AbstractFileSystemStorageHandler.php

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<?php

declare(strict_types=1);

namespace ILIAS\ResourceStorage\StorageHandler\FileSystemBased;

use ILIAS\Filesystem\Filesystem;
use ILIAS\Filesystem\Stream\FileStream;
use ILIAS\Filesystem\Util\LegacyPathHelper;
use ILIAS\FileUpload\Location;
use ILIAS\ResourceStorage\Flavour\Flavour;
use ILIAS\ResourceStorage\Flavour\StorableFlavourDecorator;
use ILIAS\ResourceStorage\Identification\IdentificationGenerator;
use ILIAS\ResourceStorage\Identification\ResourceIdentification;
use ILIAS\ResourceStorage\Identification\UniqueIDIdentificationGenerator;
use ILIAS\ResourceStorage\Resource\StorableResource;
use ILIAS\ResourceStorage\Revision\CloneRevision;
use ILIAS\ResourceStorage\Revision\FileStreamRevision;
use ILIAS\ResourceStorage\Revision\Revision;
use ILIAS\ResourceStorage\Revision\UploadedFileRevision;
use ILIAS\ResourceStorage\StorageHandler\StorageHandler;
use ILIAS\ResourceStorage\StorageHandler\PathGenerator\PathGenerator;
use ILIAS\ResourceStorage\Revision\StreamReplacementRevision;

abstract class AbstractFileSystemStorageHandler implements StorageHandler
{
    protected const DATA = 'data';
    public const FLAVOUR_PATH_PREFIX = 'fl';
    protected \ILIAS\ResourceStorage\StorageHandler\PathGenerator\PathGenerator $path_generator;
    protected \ILIAS\ResourceStorage\Identification\IdentificationGenerator $id;
    protected bool $links_possible = false;
    protected Filesystem $fs;
    protected int $location = Location::STORAGE;

    public function __construct(
        Filesystem $fs,
        int $location = Location::STORAGE,
        bool $determine_linking_possible = false
    ) {
        $this->fs = $fs;
        $this->location = $location;
        $this->id = new UniqueIDIdentificationGenerator();
        if ($determine_linking_possible) {
            $this->links_possible = $this->determineLinksPossible();
        }
    }

    private function determineLinksPossible(): bool
    {
        $random_filename = "test_" . random_int(10000, 99999);

        $original_filename = $this->getStorageLocationBasePath() . "/" . $random_filename . '_orig';
        $linked_filename = $this->getStorageLocationBasePath() . "/" . $random_filename . '_link';
        $cleaner = function () use ($original_filename, $linked_filename): void {
            try {
                $this->fs->delete($original_filename);
            } catch (\Throwable $exception) {
            }
            try {
                $this->fs->delete($linked_filename);
            } catch (\Throwable $exception) {
            }
        };

        try {
            // remove existing files
            $cleaner();

            // create file
            $this->fs->write($original_filename, 'data');
            $stream = $this->fs->readStream($original_filename);

            // determine absolute pathes
            $original_absolute_path = $stream->getMetadata('uri');
            $linked_absolute_path = dirname($original_absolute_path) . "/" . $random_filename . '_link';

            // try linking and unlinking
            $linking = @link($original_absolute_path, $linked_absolute_path);
            $unlinking = @unlink($original_absolute_path);
            $stream->close();
            if ($linking && $unlinking && $this->fs->has($linked_filename)) {
                $cleaner();

                return true;
            }
            $cleaner();
        } catch (\Throwable $exception) {
            return false;
        }
        return false;
    }

    public function getIdentificationGenerator(): IdentificationGenerator
    {
        return $this->id;
    }

    public function has(ResourceIdentification $identification): bool
    {
        return $this->fs->has($this->getFullContainerPath($identification));
    }

    public function getStream(Revision $revision): FileStream
    {
        return $this->fs->readStream($this->getRevisionPath($revision) . '/' . self::DATA);
    }


    public function storeUpload(UploadedFileRevision $revision): bool
    {
        global $DIC;

        $DIC->upload()->moveOneFileTo(
            $revision->getUpload(),
            $this->getRevisionPath($revision),
            $this->location,
            self::DATA
        );

        return true;
    }

    public function storeStream(FileStreamRevision $revision): bool
    {
        try {
            if ($revision->keepOriginal()) {
                $stream = $revision->getStream();
                $this->fs->writeStream($this->getRevisionPath($revision) . '/' . self::DATA, $stream);
                $stream->close();
            } else {
                $original_path = $revision->getStream()->getMetadata('uri');
                if ($this->links_possible) {
                    $this->fs->createDir($this->getRevisionPath($revision));
                    link($original_path, $this->getAbsoluteRevisionPath($revision) . '/' . self::DATA);
                    unlink($original_path);
                } else {
                    $source_fs = LegacyPathHelper::deriveLocationFrom($original_path);
                    if ($source_fs !== Location::STORAGE) {
                        $stream = $revision->getStream();
                        $this->fs->writeStream($this->getRevisionPath($revision) . '/' . self::DATA, $stream);
                        $stream->close();
                        unlink($original_path);
                    } else {
                        $this->fs->rename(
                            LegacyPathHelper::createRelativePath($original_path),
                            $this->getRevisionPath($revision) . '/' . self::DATA
                        );
                    }
                }
                $revision->getStream()->close();
            }
        } catch (\Throwable $exception) {
            return false;
        }

