mirror of
https://github.com/freedomofpress/dangerzone.git
synced 2025-04-28 18:02:38 +02:00
389 lines
14 KiB
Python
389 lines
14 KiB
Python
#!/usr/bin/env python3
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"""
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Here are the steps, with progress bar percentages for each step:
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document_to_pixels
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- 0%-3%: Convert document into a PDF (skipped if the input file is a PDF)
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- 3%-5%: Split PDF into individual pages, and count those pages
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- 5%-50%: Convert each page into pixels (each page takes 45/n%, where n is the number of pages)
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pixels_to_pdf:
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- 50%-95%: Convert each page of pixels into a PDF (each page takes 45/n%, where n is the number of pages)
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- 95%-100%: Compress the final PDF
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"""
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import glob
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import json
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import os
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import shutil
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import subprocess
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import sys
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from typing import Dict, List, Optional
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import magic
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from PIL import Image
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# timeout in seconds for any single subprocess
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DEFAULT_TIMEOUT: float = 120
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# timeout in seconds for compressing a single page of the final document
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COMPRESSION_TIMEOUT: float = 10
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def run_command(
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args: List[str],
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*,
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error_message: str,
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timeout_message: str,
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timeout: float = DEFAULT_TIMEOUT,
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) -> subprocess.CompletedProcess:
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"""
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Runs a command and returns the result.
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:raises RuntimeError: if the process returns a non-zero exit status
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:raises TimeoutError: if the process times out
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"""
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try:
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return subprocess.run(
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args,
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stdout=subprocess.DEVNULL,
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stderr=subprocess.DEVNULL,
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timeout=timeout,
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check=True,
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)
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except subprocess.CalledProcessError as e:
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raise RuntimeError(error_message) from e
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except subprocess.TimeoutExpired as e:
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raise TimeoutError(timeout_message) from e
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class DangerzoneConverter:
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def __init__(self) -> None:
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self.percentage: float = 0.0
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def document_to_pixels(self) -> None:
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conversions: Dict[str, Dict[str, Optional[str]]] = {
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# .pdf
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"application/pdf": {"type": None},
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# .docx
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"application/vnd.openxmlformats-officedocument.wordprocessingml.document": {
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"type": "libreoffice",
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"libreoffice_output_filter": "writer_pdf_Export",
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},
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# .doc
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"application/msword": {
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"type": "libreoffice",
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"libreoffice_output_filter": "writer_pdf_Export",
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},
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# .docm
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"application/vnd.ms-word.document.macroEnabled.12": {
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"type": "libreoffice",
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"libreoffice_output_filter": "writer_pdf_Export",
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},
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# .xlsx
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"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet": {
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"type": "libreoffice",
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"libreoffice_output_filter": "calc_pdf_Export",
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},
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# .xls
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"application/vnd.ms-excel": {
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"type": "libreoffice",
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"libreoffice_output_filter": "calc_pdf_Export",
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},
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# .pptx
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"application/vnd.openxmlformats-officedocument.presentationml.presentation": {
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"type": "libreoffice",
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"libreoffice_output_filter": "impress_pdf_Export",
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},
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# .ppt
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"application/vnd.ms-powerpoint": {
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"type": "libreoffice",
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"libreoffice_output_filter": "impress_pdf_Export",
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},
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# .odt
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"application/vnd.oasis.opendocument.text": {
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"type": "libreoffice",
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"libreoffice_output_filter": "writer_pdf_Export",
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},
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# .odg
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"application/vnd.oasis.opendocument.graphics": {
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"type": "libreoffice",
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"libreoffice_output_filter": "impress_pdf_Export",
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},
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# .odp
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"application/vnd.oasis.opendocument.presentation": {
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"type": "libreoffice",
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"libreoffice_output_filter": "impress_pdf_Export",
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},
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# .ops
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"application/vnd.oasis.opendocument.spreadsheet": {
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"type": "libreoffice",
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"libreoffice_output_filter": "calc_pdf_Export",
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},
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# .jpg
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"image/jpeg": {"type": "convert"},
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# .gif
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"image/gif": {"type": "convert"},
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# .png
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"image/png": {"type": "convert"},
