Fix a bug where some NaN values could leak into the JSON output, causing it to be invalid. Created a new safe_json_dumps method since we would otherwise now be providing multiple parameters all over the code

core/utils.py

@@ -1,8 +1,11 @@
-def serialize_everything(obj):
-    """Convert objects to serialisable things. Used by JSON serialiser as a default when it encounters unserializable things.
-    Just converts objects to dict. Try to avoid doing anything clever here when serialising spots, because we also need
-    to receive spots without complex handling."""
-    return obj.__dict__
+import simplejson
+
+
+def safe_json_dumps(obj):
+    """Safe version of json.dumps that also converts objects to dicts so they can be output, and ignores NaN floats
+    which are invalid in JSON."""
+
+    return simplejson.dumps(obj, ensure_ascii=False, ignore_nan=True, default=lambda o: o.__dict__)
 
 
 def empty_queue(q):