Function download_backup

apps/backups/api_views.py:156–231

Download a backup file. Requires either: - Valid admin authentication, OR - Valid download_token query parameter

(request, filename)

@api_view(["GET"])
@permission_classes([AllowAny])
def download_backup(request, filename):
    """Download a backup file.

    Requires either:
    - Valid admin authentication, OR
    - Valid download_token query parameter
    """
    # Check for token-based auth (avoids CORS preflight issues)
    token = request.query_params.get("token")
    if token:
        if not _verify_task_token(filename, token):
            return Response(
                {"detail": "Invalid download token"},
                status=status.HTTP_403_FORBIDDEN,
            )
    else:
        # Fall back to admin auth check
        if not request.user.is_authenticated or getattr(request.user, 'user_level', 0) < 10:
            return Response(
                {"detail": "Authentication required"},
                status=status.HTTP_401_UNAUTHORIZED,
            )

    try:
        # Security: prevent path traversal by checking for suspicious characters
        if ".." in filename or "/" in filename or "\\" in filename:
            raise Http404("Invalid filename")

        backup_dir = services.get_backup_dir()
        backup_file = (backup_dir / filename).resolve()

        # Security: ensure the resolved path is still within backup_dir
        if not str(backup_file).startswith(str(backup_dir.resolve())):
            raise Http404("Invalid filename")

        if not backup_file.exists() or not backup_file.is_file():
            raise Http404("Backup file not found")

        file_size = backup_file.stat().st_size

        # Use X-Accel-Redirect for nginx (AIO container) - nginx serves file directly
        # Fall back to streaming for non-nginx deployments
        use_nginx_accel = os.environ.get("USE_NGINX_ACCEL", "").lower() == "true"
        logger.info(f"[DOWNLOAD] File: {filename}, Size: {file_size}, USE_NGINX_ACCEL: {use_nginx_accel}")

        if use_nginx_accel:
            # X-Accel-Redirect: Django returns immediately, nginx serves file
            logger.info(f"[DOWNLOAD] Using X-Accel-Redirect: /protected-backups/{filename}")
            response = HttpResponse()
            response["X-Accel-Redirect"] = f"/protected-backups/{filename}"
            response["Content-Type"] = "application/zip"
            response["Content-Length"] = file_size
            response["Content-Disposition"] = f'attachment; filename="{filename}"'
            return response
        else:
            # Streaming fallback for non-nginx deployments
            logger.info(f"[DOWNLOAD] Using streaming fallback (no nginx)")
            def file_iterator(file_path, chunk_size=2 * 1024 * 1024):