fix: apply PDF flip transforms on export

Readme.md

@@ -18,7 +18,7 @@ This project is a comprehensive full‑stack web app for doing simple, local fil
 - Reorder PDF pages (files over 50 pages are rejected to avoid truncated exports)
 - Convert PDF to DOCX
 - Convert DOCX to PDF
-- Rotate or flip PDF pages while preserving all source pages
+- Rotate or flip PDF pages (including mirrored export for horizontal/vertical flips) while preserving all source pages
 - Add watermarks to PDFs
 - Sign PDFs
 

backend/blueprints/dpi_converter.py

@@ -1,5 +1,5 @@
 import os
-from flask import Blueprint, request, jsonify
+from flask import Blueprint, request
 from PIL import Image, ImageFile
 from werkzeug.utils import secure_filename
 from utils.helpers import error, send_file_and_cleanup, success

backend/blueprints/image.py

@@ -250,6 +250,13 @@ def compress_image():
         if upload_error:
             return upload_error
 
+        requested_format = request.form.get("format", "original").lower()
+        if requested_format != "original" and requested_format not in COMPRESSION_FORMATS:
+            return error(
+                "Invalid format. Please choose one of: original, jpeg, webp, png.",
+                400,
+            )
+
         img, file_bytes, image_error = validate_image_file(file)
 
         if image_error:
@@ -259,8 +266,6 @@ def compress_image():
 
         quality = max(1, min(100, quality))
 
-        requested_format = request.form.get("format", "original").lower()
-
         if requested_format == "original":
             # Keep the uploaded format, falling back to JPEG for anything the
             # compressor cannot re-encode.
@@ -269,13 +274,8 @@ def compress_image():
                 if img.format in COMPRESSION_EXTENSIONS
                 else "JPEG"
             )
-        elif requested_format in COMPRESSION_FORMATS:
-            img_format = COMPRESSION_FORMATS[requested_format]
         else:
-            return error(
-                "Invalid format. Please choose one of: original, jpeg, webp, png.",
-                400,
-            )
+            img_format = COMPRESSION_FORMATS[requested_format]
 
         # JPEG has no alpha channel, so transparency is flattened onto white
         # instead of turning black. WebP only accepts RGB/RGBA input.
@@ -393,4 +393,4 @@ def resize_image(img, filename, file_bytes):
             try:
                 resized_img.close()
             except Exception:
-                pass
+                pass

backend/blueprints/pdf.py

@@ -36,8 +36,6 @@ def convert_pdf_to_png():
         # Read PDF into memory and open from bytes
         pdf_bytes = pdf_file.read()
 
-        target_lang = request.form.get("language", "eng")
-
         # Extract DPI/resolution settings. Default to 72 DPI (standard screen resolution).
         # DPI determines the scaling: zoom = requested_dpi / 72
         # For 150 DPI: zoom = 150/72 = 2.08

backend/blueprints/pdf_to_docx.py

@@ -6,6 +6,7 @@
 from flask import Blueprint, request
 
 from utils.helpers import error, send_file_and_cleanup
+from utils.validators import validate_pdf_file, validate_uploaded_file
 
 pdf_docx_bp = Blueprint("pdf_docx", __name__)
 
@@ -14,14 +15,15 @@
 def convert_pdf_to_docx():
     doc = None
     try:
-        if "file" not in request.files:
-            return error("No file provided")
+        pdf_file, filename, upload_error = validate_uploaded_file(request, "file")
+        if upload_error:
+            return upload_error
 
-        pdf_file = request.files["file"]
-
-        if pdf_file.filename == "":
-            return error("No file selected")
+        pdf_error = validate_pdf_file(pdf_file, filename)
+        if pdf_error:
+            return pdf_error
 
+        pdf_bytes = pdf_file.read()
         try:
             doc = fitz.open(stream=pdf_bytes, filetype="pdf")
         except Exception:
@@ -64,4 +66,4 @@ def convert_pdf_to_docx():
             "Failed to convert the PDF to DOCX. The file may be corrupted "
             "or unsupported.",
             500,
-        )
+        )

backend/blueprints/removebg.py

@@ -2,7 +2,7 @@
 import threading
 
 import numpy as np
-from flask import Blueprint, jsonify, request, Response
+from flask import Blueprint, jsonify, Response
 from PIL import Image, ImageFilter
 from rembg import remove
 from skimage import morphology

backend/blueprints/watermark.py

@@ -2,7 +2,6 @@
 from PIL import Image, ImageDraw, ImageFont
 from utils.helpers import error
 import io
-import os
 
 watermark_bp = Blueprint('watermark', __name__)
 
