Update iot_ext_item_data_builder.py for Decimal serialization in JSON (#33)

* Update iot_ext_item_data_builder.py for Decimal serialization in JSON

* Update iot_ext_item_data_builder.py

* Update iot_ext_item_data_builder.py

Author: bieli

src/builders/iot_ext_item_data_builder.py

@@ -1,4 +1,5 @@
 import json
+import decimal
 from decimal import Decimal
 from typing import List, Optional
 
@@ -12,6 +13,21 @@
 from src.types.metric_data_item import MetricValueType, MetricDataItem
 
 
+class fakefloat(float):
+    def __init__(self, value):
+        self._value = value
+
+    def __repr__(self):
+        return str(self._value)
+
+
+def defaultencode(o):
+    if isinstance(o, Decimal):
+        # Subclass float with custom repr?
+        return fakefloat(o)
+    raise TypeError(repr(o) + " is not JSON serializable")
+
+
 class IoTextItemDataBuilder:
     def __init__(
         self, timestamp: int, device_name: str, add_crc16: bool = False
@@ -80,7 +96,7 @@ def iotext_to_json_one_object(iotext_msg) -> str:
             else:
                 data_row[item.kind] = item.name
             data_row.update(data_row)
-        return json.dumps(data_row)
+        return json.dumps(data_row, default=defaultencode)
 
     @staticmethod
     def to_json_from_iotext_struct(