Added command to delete previews generated by the app

appinfo/info.xml

@@ -20,4 +20,7 @@
         <nextcloud min-version="17" max-version="23"/>
     </dependencies>
     <types><filesystem/></types>
+    <commands>
+        <command>OCA\CameraRawPreviews\Command\DeletePreviews</command>
+    </commands>
 </info>

lib/Command/DeletePreviews.php

@@ -0,0 +1,257 @@
+<?php
+
+namespace OCA\CameraRawPreviews\Command;
+
+use Exception;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\Encryption\IManager;
+use OCP\Files\NotFoundException;
+use OCP\IConfig;
+use OCP\IDBConnection;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+
+class DeletePreviews extends Command
+{
+    /** @var string */
+    protected $appName;
+
+    /** @var IConfig */
+    protected $config;
+
+    /** @var IDBConnection */
+    protected $connection;
+
+    /** @var OutputInterface */
+    protected $output;
+
+    /** @var IManager */
+    protected $encryptionManager;
+
+    /** @var string */
+    protected $instanceId;
+
+    /** @var string */
+    protected $dataDirectory;
+
+    /**
+     * @param string $appName
+     * @param IConfig $config
+     * @param IDBConnection $connection
+     * @param IManager $encryptionManager
+     */
+    public function __construct(
+        $appName,
+        IConfig $config,
+        IDBConnection $connection,
+        IManager $encryptionManager
+    )
+    {
+        parent::__construct();
+
+        $this->appName = $appName;
+        $this->config = $config;
+        $this->connection = $connection;
+        $this->encryptionManager = $encryptionManager;
+        $this->instanceId = $this->config->getSystemValue('instanceid');
+        $this->dataDirectory = $this->config->getSystemValue('datadirectory');
+    }
+
+    protected function configure()
+    {
+        $this
+            ->setName('camerarawpreviews:delete-previews')
+            ->setDescription('Delete generated previews by the CameraRawPreviews')
+            ->addOption(
+                'mime',
+                'm',
+                InputOption::VALUE_OPTIONAL | InputOption::VALUE_IS_ARRAY,
+                'Specify mime types to delete. Default --mime=image/x-dcraw --mime=image/x-indesign'
+            )
+            ->addOption(
+                'force',
+                'f',
+                InputOption::VALUE_NONE,
+                'Needed to delete files'
+            );
+    }
+
+    /**
+     * @param InputInterface $input
+     * @param OutputInterface $output
+     * @return int
+     * @throws Exception
+     */
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        if ($this->encryptionManager->isEnabled()) {
+            $output->writeln('<error>This command does work with encryption.</error>');
+            return 1;
+        }
+
+        $mimes = $input->getOption('mime');
+        if (empty($mimes)) {
+            $mimes = ['image/x-dcraw', 'image/x-indesign'];
+        }
+
+        $dryRun = !$input->getOption('force');
+        $this->output = $output;
+        $count = $this->work($dryRun, $mimes);
+
+        if ($count > 1) {
+            $output->writeln("<info>Deleted previews for $count file(s).</info>");
+        } else if ($count === 1) {
+            $output->writeln("<info>Deleted previews for $count file(s).</info>");
+        } else {
+            $output->writeln("<info>Nothing to delete.</info>");
+        }
+
+        return 0;
+    }
+
+    private function work(bool $dryRun, array $mimes)
+    {
+        $appdataFolder = 'appdata_' . $this->instanceId;
+        $previewFolder = $appdataFolder . '/preview';
+        $lastFolderId = null;
+        $deleteCount = 0;
+        $previewCount = null;
+
+        while (true) {
+
+            $qb = $this->connection->getQueryBuilder();
+            $qb
+                ->select('c2.fileid', 'c2.storage', 'c2.path')
+                ->from('filecache', 'c1')
+                ->from('filecache', 'c2')
+                ->from('mimetypes', 'm')
+                ->where($qb->expr()->in('m.mimetype', $qb->createNamedParameter($mimes, $qb::PARAM_STR_ARRAY)))
+                ->andWhere($qb->expr()->eq('m.id', 'c1.mimetype'))
+                ->andWhere($qb->expr()->eq('c2.name', 'c1.fileid'))
+                ->andWhere($qb->expr()->like('c2.path', $qb->createNamedParameter($previewFolder . '/%', $qb::PARAM_STR)))
+                ->setFirstResult($deleteCount)
+                ->setMaxResults(100);
+
+
+            $stmt = $qb->executeQuery();
+            $previewFolders = $stmt->fetchAll();
