Convert non-json-serializable properties to strings

Author: adamnsch

changelog.md

@@ -13,6 +13,7 @@
 ## Improvements
 
 * Allow for `Node` and `Relationship` inputs to be given as `camelCase` and `SCREAMING_SNAKE_CASE` (in addition to `snake_case`).
+* Convert non-json serializable properties to strings in the `render` method, instead of raising an error.
 
 
 ## Other changes

python-wrapper/src/neo4j_viz/nvl.py

@@ -3,6 +3,7 @@
 import json
 import uuid
 from importlib.resources import files
+from typing import Any, Union
 
 from IPython.display import HTML
 
@@ -40,11 +41,37 @@ def __init__(self) -> None:
         with screenshot_path.open("r", encoding="utf-8") as file:
             self.screenshot_svg = file.read()
 
-    def unsupported_field_type_error(self, e: TypeError, entity: str) -> Exception:
+    @staticmethod
+    def unsupported_field_type_error(e: TypeError, entity: str) -> Exception:
         if "not JSON serializable" in str(e):
             return ValueError(f"A field of a {entity} object is not supported: {str(e)}")
         return e
 
+    @staticmethod
+    def _serialize_entity(entity: Union[Node, Relationship]) -> dict[str, Any]:
+        try:
+            entity_dict = entity.to_dict()
+            json.dumps(entity_dict)
+            return entity_dict
+        except TypeError:
+            props_as_strings = {}
+            for k, v in entity_dict["properties"].items():
+                try:
+                    json.dumps(v)
+                except TypeError:
+                    props_as_strings[k] = str(v)
+            entity_dict["properties"].update(props_as_strings)
+
+            try:
+                json.dumps(entity_dict)
+                return entity_dict
+            except TypeError as e:
+                # This should never happen anymore, but just in case
+                if "not JSON serializable" in str(e):
+                    raise ValueError(f"A field of a {type(entity).__name__} object is not supported: {str(e)}")
+                else:
+                    raise e
+
     def render(
         self,
         nodes: list[Node],
@@ -54,14 +81,8 @@ def render(
         height: str,
         show_hover_tooltip: bool,
     ) -> HTML:
-        try:
-            nodes_json = json.dumps([node.to_dict() for node in nodes])
-        except TypeError as e:
-            raise self.unsupported_field_type_error(e, "node")
-        try:
-            rels_json = json.dumps([rel.to_dict() for rel in relationships])
-        except TypeError as e:
-            raise self.unsupported_field_type_error(e, "relationship")
+        nodes_json = json.dumps([self._serialize_entity(node) for node in nodes])
+        rels_json = json.dumps([self._serialize_entity(rel) for rel in relationships])
 
         render_options_json = json.dumps(render_options.to_dict())
         container_id = str(uuid.uuid4())

python-wrapper/tests/test_render.py

@@ -121,3 +121,20 @@ def test_render_warnings() -> None:
         "relationships. If you need these features, use the canvas renderer by setting the `renderer` parameter",
     ):
         VG.render(max_allowed_nodes=20_000, renderer=Renderer.WEB_GL)
+
+
+def test_render_non_json_serializable() -> None:
+    import datetime
+
+    nodes = [
+        Node(
+            id=0,
+            properties={
+                "non-json-serializable": datetime.datetime.now(),
+            },
+        )
+    ]
+
+    VG = VisualizationGraph(nodes=nodes, relationships=[])
+
+    VG.render()