From 60ac522435f7efc57cae2fa4d6d0acb871bbdffe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20P=C3=B6ttker?= <bjoern@poettker-holtrup.de>
Date: Mon, 4 May 2026 16:35:20 +0200
Subject: [PATCH] fix: prevent processing of empty files in PDF service and
 scanner watcher

---
 paperless-backend/src/preprocessing/pdf.service.ts  |  6 ++++++
 .../src/scanner/scanner-watcher.service.ts          | 13 ++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/paperless-backend/src/preprocessing/pdf.service.ts b/paperless-backend/src/preprocessing/pdf.service.ts
index 7fe63bd..11633d7 100644
--- a/paperless-backend/src/preprocessing/pdf.service.ts
+++ b/paperless-backend/src/preprocessing/pdf.service.ts
@@ -40,6 +40,12 @@ export class PdfService {
    * Verwendet einen einzigen Ghostscript-Aufruf mit %d-Platzhalter für alle Seiten.
    */
   async pdfToImages(pdfPath: string, dpi = 200): Promise<string[]> {
+    const stat = await fs.stat(pdfPath);
+    if (stat.size === 0) {
+      this.logger.warn(`PDF ist leer (0 Bytes), wird übersprungen: ${pdfPath}`);
+      return [];
+    }
+
     const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'pdf-'));
 
     await execFileAsync('gs', [
diff --git a/paperless-backend/src/scanner/scanner-watcher.service.ts b/paperless-backend/src/scanner/scanner-watcher.service.ts
index 2394114..4f4c7b7 100644
--- a/paperless-backend/src/scanner/scanner-watcher.service.ts
+++ b/paperless-backend/src/scanner/scanner-watcher.service.ts
@@ -143,7 +143,7 @@ export class ScannerWatcherService implements OnModuleInit, OnModuleDestroy {
   private async isStable(filePath: string): Promise<boolean> {
     try {
       const stat = await fs.stat(filePath);
-      return Date.now() - stat.mtimeMs >= STABILITY_MS;
+      return stat.size > 0 && Date.now() - stat.mtimeMs >= STABILITY_MS;
     } catch {
       return false;
     }
@@ -164,6 +164,17 @@ export class ScannerWatcherService implements OnModuleInit, OnModuleDestroy {
     const fileName = parts[1];
 
     if (this.processing.has(filePath)) return;
+
+    try {
+      const stat = await fs.stat(filePath);
+      if (stat.size === 0) {
+        this.logger.debug(`Überspringe leere Datei: ${filePath}`);
+        return;
+      }
+    } catch {
+      return;
+    }
+
     this.processing.add(filePath);
 
     try {