?_json_infinity=1 for handling Infinity/-Infinity - fixes #332

datasette/utils.py

@@ -864,3 +864,15 @@ class LimitedWriter:
                 self.limit_bytes
             ))
         self.writer.write(bytes)
+
+
+_infinities = {float("inf"), float("-inf")}
+
+
+def remove_infinites(row):
+    if any((c in _infinities) if isinstance(c, float) else 0 for c in row):
+        return [
+            None if (isinstance(c, float) and c in _infinities) else c
+            for c in row
+        ]
+    return row

datasette/views/base.py

@@ -20,8 +20,10 @@ from datasette.utils import (
     path_from_row_pks,
     path_with_added_args,
     path_with_format,
+    remove_infinites,
     resolve_table_and_format,
-    to_css_class
+    to_css_class,
+    value_as_boolean,
 )
 
 ureg = pint.UnitRegistry()
@@ -334,6 +336,12 @@ class BaseView(RenderMixin):
                     data["rows"], data["columns"], json_cols,
                 )
 
+            # unless _json_infinity=1 requested, replace infinity with None
+            if "rows" in data and not value_as_boolean(
+                request.args.get("_json_infinity", "0")
+            ):
+                data["rows"] = [remove_infinites(row) for row in data["rows"]]
+
             # Deal with the _shape option
             shape = request.args.get("_shape", "arrays")
             if shape == "arrayfirst":