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# .tif
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"image/tiff": {"type": "convert"},
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"image/x-tiff": {"type": "convert"},
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}
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# Detect MIME type
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mime = magic.Magic(mime=True)
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mime_type = mime.from_file("/tmp/input_file")
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# Validate MIME type
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if mime_type not in conversions:
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raise ValueError("The document format is not supported")
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# Convert input document to PDF
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conversion = conversions[mime_type]
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if conversion["type"] is None:
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pdf_filename = "/tmp/input_file"
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elif conversion["type"] == "libreoffice":
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self.update_progress("Converting to PDF using LibreOffice")
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args = [
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"libreoffice",
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"--headless",
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"--convert-to",
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f"pdf:{conversion['libreoffice_output_filter']}",
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"--outdir",
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"/tmp",
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"/tmp/input_file",
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]
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run_command(
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args,
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error_message="Conversion to PDF with LibreOffice failed",
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timeout_message=f"Error converting document to PDF, LibreOffice timed out after {DEFAULT_TIMEOUT} seconds",
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)
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pdf_filename = "/tmp/input_file.pdf"
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elif conversion["type"] == "convert":
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self.update_progress("Converting to PDF using GraphicsMagick")
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args = [
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"gm",
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"convert",
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"/tmp/input_file",
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"/tmp/input_file.pdf",
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]
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run_command(
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args,
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error_message="Conversion to PDF with GraphicsMagick failed",
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timeout_message=f"Error converting document to PDF, GraphicsMagick timed out after {DEFAULT_TIMEOUT} seconds",
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)
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pdf_filename = "/tmp/input_file.pdf"
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else:
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raise ValueError(
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f"Invalid conversion type {conversion['type']} for MIME type {mime_type}"
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)
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self.percentage += 3
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# Separate PDF into pages
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self.update_progress("Separating document into pages")
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args = ["pdftk", pdf_filename, "burst", "output", "/tmp/page-%d.pdf"]
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run_command(
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args,
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error_message="Separating document into pages failed",
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timeout_message=f"Error separating document into pages, pdftk timed out after {DEFAULT_TIMEOUT} seconds",
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)
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page_filenames = glob.glob("/tmp/page-*.pdf")
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self.percentage += 2
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# Convert to RGB pixel data
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percentage_per_page = 45.0 / len(page_filenames)
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for page in range(1, len(page_filenames) + 1):
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pdf_filename = f"/tmp/page-{page}.pdf"
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png_filename = f"/tmp/page-{page}.png"
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rgb_filename = f"/tmp/page-{page}.rgb"
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width_filename = f"/tmp/page-{page}.width"
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height_filename = f"/tmp/page-{page}.height"
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filename_base = f"/tmp/page-{page}"
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self.update_progress(
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f"Converting page {page}/{len(page_filenames)} to pixels"
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)
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# Convert to png
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run_command(
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["pdftocairo", pdf_filename, "-png", "-singlefile", filename_base],
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error_message="Conversion from PDF to PNG failed",
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timeout_message=f"Error converting from PDF to PNG, pdftocairo timed out after {DEFAULT_TIMEOUT} seconds",
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)
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# Save the width and height
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with Image.open(png_filename, "r") as im:
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width, height = im.size
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with open(width_filename, "w") as f:
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f.write(str(width))
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with open(height_filename, "w") as f:
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f.write(str(height))
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# Convert to RGB pixels
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run_command(
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[
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"gm",
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"convert",
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png_filename,
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"-depth",
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"8",
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f"rgb:{rgb_filename}",
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],
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error_message="Conversion from PNG to RGB failed",
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timeout_message=f"Error converting from PNG to pixels, convert timed out after {DEFAULT_TIMEOUT} seconds",
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)
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# Delete the png
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os.remove(png_filename)
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self.percentage += percentage_per_page
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self.update_progress("Converted document to pixels")
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# Move converted files into /dangerzone
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for filename in (
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glob.glob("/tmp/page-*.rgb")
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+ glob.glob("/tmp/page-*.width")
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+ glob.glob("/tmp/page-*.height")
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):
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shutil.move(filename, "/dangerzone")
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def pixels_to_pdf(self) -> None:
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self.percentage = 50.0
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num_pages = len(glob.glob("/dangerzone/page-*.rgb"))
