] for more examples and approaches
to specific use-cases.

```php
<?php
require 'vendor/autoload.php';

use Ramsey\Uuid\Uuid;
use Ramsey\Uuid\Exception\UnsatisfiedDependencyException;

try {

    // Generate a version 1 (time-based) UUID object
    $uuid1 = Uuid::uuid1();
    echo $uuid1->toString() . "\n"; // i.e. e4eaaaf2-d142-11e1-b3e4-080027620cdd

    // Generate a version 3 (name-based and hashed with MD5) UUID object
    $uuid3 = Uuid::uuid3(Uuid::NAMESPACE_DNS, 'php.net');
    echo $uuid3->toString() . "\n"; // i.e. 11a38b9a-b3da-360f-9353-a5a725514269

    // Generate a version 4 (random) UUID object
    $uuid4 = Uuid::uuid4();
    echo $uuid4->toString() . "\n"; // i.e. 25769c6c-d34d-4bfe-ba98-e0ee856f3e7a

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

} catch (UnsatisfiedDependencyException $e) {

    // Some dependency was not met. Either the method cannot be called on a
    // 32-bit system, or it can, but it relies on Moontoast\Math to be present.
    echo 'Caught exception: ' . $e->getMessage() . "\n";

}
```


## Contributing

Contributions are welcome! Please read [CONTRIBUTING.md][] for details.


## Copyright and License

The ramsey/uuid library is copyright © [Ben Ramsey](https://benramsey.com/) and
licensed for use under the MIT License (MIT). Please see [LICENSE][] for more
information.


[rfc4122]: http://tools.ietf.org/html/rfc4122
[conduct]: https://github.com/ramsey/uuid/blob/master/.github/CODE_OF_CONDUCT.md
[javauuid]: http://docs.oracle.com/javase/6/docs/api/java/util/UUID.html
[pyuuid]: http://docs.python.org/3/library/uuid.html
[composer]: http://getcomposer.org/
[moontoast\math]: https://packagist.org/packages/moontoast/math
[ext-gmp]: http://php.net/manual/en/book.gmp.php
[wiki-cookbook]: https://github.com/ramsey/uuid/wiki/Ramsey%5CUuid-Cookbook
[contributing.md]: https://github.com/ramsey/uuid/blob/master/.github/CONTRIBUTING.md

[badge-source]: https://img.shields.io/badge/source-ramsey/uuid-blue.svg?style=flat-square
[badge-release]: https://img.shields.io/packagist/v/ramsey/uuid.svg?style=flat-square&label=release
[badge-license]: https://img.shields.io/packagist/l/ramsey/uuid.svg?style=flat-square
[badge-php]: https://img.shields.io/packagist/php-v/ramsey/uuid.svg?style=flat-square
[badge-build]: https://img.shields.io/travis/ramsey/uuid/master.svg?style=flat-square
[badge-coverage]: https://img.shields.io/coveralls/github/ramsey/uuid/master.svg?style=flat-square
[badge-downloads]: https://img.shields.io/packagist/dt/ramsey/uuid.svg?style=flat-square&colorB=mediumvioletred

[source]: https://github.com/ramsey/uuid
[release]: https://packagist.org/packages/ramsey/uuid
[license]: https://github.com/ramsey/uuid/blob/master/LICENSE
[php]: https://php.net
[build]: https://travis-ci.org/ramsey/uuid
[coverage]: https://coveralls.io/github/ramsey/uuid?branch=master
[downloads]: https://packagist.org/packages/ramsey/uuid