Time Service Added and REQUEST_TIME deprecated

A new service has been added to Drupal 8.3.x to retrieve the request time or current time. The REQUEST_TIME global constant has also been deprecated, scheduled to be removed before 10.0.0

There are four methods on the service.

Usage

$request_time = $_SERVER['REQUEST_TIME'];
$request_time = REQUEST_TIME;
$request_time = $requestStack->getCurrentRequest()->server->get('REQUEST_TIME');
$request_time = $request->server->get('REQUEST_TIME');

and most instances of

$time = time();

can be replaced with

$request_time = \Drupal::time()->getRequestTime();

or the equivalent using the injected service, 'datetime.time'.

$request_time_float = $_SERVER['REQUEST_TIME_FLOAT'];
$request_time_float = $requestStack->getCurrentRequest()->server->get('REQUEST_TIME_FLOAT');
$request_time_float = $request->server->get('REQUEST_TIME_FLOAT');

and many instances of

$microtime = microtime();
$microtime = microtime(TRUE);

can be replaced with

$request_time = \Drupal::time()->getRequestMicroTime();

or the equivalent using the injected service.

$time = time();

can be replaced with

$request_time = \Drupal::time()->getCurrentTime();

$microtime = microtime();
$microtime = microtime(TRUE);

can be replaced with

$request_time = \Drupal::time()->getCurrentMicroTime();

or the equivalent using the injected service.

Notes

There are instances when the Drupal kernel has not initialized the request stack, and the request time is still needed. As of https://www.drupal.org/project/drupal/issues/3113476, Time::getRequestTime and Time::getRequestMicrotimeTime will both attempt to pick sane alternatives.

In this case, Time::getRequestTime will first see $_SERVER['REQUEST_TIME'] is available, otherwise it will use Time::getCurrentTime. Time::getRequestMicrotimeTime works in a similar manner for the floating point needs.