Clock

In PHP, you can retrieve the current time by creating a DateTime(Immutable) instance. PHP resolves the actual time from a system context. This means that time is a global resource and global resources are hard to control.

In cases where time (or the passing of time) is important, introducing a system clock can be very beneficial. A system clock is used to supply time to you application.

EventSauce ships with two implementations of the EventSauce\EventSourcing\Time\Clock interface. The EventSauce\EventSourcing\Time\SystemClock supplies the current time, and the EventSauce\EventSourcing\Time\TestClock can be fixated and manipulated for testing purposes.

Using the Clock

<?php

use EventSauce\EventSourcing\Time\SystemClock;

// By default the UTC time zone is used, you can specify the one you need.
$clock = new SystemClock(/* optional */ new DateTimeZone('Europe/Amsterdam'));

/** @var DateTimeImmutable $currentTime */
$currentTime = $clock->now();

/** @var DateTimeZone $timeZone */
$timeZone = $clock->timeZone();

Using the TestClock

use EventSauce\EventSourcing\Time\TestClock;

// By default the UTC time zone is used, you can specify the one you need.
$clock = new TestClock(/* optional */ new DateTimeZone('Europe/Amsterdam'));

// Ticking the clock sets the current time to "now".
$clock->tick();

// You can fixate the clock by specifying a point in time (format: Y-m-d H:i:s.u).
$clock->fixate('2020-02-02 02:02:02');

// moving the clock forward using a DateInterval
$clock->moveForward(new DateInterval('PT2H'));