+            $stmt->closeCursor();
+
+            if (count($previewFolders) === 0) {
+                break;
+            }
+
+            foreach ($previewFolders as &$folder) {
+                if ($lastFolderId === $folder['fileid']) {
+                    return;
+                }
+                $lastFolderId = $folder['fileid'];
+
+                $re = '/^appdata_\w+\/preview\/.+\/(\d+)$/';
+
+                if (!preg_match($re, $folder['path'], $matches)) {
+                    throw new Exception('Could not extract out file id for preview: ' . json_encode($folder));
+                }
+                $originalImageFileId = $matches[1];
+                $qb = $this->connection->getQueryBuilder();
+                $qb->select('path')
+                    ->from('filecache')
+                    ->where(
+                        $qb->expr()->eq('fileid', $qb->createNamedParameter($originalImageFileId))
+                    );
+                $cursor = $qb->executeQuery();
+                $originalImageFile = $cursor->fetch();
+                $cursor->closeCursor();
+
+                if ($originalImageFile === false) {
+                    continue;
+                }
+
+                $deleteCount++;
+
+                if ($dryRun) {
+                    $this->output->writeln("<info>DRY RUN: Successfully deleted all previews for $originalImageFile[path]</info>");
+                    continue;
+                }
+
+                if ($this->deletePreviews($folder)) {
+                    $this->output->writeln("<info>Successfully deleted all previews for $originalImageFile[path]</info>");
+                }
+            }
+        }
+
+        return $deleteCount;
+    }
+
+    private function deletePreviews($folder): bool
+    {
+        $folderDirectory = "$this->dataDirectory/$folder[path]";
+
+        if (!file_exists($folderDirectory)) {
+            throw new NotFoundException("$folder[path] is not there.");
+        }
+
+        if (!is_writable($folderDirectory)) {
+            $this->output->writeln("<error>folder [$folderDirectory] is not writeable.</error>");
+            return false;
+        }
+
+        $qb = $this->connection->getQueryBuilder();
+        $qb->select('*')
+            ->from('filecache')
+            ->where($qb->expr()->eq('parent', $qb->createNamedParameter($folder['fileid'])))
+            ->andWhere($qb->expr()->like('path', $qb->createNamedParameter("$folder[path]/%")))
+            ->andWhere($qb->expr()->eq('storage', $qb->createNamedParameter($folder['storage'])));
+
+        $cursor = $qb->executeQuery();
+        $previews = $cursor->fetchAll();
+        $cursor->closeCursor();
+        foreach ($previews as $preview) {
+            $previewRealPath = "$this->dataDirectory/$preview[path]";
+
+            if (file_exists($previewRealPath) && !is_writable($previewRealPath)) {
+                $this->output->writeln("<error>$previewRealPath is not writeable.</error>");
+                return false;
+            }
+
+            $this->connection->beginTransaction();
+            try {
+                $qb->delete('filecache')
+                    ->where($qb->expr()->eq('fileid', $qb->createNamedParameter($preview['fileid'])));
+                $qb->executeStatement();
+                if (!file_exists($previewRealPath)) {
+                    throw new NotFoundException("$preview[path] is not there.");
+                }
+                if (!unlink($previewRealPath)) {
+                    throw new Exception("Could not delete $preview[path]");
+                }
+                $this->connection->commit();
+            } catch (Exception $e) {
+                $this->output->writeln('<error>' . $e->getMessage() . '</error>');
+                $this->connection->rollBack();
+                return false;
+            }
+
+        }
+
+        $this->connection->beginTransaction();
+        try {
+            $qb->delete('filecache')
+                ->where($qb->expr()->eq('fileid', $qb->createNamedParameter($folder['fileid'])));
+            $qb->executeStatement();
+            if (!rmdir($folderDirectory)) {
+                throw new Exception("Could not delete $folder[path]");
+            }
+            $this->connection->commit();
+        } catch (Exception $e) {
+            $this->output->writeln('<error>' . $e->getMessage() . '</error>');
+            $this->connection->rollBack();
+            return false;
+        }
+
+        return true;
+    }
+}