nabble/ajde

<?php

class Ajde_Cache extends Ajde_Object_Singleton
{
    protected $_hashContext;
    protected $_hashFinal;
    protected $_lastModified = [];
    protected $_contents;

    protected $_enabled = true;

    /**
     * @staticvar Ajde_Cache $instance
     *
     * @return Ajde_Cache
     */
    public static function getInstance()
    {
        static $instance;

        return $instance === null ? $instance = new self() : $instance;
    }

    protected function __construct()
    {
        $this->_enabled = config('layout.cache.enabled');
    }

    public function isEnabled()
    {
        return $this->_enabled;
    }

    public function enable()
    {
        $this->_enabled = true;
    }

    public function disable()
    {
        $this->_enabled = false;
    }

    public function getHashContext()
    {
        if (!isset($this->_hashContext)) {
            $this->_hashContext = hash_init('md5');
        }

        return $this->_hashContext;
    }

    public function updateHash($data)
    {
        if (!isset($this->_hashFinal)) {
            hash_update($this->getHashContext(), $data);
        }
    }

    public function addFile($filename)
    {
        if (!isset($this->_hashFinal)) {
            if (is_file(LOCAL_ROOT.$filename)) {
                hash_update_file($this->getHashContext(), LOCAL_ROOT.$filename);
                $this->addLastModified(filemtime(LOCAL_ROOT.$filename));
            }
        }
    }

    public function getHash()
    {
        if (!isset($this->_hashFinal)) {
            $this->_hashFinal = hash_final($this->getHashContext());
        }

        return $this->_hashFinal;
    }

    public function addLastModified($timestamp)
    {
        $this->_lastModified[] = $timestamp;
    }

    public function getLastModified()
    {
        if (empty($this->_lastModified)) {
            return time();
        }

        return max($this->_lastModified);
    }

    public function ETagMatch($serverETag = null)
    {
        if (empty($serverETag) && isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
            $serverETag = $_SERVER['HTTP_IF_NONE_MATCH'];
        }

        return $serverETag == $this->getHash();
    }

    public function modifiedSince()
    {
        if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
            return $this->getLastModified() > strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']);
        }

        return false;
    }

    public function setContents($contents)
    {
        $this->set('contents', $contents);
    }

    public function getContents()
    {
        return $this->get('contents');
    }

    public function saveResponse()
    {
        $response = Ajde::app()->getResponse();
        $document = Ajde::app()->getDocument();

        // Expires and Cache-Control
        if ($document->getCacheControl() == Ajde_Document::CACHE_CONTROL_NOCACHE || $this->isEnabled() == false) {
            $response->addHeader('Expires', gmdate('D, d M Y H:i:s \G\M\T', time()));
            $response->addHeader('Cache-Control', Ajde_Document::CACHE_CONTROL_NOCACHE.', max-age=0');
        } else {
            $response->addHeader('Expires', gmdate('D, d M Y H:i:s \G\M\T', time() + $document->getMaxAge()));
            $response->addHeader('Cache-Control', $document->getCacheControl().', max-age='.$document->getMaxAge());
        }

        // Content
        if (($this->ETagMatch() && !$this->modifiedSince()) && $this->isEnabled()) {
            $response->setResponseType(Ajde_Http_Response::RESPONSE_TYPE_NOT_MODIFIED);
            $response->setData(false);
        } else {
            $response->addHeader('Last-Modified', gmdate('D, d M Y H:i:s', $this->getLastModified()).' GMT');
            $response->addHeader('Etag', $this->getHash());
            $response->addHeader('Content-Type', $document->getContentType());
            $response->setData($this->hasContents() ? $this->getContents() : false);
        }
    }

    /**
     * Remember a cached value in the cache directory as a file.
     *
     * @param string   $key
     * @param callable $callback
     * @param int      $ttl      in seconds, defaults to 3600 (one hour)
     *
     * @return mixed
     */
    public static function remember($key, Closure $callback, $ttl = 3600)
    {
        $safeKey = substr(preg_replace('/[^a-zA-Z0-9_-]/', '-', $key), 0, 100);
        $cacheFilename = CACHE_DIR.'STATIC_CACHE_'.$safeKey;

        if (file_exists(LOCAL_ROOT.$cacheFilename) && filemtime(LOCAL_ROOT.$cacheFilename) > (time() - $ttl)) {
            return json_decode(file_get_contents(LOCAL_ROOT.$cacheFilename));
        } else {
            $result = $callback->__invoke();
            file_put_contents(LOCAL_ROOT.$cacheFilename, json_encode($result));

            return $result;
        }
    }
}