fix(files): handle empty json uploads safely (#434)

* fix(files): handle empty json uploads safely

* fix(files): normalize invalid json upload errors

* fix(files): restore file processing error import

---------

Co-authored-by: LRRuan <lrruan@users.noreply.github.com>

src/utils/files.py

@@ -10,7 +10,11 @@ from sqlalchemy.ext.asyncio import AsyncSession
 
 from src import schemas
 from src.config import settings
-from src.exceptions import FileProcessingError, UnsupportedFileTypeError
+from src.exceptions import (
+    FileProcessingError,
+    UnsupportedFileTypeError,
+    ValidationException,
+)
 from src.schemas import Message
 
 logger = logging.getLogger(__name__)
@@ -58,7 +62,19 @@ class JSONProcessor:
     async def extract_text(self, content: bytes) -> str:
         import json
 
-        data = json.loads(content.decode("utf-8"))
+        try:
+            decoded_content = content.decode("utf-8")
+        except UnicodeDecodeError as exc:
+            raise ValidationException("JSON uploads must be UTF-8 encoded") from exc
+
+        if not decoded_content.strip():
+            return ""
+
+        try:
+            data = json.loads(decoded_content)
+        except json.JSONDecodeError as exc:
+            raise ValidationException("Uploaded JSON is invalid") from exc
+
         # Convert JSON to readable text format
         return json.dumps(data, ensure_ascii=False)
 

tests/routes/test_files.py

@@ -134,6 +134,33 @@ async def test_create_messages_with_json_file(
     assert message["session_id"] == session_name
 
 
+@pytest.mark.asyncio
+async def test_create_messages_with_empty_json_file(
+    client: TestClient,
+    db_session: AsyncSession,
+    sample_data: tuple[Workspace, Peer],
+):
+    """Test that empty JSON uploads do not crash and create empty content."""
+    test_workspace, test_peer = sample_data
+
+    test_session = await _create_test_session(db_session, test_workspace)
+    session_name = test_session.name
+
+    file_data = io.BytesIO(b"")
+    files = {"file": ("empty.json", file_data, "application/json")}
+    form_data = {"peer_id": test_peer.name}
+
+    url = _get_upload_url(test_workspace.name, session_name)
+    response = client.post(url, files=files, data=form_data)
+
+    assert response.status_code == 201
+    data = response.json()
+    assert len(data) == 1
+    assert data[0]["content"] == ""
+    assert data[0]["peer_id"] == test_peer.name
+    assert data[0]["session_id"] == session_name
+
+
 @pytest.mark.asyncio
 async def test_create_messages_with_unsupported_file_type(
     client: TestClient,

tests/utils/test_files.py

@@ -0,0 +1,39 @@
+import json
+
+import pytest
+
+from src.exceptions import ValidationException
+from src.utils.files import JSONProcessor
+
+
+@pytest.mark.asyncio
+async def test_json_processor_returns_empty_string_for_blank_content():
+    processor = JSONProcessor()
+
+    assert await processor.extract_text(b"") == ""
+    assert await processor.extract_text(b"   \n\t") == ""
+
+
+@pytest.mark.asyncio
+async def test_json_processor_preserves_valid_json_behavior():
+    processor = JSONProcessor()
+
+    result = await processor.extract_text(b'{"name": "test", "count": 1}')
+
+    assert json.loads(result) == {"name": "test", "count": 1}
+
+
+@pytest.mark.asyncio
+async def test_json_processor_rejects_non_utf8_content():
+    processor = JSONProcessor()
+
+    with pytest.raises(ValidationException, match="UTF-8"):
+        await processor.extract_text(b"\xff\xfe\x00{")
+
+
+@pytest.mark.asyncio
+async def test_json_processor_rejects_invalid_json_content():
+    processor = JSONProcessor()
+
+    with pytest.raises(ValidationException, match="invalid"):
+        await processor.extract_text(b'{"name": }')