ImageFetcherService.php

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<?php

namespace Elgg\Assets;

use Elgg\Cache\SystemCache;
use Elgg\Config;
use Elgg\Exceptions\InvalidArgumentException;
use GuzzleHttp\Cookie\CookieJar;
use GuzzleHttp\Exception\TransferException;
use GuzzleHttp\RequestOptions;

class ImageFetcherService {

    protected const CACHE_PREFIX = 'image_fetcher_';

    protected $cache;
    
    protected $client;

    protected $config;

    protected $session;
    
    public function __construct(Config $config, SystemCache $cache, \ElggSession $session) {
        $this->config = $config;
        $this->cache = $cache;
        $this->session = $session;
        
        $this->client = elgg_get_http_client();
    }
    
    public function getImage(string $image_url) {
        if (empty($image_url)) {
            throw new InvalidArgumentException('a non-empty image url is required for image fetching');
        }
        
        $image_url = htmlspecialchars_decode($image_url);
        $image_url = elgg_normalize_url($image_url);
        
        $cache = $this->loadFromCache($image_url);
        if (!empty($cache)) {
            return $cache;
        }
        
        $site = elgg_get_site_entity();
        $options = [];
        
        if (stripos($image_url, $site->getURL()) === 0) {
            // internal url, can use session cookie
            $cookie_config = $this->config->getCookieConfig();
            
            $cookies = [
                $cookie_config['session']['name'] => $this->session->getID(),
            ];
            
            $domain = $cookie_config['session']['domain'] ?: $site->getDomain();
            
            $cookiejar = CookieJar::fromArray($cookies, $domain);
            $options[RequestOptions::COOKIES] = $cookiejar;
        }
        
        try {
            $response = $this->client->get($image_url, $options);
        } catch (TransferException $e) {
            // this shouldn't happen, but just in case
            return false;
        }
        
        if ($response->getStatusCode() !== ELGG_HTTP_OK) {
            return false;
        }
        
        $result = [
            'data' => $response->getBody()->getContents(),
            'content-type' => $response->getHeaderLine('content-type') ?: 'application/octet-stream',
            'name' => basename($image_url),
        ];
        
        $this->saveToCache($image_url, $result);
        
        return $result;
    }
    
    protected function loadFromCache(string $image_url): array {
        $cache = $this->cache->load(self::CACHE_PREFIX . md5($image_url));
        
        return is_array($cache) ? $cache : [];
    }
    
    protected function saveToCache(string $image_url, array $data): bool {
        return $this->cache->save(self::CACHE_PREFIX . md5($image_url), $data);
    }
}