Generates, compresses, and expands Univerally Unique Identifers.

This class can generate UUIDs of versions 1 through 7.

It is also possible to create a new instance of this class from a UUID string of any version via the Uuid::createFromString() method.

This class implements the \Stringable interface, so getting the canonical string representation of a UUID is as simple as casting an instance of this class to string.

Because the canonical string representation of a UUID requires 36 characters, e.g. 4e917aef-2843-5b3c-8bf5-a858ee6f36bc, which can be quite cumbersome, this class can also compress and expand UUIDs to and from more compact representations for storage and other uses. In particular:

• The Uuid::getBinary() method returns the 128-bit (16 byte) raw binary representation of a UUID. This form maintains the same sort order as the full form and is the most space-efficient form possible.

• The Uuid::getShortForm() method returns a customized base 64 encoding of the binary form of the UUID. This form is 22 bytes long, maintains the same sort order as the full form, and is URL safe.

For convenience, two static methods, Uuid::compress() and Uuid::expand(), are available in order to simplify the process of converting an existing UUID string between the full, short, or binary forms.

For the purposes of software applications that use relational databases, the most useful UUID versions are v7 and v5:

• UUIDv7 is ideal for generating permanently stored database keys, because these UUIDs naturally sort according to their chronological order of creation. This is the default version when generating a new UUID.

• UUIDv5 is ideal for situations where UUIDs need to be generated on demand from pre-existing data, but will not be stored permanently. The generation algorithm for UUIDv5 always produces the same output given the same input, so these UUIDs can be regenerated any number of times without varying.