ImageFetcherService.php

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<?php
 
namespace Elgg\Assets;
 
use Elgg\Cache\SystemCache;
use Elgg\Config;
use Elgg\Exceptions\ExceptionInterface;
use Elgg\Exceptions\InvalidArgumentException;
use GuzzleHttp\Cookie\CookieJar;
use GuzzleHttp\Exception\TransferException;
use GuzzleHttp\RequestOptions;
 
class ImageFetcherService {
 
    protected const CACHE_PREFIX = 'image_fetcher_';
    
    protected $client;
    
    public function __construct(
        protected Config $config,
        protected SystemCache $cache,
        protected \ElggSession $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_key = $this->makeCacheKey($image_url);
        $cache = $this->cache->load($cache_key);
        if (isset($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
            $this->cache->save($cache_key, false);
            return false;
        }
        
        if ($response->getStatusCode() !== ELGG_HTTP_OK) {
            $this->cache->save($cache_key, false);
            return false;
        }
        
        $image_contents = $response->getBody()->getContents();
        if (!$this->validateImageData($image_contents)) {
            $this->cache->save($cache_key, false);
            return false;
        }
        
        $result = [
            'data' => $image_contents,
            'content-type' => $response->getHeaderLine('content-type') ?: 'application/octet-stream',
            'name' => basename($image_url),
        ];
        
        $this->cache->save($cache_key, $result);
        
        return $result;
    }
    
    protected function makeCacheKey(string $image_url): string {
        return self::CACHE_PREFIX . md5($image_url);
    }
    
    protected function validateImageData(string $image_data): bool {
        if (empty($image_data)) {
            return false;
        }
        
        $tmp = new \ElggTempFile();
        try {
            $tmp->open('write');
            $tmp->write($image_data);
            $tmp->close();
        } catch (ExceptionInterface $e) {
            // file error
            return false;
        }
        
        $info = getimagesize($tmp->getFilenameOnFilestore());
        
        return is_array($info);
    }
}