chore: import upstream snapshot with attribution

server/routes/sessions.py

@@ -0,0 +1,83 @@
+import re
+import shutil
+import tempfile
+from pathlib import Path
+
+from fastapi import APIRouter, HTTPException
+from fastapi.responses import FileResponse
+from starlette.background import BackgroundTask
+
+from server.settings import WARE_HOUSE_DIR
+from utils.exceptions import ResourceNotFoundError, ValidationError
+from utils.structured_logger import get_server_logger, LogType
+
+router = APIRouter()
+
+
+@router.get("/api/sessions/{session_id}/download")
+async def download_session(session_id: str):
+    try:
+        if not re.match(r"^[a-zA-Z0-9_-]+$", session_id):
+            logger = get_server_logger()
+            logger.log_security_event(
+                "INVALID_SESSION_ID_FORMAT",
+                f"Invalid session_id format: {session_id}",
+                details={"received_session_id": session_id},
+            )
+            raise ValidationError(
+                "Invalid session_id: only letters, digits, underscores, and hyphens are allowed",
+                field="session_id",
+            )
+
+        dir_name = f"session_{session_id}"
+        session_path = WARE_HOUSE_DIR / dir_name
+
+        if not session_path.exists() or not session_path.is_dir():
+            raise ResourceNotFoundError(
+                "Session directory not found",
+                resource_type="session",
+                resource_id=session_id,
+            )
+
+        with tempfile.NamedTemporaryFile(delete=False, suffix=".zip") as tmp_file:
+            zip_path = Path(tmp_file.name)
+
+        archive_base = zip_path.with_suffix("")
+        try:
+            shutil.make_archive(str(archive_base), "zip", root_dir=WARE_HOUSE_DIR, base_dir=dir_name)
+        except Exception as exc:
+            if zip_path.exists():
+                zip_path.unlink()
+            logger = get_server_logger()
+            logger.log_exception(exc, f"Failed to create zip archive for session: {session_id}")
+            raise HTTPException(status_code=500, detail="Failed to create zip archive")
+
+        logger = get_server_logger()
+        logger.info(
+            "Session download prepared",
+            log_type=LogType.WORKFLOW,
+            session_id=session_id,
+            archive_path=str(zip_path),
+        )
+
+        def cleanup_zip():
+            if zip_path.exists():
+                zip_path.unlink()
+
+        return FileResponse(
+            path=zip_path,
+            filename=f"{dir_name}.zip",
+            media_type="application/zip",
+            headers={"Content-Disposition": f"attachment; filename={dir_name}.zip"},
+            background=BackgroundTask(cleanup_zip),
+        )
+    except ValidationError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    except ResourceNotFoundError:
+        raise HTTPException(status_code=404, detail="Session directory not found")
+    except HTTPException:
+        raise
+    except Exception as exc:
+        logger = get_server_logger()
+        logger.log_exception(exc, f"Unexpected error during session download: {session_id}")
+        raise HTTPException(status_code=500, detail="Failed to download session")