CacheItemInterface::setExpiration improved

README.md

For the moment the $ttl argument is :

• an integer: it is interpreted as the number of seconds after which the item MUST be considered expired.
• a DateTime: it is interpreted as the point in time after which the item MUST be considered expired.

As seen in this implementation example $ttl could be :

• an integer: it is interpreted as the number of seconds after which the item MUST be considered expired.
• a DateInterval: it is interpreted as the interval after which the item MUST be considered expired
• a DateTimeInterface: it is interpreted as the point in time after which the item MUST be considered expired.
• null: a default value MAY be used. If none is set, the value should be stored permanently or for as long as the implementation allows.

PRO:

• It allows the addition of DateTimeImmutable and DateInterval as supported types

CONS:

• Should we use DateTimeInterface (PHP5.5+) only or explicitly state DateTime (PHP5.2+) AND DateTimeImmutable (PHP5.5+) ?
• DateTimeInterval means PHP 5.3+ only compatible PHP.

Adding others types raises the question for a minimal PHP version to be used with this PSR. Obviously using DateTime and namespace means the implicit minimal PHP version is PHP 5.3

TL;DR:

• No change means other added types MUST be documented at the library level: less interoperability
• Change means more flexibility at the interface level: more code for any library that wants to implement the Cache and higher PHP version requirement

CacheItem.php

<?php

namespace CacheLib;

use DateTime;
use DateTimeInterface;
use DateTimeInterval;
use Psr\Cache\CacheItemInterface

class CacheItem implements CacheItemInterface
{
    private $defaultExpirationInterval = 300;
    
    ...
    
    /**
     * Sets the expiration for this cache item.
     *
     * @param int|\DateInterval|\DateTimeInterface $ttl
     *
     * @return static
     *   The called object.
     */
    public function setExpiration($ttl = null)
    {
        if ($ttl instanceof DateTimeInterface) {
            $this->expiration = $ttl;

            return $this;
        } elseif ($ttl instanceof DateTimeInterval) {
            $this->expiration = (new DateTime)->add($ttl);

            return $this;
        }
        $add = filter_var($ttl, FILTER_VALIDATE_INT, ['options' => [
            'min_range' => 0,
            'default' => $this->defaultExpirationInterval
        ]]);
        $this->expiration = new DateTime($add . ' SECONDS');

        return $this;
    }
}