core\uuid Class Reference

V4 UUID generator class. More...

Static Public Member Functions
static	generate ()
	Generate a V4 UUID. More...

Static Protected Member Functions
static	generate_uuid_via_pecl_uuid_extension ()
	Generate a V4 UUID using PECL UUID extension. More...
static	generate_uuid_via_random_bytes ()
	Generate a V4 UUID using PHP 7+ features. More...

Detailed Description

V4 UUID generator class.

Copyright

2019 Matteo Scaramuccia moodl.nosp@m.e@ma.nosp@m.tteos.nosp@m.cara.nosp@m.mucci.nosp@m.a.co.nosp@m.m

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Member Function Documentation

generate()

static core\uuid::generate ( )

static

Generate a V4 UUID.

Unique is hard. Very hard. Attempt to use the PECL UUID function if available, and if not then revert to constructing the uuid using random_bytes or mt_rand.

It is important that this token is not solely based on time as this could lead to duplicates in a clustered environment (especially on VMs due to poor time precision).

UUIDs are just 128 bits long but with different supported versions (RFC 4122), mainly two:

• V1: the goal is uniqueness, at the cost of anonymity since it is coupled to the host generating it, via its MAC address.
• V4: the goal is randomness, at the cost of (rare) collisions. Here, the V4 type is the preferred choice.

The format is: xxxxxxxx-xxxx-4xxx-Yxxx-xxxxxxxxxxxx where x is any hexadecimal digit and Y is a random choice from 8, 9, a, or b.

See also

https://tools.ietf.org/html/rfc4122

Return values

string

The V4 UUID.

generate_uuid_via_pecl_uuid_extension()

static core\uuid::generate_uuid_via_pecl_uuid_extension ( )

staticprotected

Generate a V4 UUID using PECL UUID extension.

See also

https://github.com/php/pecl-networking-uuid PECL uuid

https://tools.ietf.org/html/rfc4122

Return values

string|bool

The UUID when PECL UUID extension is available; otherwise, false.

generate_uuid_via_random_bytes()

static core\uuid::generate_uuid_via_random_bytes ( )

staticprotected

Generate a V4 UUID using PHP 7+ features.

See also

https://www.php.net/manual/en/function.random-bytes.php

https://tools.ietf.org/html/rfc4122

Return values

string|bool

The UUID when random_bytes() function is available; otherwise, false when missing the sources of randomness used by random_bytes().

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The documentation for this class was generated from the following file:

• lib/classes/uuid.php