Part-DB.Part-DB-server/src/Services/Attachments/AttachmentURLGenerator.php

<?php
/**
 * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
 *
 * Copyright (C) 2019 - 2020 Jan Böhmer (https://github.com/jbtronics)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

declare(strict_types=1);

/**
 * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
 *
 * Copyright (C) 2019 Jan Böhmer (https://github.com/jbtronics)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

namespace App\Services\Attachments;

use App\Entity\Attachments\Attachment;
use InvalidArgumentException;
use Liip\ImagineBundle\Service\FilterService;
use RuntimeException;
use function strlen;
use Symfony\Component\Asset\Packages;
use Symfony\Component\Routing\Generator\UrlGeneratorInterface;

class AttachmentURLGenerator
{
    protected $assets;
    protected $public_path;
    protected $pathResolver;
    protected $urlGenerator;
    protected $attachmentHelper;
    protected $filterService;

    public function __construct(Packages $assets, AttachmentPathResolver $pathResolver,
                                UrlGeneratorInterface $urlGenerator, AttachmentManager $attachmentHelper,
                                FilterService $filterService)
    {
        $this->assets = $assets;
        $this->pathResolver = $pathResolver;
        $this->urlGenerator = $urlGenerator;
        $this->attachmentHelper = $attachmentHelper;
        $this->filterService = $filterService;

        //Determine a normalized path to the public folder (assets are relative to this folder)
        $this->public_path = $this->pathResolver->parameterToAbsolutePath('public');
    }

    /**
     * Converts the absolute file path to a version relative to the public folder, that can be passed to asset
     * Asset Component functions.
     *
     * @param string      $absolute_path the absolute path that should be converted
     * @param string|null $public_path   The public path to which the relative pathes should be created.
     *                                   The path must NOT have a trailing slash!
     *                                   If this is set to null, the global public/ folder is used.
     *
     * @return string|null The relative version of the string. Null if the absolute path was not a child folder
     *                     of public path
     */
    public function absolutePathToAssetPath(string $absolute_path, ?string $public_path = null): ?string
    {
        if (null === $public_path) {
            $public_path = $this->public_path;
        }

        //Our absolute path must begin with public path or we can not use it for asset pathes.
        if (0 !== strpos($absolute_path, $public_path)) {
            return null;
        }

        //Return the part relative after public path.
        return substr($absolute_path, strlen($public_path) + 1);
    }

    /**
     * Returns a URL under which the attachment file can be viewed.
     */
    public function getViewURL(Attachment $attachment): string
    {
        $absolute_path = $this->attachmentHelper->toAbsoluteFilePath($attachment);
        if (null === $absolute_path) {
            throw new RuntimeException('The given attachment is external or has no valid file, so no URL can get generated for it!
                Use Attachment::getURL() to get the external URL!');
        }

        $asset_path = $this->absolutePathToAssetPath($absolute_path);
        //If path is not relative to public path or marked as secure, serve it via controller
        if (null === $asset_path || $attachment->isSecure()) {
            return $this->urlGenerator->generate('attachment_view', ['id' => $attachment->getID()]);
        }

        //Otherwise we can serve the relative path via Asset component
        return $this->assets->getUrl($asset_path);
    }

    /**
     * Returns a URL to an thumbnail of the attachment file.
     */
    public function getThumbnailURL(Attachment $attachment, string $filter_name = 'thumbnail_sm'): string
    {
        if (! $attachment->isPicture()) {
            throw new InvalidArgumentException('Thumbnail creation only works for picture attachments!');
        }

        if ($attachment->isExternal() && ! empty($attachment->getURL())) {
            return $attachment->getURL();
        }

        $absolute_path = $this->attachmentHelper->toAbsoluteFilePath($attachment);
        if (null === $absolute_path) {
            throw new RuntimeException('The given attachment is external or has no valid file, so no URL can get generated for it!');
        }

        $asset_path = $this->absolutePathToAssetPath($absolute_path);
        //If path is not relative to public path or marked as secure, serve it via controller
        if (null === $asset_path || $attachment->isSecure()) {
            return $this->urlGenerator->generate('attachment_view', ['id' => $attachment->getID()]);
        }

        //For builtin ressources it is not useful to create a thumbnail
        //because the footprints images are small and highly optimized already.
        if ('thumbnail_md' === $filter_name && $attachment->isBuiltIn()) {
            return $this->assets->getUrl($asset_path);
        }

        //Otherwise we can serve the relative path via Asset component
        return $this->filterService->getUrlOfFilteredImage($asset_path, $filter_name);
    }

    /**
     * Returns a download link to the file associated with the attachment.
     */
    public function getDownloadURL(Attachment $attachment): string
    {
        //Redirect always to download controller, which sets the correct headers for downloading:
        return $this->urlGenerator->generate('attachment_download', ['id' => $attachment->getID()]);
    }
}