        return true;
    }

    public function cloneRevision(CloneRevision $revision): bool
    {
        $stream = $this->getStream($revision->getRevisionToClone());
        try {
            $this->fs->writeStream($this->getRevisionPath($revision) . '/' . self::DATA, $stream);
            $stream->close();
        } catch (\Throwable $exception) {
            return false;
        }

        return true;
    }

    public function streamReplacement(StreamReplacementRevision $revision): bool
    {
        $stream = $revision->getReplacementStream();
        try {
            $path = $this->getRevisionPath($revision) . '/' . self::DATA;
            if ($this->fs->has($path)) {
                $this->fs->delete($path);
            }
            $this->fs->writeStream($path, $stream);
            $stream->close();
        } catch (\Throwable $exception) {
            return false;
        }

        return true;
    }

    public function deleteRevision(Revision $revision): void
    {
        try {
            $this->fs->deleteDir($this->getRevisionPath($revision));
        } catch (\Throwable $exception) {
        }
    }

    public function hasFlavour(Revision $revision, Flavour $flavour): bool
    {
        return $this->fs->has($this->getFlavourPath($revision, $flavour));
    }


    public function storeFlavour(Revision $revision, StorableFlavourDecorator $storabel_flavour): bool
    {
        $flavour = $storabel_flavour->getFlavour();
        $path = $this->getFlavourPath($revision, $flavour);
        if ($this->fs->has($path)) {
            $this->fs->deleteDir($path); // we remove old files of this flavour.
        }

        foreach ($storabel_flavour->getStreams() as $index => $stream) {
            $index_path = $path . '/' . self::DATA . '_' . $index; // flavour streams are just written with an index name
            $this->fs->writeStream($index_path, $stream);
        }

        return true;
    }

    public function deleteFlavour(Revision $revision, Flavour $flavour): bool
    {
        $path = $this->getFlavourPath($revision, $flavour);
        if ($this->fs->has($path)) {
            $this->fs->deleteDir($path);
            return true;
        }
        return false;
    }


    public function getFlavourStreams(Revision $revision, Flavour $flavour): \Generator
    {
        $path = $this->getFlavourPath($revision, $flavour);
        if (!$this->hasFlavour($revision, $flavour)) {
            return;
        }
        foreach ($this->fs->finder()->in([$path])->files()->sortByName()->getIterator() as $item) {
            yield $this->fs->readStream($item->getPath());
        }
    }


    public function deleteResource(StorableResource $resource): void
    {
        try {
            $this->fs->deleteDir($this->getFullContainerPath($resource->getIdentification()));
        } catch (\Throwable $exception) {
        }
        try {
            $this->cleanUpContainer($resource);
        } catch (\Throwable $exception) {
        }
    }

    public function cleanUpContainer(StorableResource $resource): void
    {
        $storage_path = $this->getStorageLocationBasePath();
        $container_path = $this->getContainerPathWithoutBase($resource->getIdentification());
        $first_level = strtok($container_path, "/");
        if (!empty($first_level)) {
            $full_first_level = $storage_path . '/' . $first_level;
            $number_of_files = $this->fs->finder()->files()->in([$full_first_level])->count();
            if ($number_of_files === 0) {
                $this->fs->deleteDir($full_first_level);
            }
        }
    }

    public function getBasePath(ResourceIdentification $identification): string
    {
        return $this->getFullContainerPath($identification);
    }

    public function getFlavourPath(Revision $revision, Flavour $flavour): string
    {
        return $this->getRevisionPath($revision)
            . '/' . self::FLAVOUR_PATH_PREFIX
            . '/' . $flavour->getPersistingName();
    }

    public function clearFlavours(Revision $revision): void
    {
        $this->fs->deleteDir($this->getRevisionPath($revision) . '/' . self::FLAVOUR_PATH_PREFIX);
    }

    public function getRevisionPath(Revision $revision): string
    {
        return $this->getFullContainerPath($revision->getIdentification()) . '/' . $revision->getVersionNumber();
    }

    public function getFullContainerPath(ResourceIdentification $identification): string
    {
        return $this->getStorageLocationBasePath() . '/' . $this->getContainerPathWithoutBase($identification);
    }

    public function getContainerPathWithoutBase(ResourceIdentification $identification): string
    {
        return $this->path_generator->getPathFor($identification);
    }

    private function getAbsoluteRevisionPath(Revision $revision): string
    {
        return rtrim(CLIENT_DATA_DIR, "/") . "/" . ltrim($this->getRevisionPath($revision), "/");
    }

    public function movementImplementation(): string
    {
        return $this->links_possible ? 'link' : 'rename';
    }

    public function getPathGenerator(): PathGenerator
    {
        return $this->path_generator;
    }
}