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# Convert RGB files to PDF files
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percentage_per_page = 45.0 / num_pages
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for page in range(1, num_pages + 1):
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filename_base = f"/dangerzone/page-{page}"
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rgb_filename = f"{filename_base}.rgb"
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width_filename = f"{filename_base}.width"
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height_filename = f"{filename_base}.height"
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png_filename = f"/tmp/page-{page}.png"
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ocr_filename = f"/tmp/page-{page}"
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pdf_filename = f"/tmp/page-{page}.pdf"
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with open(width_filename) as f:
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width = f.read().strip()
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with open(height_filename) as f:
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height = f.read().strip()
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if os.environ.get("OCR") == "1": # OCR the document
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self.update_progress(
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f"Converting page {page}/{num_pages} from pixels to searchable PDF"
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)
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run_command(
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[
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"gm",
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"convert",
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"-size",
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f"{width}x{height}",
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"-depth",
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"8",
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f"rgb:{rgb_filename}",
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f"png:{png_filename}",
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],
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error_message=f"Page {page}/{num_pages} conversion to PNG failed",
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timeout_message=f"Error converting pixels to PNG, convert timed out after {DEFAULT_TIMEOUT} seconds",
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)
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run_command(
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[
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"tesseract",
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png_filename,
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ocr_filename,
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"-l",
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os.environ.get("OCR_LANGUAGE"), # type: ignore
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"--dpi",
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"70",
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"pdf",
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],
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error_message=f"Page {page}/{num_pages} OCR failed",
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timeout_message=f"Error converting PNG to searchable PDF, tesseract timed out after {DEFAULT_TIMEOUT} seconds",
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)
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else: # Don't OCR
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self.update_progress(
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f"Converting page {page}/{num_pages} from pixels to PDF"
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)
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run_command(
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[
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"gm",
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"convert",
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"-size",
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f"{width}x{height}",
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"-depth",
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"8",
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f"rgb:{rgb_filename}",
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f"pdf:{pdf_filename}",
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],
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error_message=f"Page {page}/{num_pages} conversion to PDF failed",
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timeout_message=f"Error converting RGB to PDF, convert timed out after {DEFAULT_TIMEOUT} seconds",
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)
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self.percentage += percentage_per_page
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# Merge pages into a single PDF
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self.update_progress(f"Merging {num_pages} pages into a single PDF")
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args = ["pdfunite"]
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for page in range(1, num_pages + 1):
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args.append(f"/tmp/page-{page}.pdf")
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args.append(f"/tmp/safe-output.pdf")
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run_command(
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args,
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error_message="Merging pages into a single PDF failed",
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timeout_message=f"Error merging pages into a single PDF, pdfunite timed out after {DEFAULT_TIMEOUT} seconds",
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)
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self.percentage += 2
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# Compress
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self.update_progress("Compressing PDF")
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compress_timeout = num_pages * COMPRESSION_TIMEOUT
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run_command(
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["ps2pdf", "/tmp/safe-output.pdf", "/tmp/safe-output-compressed.pdf"],
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timeout_message=f"Error compressing PDF, ps2pdf timed out after {compress_timeout} seconds",
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error_message="Compressing PDF failed",
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timeout=compress_timeout,
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)
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self.percentage = 100.0
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self.update_progress("Safe PDF created")
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# Move converted files into /safezone
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shutil.move("/tmp/safe-output.pdf", "/safezone")
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shutil.move("/tmp/safe-output-compressed.pdf", "/safezone")
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def update_progress(self, text: str, *, error: bool = False) -> None:
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print(
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json.dumps(
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{"error": error, "text": text, "percentage": int(self.percentage)}
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)
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)
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sys.stdout.flush()
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def main() -> int:
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if len(sys.argv) != 2:
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print(f"Usage: {sys.argv[0]} [document-to-pixels]|[pixels-to-pdf]")
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return -1
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converter = DangerzoneConverter()
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try:
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if sys.argv[1] == "document-to-pixels":
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converter.document_to_pixels()
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elif sys.argv[1] == "pixels-to-pdf":
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converter.pixels_to_pdf()
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except (RuntimeError, TimeoutError, ValueError) as e:
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converter.update_progress(str(e), error=True)
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return 1
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else:
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return 0 # Success!
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if __name__ == "__main__":
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sys.exit(main())
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