@@ -96,7 +95,7 @@ def create_text_watermark(text, font_size, color, opacity):
 
     try:
         color_rgb = tuple(int(color.lstrip('#')[i:i+2], 16) for i in (0, 2, 4))
-    except:
+    except (TypeError, ValueError):
         color_rgb = (255, 255, 255)
 
     alpha = int(255 * opacity / 100)

backend/pyproject.toml

@@ -0,0 +1,5 @@
+[tool.ruff.lint]
+# Keep CI on Ruff's established correctness-focused default rules. Ruff is
+# installed unpinned by the workflow, so pinning the selection prevents future
+# releases from unexpectedly enabling repository-wide style rule families.
+select = ["E4", "E7", "E9", "F"]

backend/test_app.py

@@ -1,4 +1,3 @@
-import os
 import io
 import pytest
 from flask import Flask

backend/tests/test_path_traversal.py

@@ -14,7 +14,6 @@ def test_path_traversal_filename(client):
 
     assert "../" not in header
     assert "..\\" not in header
-import io
 
 def test_nested_path_traversal(client):
     response = client.post(
@@ -28,7 +27,6 @@ def test_nested_path_traversal(client):
     header = response.headers.get("Content-Disposition", "")
 
     assert "../" not in header
-import io
 
 def test_windows_path_traversal(client):
     response = client.post(

backend/tests/test_send_file_helper.py

@@ -10,7 +10,6 @@ def test_normal_filename(app):
         )
 
         assert "hello.txt" in response.headers["Content-Disposition"]
-import io
 
 def test_path_traversal_removed(app):
     with app.test_request_context():
@@ -23,7 +22,6 @@ def test_path_traversal_removed(app):
         header = response.headers["Content-Disposition"]
 
         assert "../" not in header
-import io
 
 def test_windows_traversal_removed(app):
     with app.test_request_context():
@@ -37,7 +35,6 @@ def test_windows_traversal_removed(app):
 
         assert "..\\" not in header
 
-import io
 
 def test_absolute_path_removed(app):
     with app.test_request_context():

backend/tests/test_upload_security_headers.py

@@ -14,7 +14,6 @@ def test_removebg_path_traversal_filename(client):
 
     assert "../" not in header
     assert "..\\" not in header
-import io
 
 def test_removebg_nested_path(client):
     response = client.post(
@@ -31,7 +30,6 @@ def test_removebg_nested_path(client):
     header = response.headers.get("Content-Disposition", "")
 
     assert "../" not in header
-import io
 
 def test_removebg_windows_path(client):
     response = client.post(
@@ -48,7 +46,6 @@ def test_removebg_windows_path(client):
     header = response.headers.get("Content-Disposition", "")
 
     assert "..\\" not in header
-import io
 
 def test_removebg_absolute_path(client):
     response = client.post(

frontend/src/pages/PdfRotateFlip.tsx

@@ -1,9 +1,9 @@
 import { useState, useRef, useEffect } from "react";
 import * as pdfjsLib from "pdfjs-dist/legacy/build/pdf";
 import pdfWorker from "pdfjs-dist/legacy/build/pdf.worker.min.mjs?url";
-import { PDFDocument, degrees } from "pdf-lib";
-import { buildExportPages } from "../utils/pdfPageSelection";
 import { Toaster, toast } from "sonner";
+import { buildExportPages } from "../utils/pdfPageSelection";
+import { buildTransformedPdf } from "../utils/pdfPageTransforms";
 import { motion } from "framer-motion";
 import {
   RotateCcw,
@@ -199,40 +199,19 @@ const transformAndDownload = async () => {
   try {
     const arrayBuffer = await file.arrayBuffer();
 
-    const originalPdfDoc = await PDFDocument.load(arrayBuffer);
-    const newPdfDoc = await PDFDocument.create();
-
     const exportPages = buildExportPages(
       previews,
-      originalPdfDoc.getPageCount(),
+      totalPages ?? previews.length,
       removedPageNumbers,
     );
-    const total = exportPages.length;
-
-    for (let i = 0; i < exportPages.length; i++) {
-      const previewItem = exportPages[i];
-
-      const originalIndex = previewItem.originalPageNum - 1;
-
-      const [copiedPage] = await newPdfDoc.copyPages(
-        originalPdfDoc,
-        [originalIndex]
-      );
 
-      const shouldTransform =
-        scope === "all" ||
-        selectedPreviewPages.includes(previewItem.originalPageNum);
-
-      if (shouldTransform) {
-        copiedPage.setRotation(degrees(previewItem.currentRotation));
-      }
-
-      newPdfDoc.addPage(copiedPage);
-
-      setProgress(Math.round(((i + 1) / total) * 100));
-    }
-
-    const pdfBytes = await newPdfDoc.save();
+    const pdfBytes = await buildTransformedPdf(
+      arrayBuffer,
+      exportPages,
+      (originalPageNum) =>
+        scope === "all" || selectedPreviewPages.includes(originalPageNum),
+      setProgress,
+    );
 
     const blob = new Blob([new Uint8Array(pdfBytes)], {
       type: "application/pdf",