Fix filedownload error

bbot/core/event/base.py

@@ -1648,6 +1648,8 @@ def make_event(
         When working within a module's `handle_event()`, use the instance method
         `self.make_event()` instead of calling this function directly.
     """
+    if not data:
+        raise ValidationError("No data provided")
 
     # allow tags to be either a string or an array
     if not tags:

bbot/modules/filedownload.py

@@ -146,7 +146,8 @@ async def download_file(self, url, content_type=None, source_event=None):
                 file_event = self.make_event(
                     {"path": str(file_destination)}, "FILESYSTEM", tags=["filedownload", "file"], parent=source_event
                 )
-                await self.emit_event(file_event)
+                if file_event is not None:
+                    await self.emit_event(file_event)
         self.urls_downloaded.add(hash(url))
 
     def make_filename(self, url, content_type=None):

bbot/test/test_step_1/test_events.py

@@ -611,6 +611,10 @@ async def test_events(events, helpers):
     assert str(parent_event_3.module) == "mymodule"
     assert str(parent_event_3.module_sequence) == "mymodule->mymodule->mymodule"
 
+    # event with no data
+    with pytest.raises(ValidationError):
+        event = scan.make_event(None, "DNS_NAME", parent=scan.root_event)
+
     await scan._cleanup()