CacheMiddleware.php

<?php
//
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// | CODE INC. SOURCE CODE                                               |
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// | Copyright (c) 2017 - Code Inc. SAS - All Rights Reserved.           |
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// +---------------------------------------------------------------------+
//
// Author:   Joan Fabrégat <joan@codeinc.fr>
// Date:     04/03/2018
// Time:     08:38
// Project:  HttpHeadersMiddleware
//
declare(strict_types = 1);
namespace CodeInc\HttpHeadersMiddleware;
use CodeInc\HttpHeadersMiddleware\Tests\CacheMiddlewareTest;
use CodeInc\Psr7Responses\NotModifiedResponse;
use Micheh\Cache\CacheUtil;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;


/**
 * Class CacheMiddleware
 *
 * @uses CacheUtil
 * @see CacheMiddlewareTest
 * @package CodeInc\HttpHeadersMiddleware
 * @author Joan Fabrégat <joan@codeinc.fr>
 * @license MIT <https://github.com/CodeIncHQ/HttpHeadersMiddleware/blob/master/LICENSE>
 * @link https://github.com/CodeIncHQ/HttpHeadersMiddleware
 */
class CacheMiddleware implements MiddlewareInterface
{
	/**
	 * @var \DateTime|null
	 */
	private $lastModified;

	/**
	 * @var string|null
	 */
	private $etag;

    /**
     * @var bool
     */
	private $public;

    /**
     * @var int
     */
	private $maxAge;


    /**
     * CacheMiddleware constructor.
     *
     * @param bool $public
     * @param int $maxAge
     * @param \DateTime|null $lastModified
     * @param null|string $etag
     */
	public function __construct(bool $public = false, int $maxAge = 600, ?\DateTime $lastModified = null,
        ?string $etag = null)
    {
        $this->public = $public;
        $this->maxAge = $maxAge;
        if ($lastModified) {
            $this->setLastModified($lastModified);
        }
        if ($etag) {
            $this->setEtag($etag);
        }
    }


    /**
     * Defines if the cache is public
     *
     * @param bool $isPublic
     */
	public function setPublic(bool $isPublic):void
    {
        $this->public = $isPublic;
    }


    /**
     * @return bool
     */
    public function isPublic():bool
    {
        return $this->public;
    }


    /**
     * @param int $maxAge
     */
    public function setMaxAge(int $maxAge):void
    {
        $this->maxAge = $maxAge;
    }


    /**
     * @return int
     */
    public function getMaxAge():int
    {
        return $this->maxAge;
    }


	/**
	 * @param \DateTime|null $lastModified
	 */
	public function setLastModified(?\DateTime $lastModified):void
	{
		$this->lastModified = $lastModified;
	}


	/**
	 * @return \DateTime|null
	 */
	public function getLastModified():?\DateTime
	{
		return $this->lastModified;
	}


	/**
	 * @param null|string $etag
	 */
	public function setEtag(?string $etag):void
	{
		$this->etag = $etag;
	}


	/**
	 * @return null|string
	 */
	public function getEtag():?string
	{
		return $this->etag;
	}

	/**
	 * @inheritdoc
	 * @param ServerRequestInterface $request
	 * @param RequestHandlerInterface $handler
	 * @return ResponseInterface
	 */
	public function process(ServerRequestInterface $request,
        RequestHandlerInterface $handler):ResponseInterface
	{
	    // processing
		$response = $handler->handle($request);

		// adding cache headers
		$cacheUtils = new CacheUtil();
		$response = $cacheUtils->withCache($response, $this->public, $this->maxAge);

		// adding eTag
		if ($this->etag) {
			$response = $cacheUtils->withETag($response, $this->etag);
		}

		// adding last modified
		if ($this->lastModified) {
			$response = $cacheUtils->withLastModified($response, $this->lastModified);
			if ($cacheUtils->isNotModified($request, $response)) {
				return new NotModifiedResponse();
			}
		}

		return $response;
	}
}