Handle recursively serializing a dataclasses as a dictionary. (mobilityhouse#547)

see issue mobilityhouse#255

Author: Jared-Newell-Mobility

CHANGELOG.md

@@ -1,5 +1,6 @@
 # Change log
 
+- [#547](https://github.com/mobilityhouse/ocpp/pull/547) Feat: Handle recursively serializing a dataclasses as a dictionary Thanks [@MacDue](https://github.com/MacDue)
 - [#601](https://github.com/mobilityhouse/ocpp/issues/601) Fix case conversion for soc in non "State of Charge" context
 - [#523](https://github.com/mobilityhouse/ocpp/issues/523) The serialisation of soc to SoC should not occur in camel case if it is existing at the beginning of a field
 - [#515](https://github.com/mobilityhouse/ocpp/issues/515) Update Readthedocs configuration

ocpp/charge_point.py

@@ -4,8 +4,8 @@
 import re
 import time
 import uuid
-from dataclasses import asdict
-from typing import Dict, List, Union
+from dataclasses import Field, asdict, is_dataclass
+from typing import Any, Dict, List, Union, get_args, get_origin
 
 from ocpp.exceptions import NotImplementedError, NotSupportedError, OCPPError
 from ocpp.messages import Call, MessageType, unpack, validate_payload
@@ -73,6 +73,71 @@ def snake_to_camel_case(data):
     return data
 
 
+def _is_dataclass_instance(input: Any) -> bool:
+    """Verify if given `input` is a dataclass."""
+    return is_dataclass(input) and not isinstance(input, type)
+
+
+def _is_optional_field(field: Field) -> bool:
+    """Verify if given `field` allows `None` as value.
+
+    The fields `schema` and `host` on the following class would return `False`.
+    While the fields `post` and `query` return `True`.
+
+        @dataclass
+        class URL:
+            schema: str,
+            host: str,
+            post: Optional[str],
+            query: Union[None, str]
+
+    """
+    return get_origin(field.type) is Union and type(None) in get_args(field.type)
+
+
+def serialize_as_dict(dataclass):
+    """Serialize the given `dataclass` as a `dict` recursively.
+
+    @dataclass
+    class StatusInfoType:
+        reason_code: str
+        additional_info: Optional[str] = None
+
+    with_additional_info = StatusInfoType(
+        reason="Unknown",
+        additional_info="More details"
+    )
+
+    assert serialize_as_dict(with_additional_info) == {
+        'reason': 'Unknown',
+        'additional_info': 'More details',
+    }
+
+    without_additional_info = StatusInfoType(reason="Unknown")
+
+    assert serialize_as_dict(with_additional_info) == {
+        'reason': 'Unknown',
+        'additional_info': None,
+    }
+
+    """
+    serialized = asdict(dataclass)
+
+    for field in dataclass.__dataclass_fields__.values():
+
+        value = getattr(dataclass, field.name)
+        if _is_dataclass_instance(value):
+            serialized[field.name] = serialize_as_dict(value)
+            continue
+
+        if isinstance(value, list):
+            for item in value:
+                if _is_dataclass_instance(item):
+                    serialized[field.name] = [serialize_as_dict(item)]
+
+    return serialized
+
+
 def remove_nones(data: Union[List, Dict]) -> Union[List, Dict]:
     if isinstance(data, dict):
         return {k: remove_nones(v) for k, v in data.items() if v is not None}
@@ -246,7 +311,7 @@ async def _handle_call(self, msg):
 
             return
 
-        temp_response_payload = asdict(response)
+        temp_response_payload = serialize_as_dict(response)
 
         # Remove nones ensures that we strip out optional arguments
         # which were not set and have a default value of None
@@ -308,7 +373,7 @@ async def call(self, payload, suppress=True, unique_id=None):
         CallError.
 
         """
-        camel_case_payload = snake_to_camel_case(asdict(payload))
+        camel_case_payload = snake_to_camel_case(serialize_as_dict(payload))
 
         unique_id = (
             unique_id if unique_id is not None else str(self._unique_id_generator())

tests/test_charge_point.py

@@ -2,7 +2,12 @@
 
 import pytest
 
-from ocpp.charge_point import camel_to_snake_case, remove_nones, snake_to_camel_case
+from ocpp.charge_point import (
+    camel_to_snake_case,
+    remove_nones,
+    serialize_as_dict,
+    snake_to_camel_case,
+)
 from ocpp.messages import Call
 from ocpp.routing import after, create_route_map, on
 from ocpp.v16 import ChargePoint as cp_16
@@ -11,8 +16,15 @@
 from ocpp.v16.datatypes import MeterValue, SampledValue
 from ocpp.v16.enums import Action, RegistrationStatus
 from ocpp.v201 import ChargePoint as cp_201
-from ocpp.v201.call import SetNetworkProfile
-from ocpp.v201.datatypes import NetworkConnectionProfileType
+from ocpp.v201.call import GetVariables as v201GetVariables
+from ocpp.v201.call import SetNetworkProfile as v201SetNetworkProfile
+from ocpp.v201.datatypes import (
+    ComponentType,
+    EVSEType,
+    GetVariableDataType,
+    NetworkConnectionProfileType,
+    VariableType,
+)
 from ocpp.v201.enums import OCPPInterfaceType, OCPPTransportType, OCPPVersionType
 
 
@@ -72,7 +84,7 @@ def test_camel_to_snake_case(test_input, expected):
     [
         ({"transaction_id": "74563478"}, {"transactionId": "74563478"}),
         ({"full_soc": 100}, {"fullSoC": 100}),
-        ({"soc_limit_reached": 200}, {"SOCLimitReached": 200}),
+        ({"soc_limit_reached": 200}, {"SoCLimitReached": 200}),
         ({"ev_min_v2x_energy_request": 200}, {"evMinV2XEnergyRequest": 200}),
         ({"v2x_charging_ctrlr": 200}, {"v2xChargingCtrlr": 200}),
         ({"web_socket_ping_interval": 200}, {"webSocketPingInterval": 200}),
@@ -125,7 +137,9 @@ def test_nested_remove_nones():
         apn=None,
     )
 
-    payload = SetNetworkProfile(configuration_slot=1, connection_data=connection_data)
+    payload = v201SetNetworkProfile(
+        configuration_slot=1, connection_data=connection_data
+    )
     payload = asdict(payload)
 
     assert expected_payload == remove_nones(payload)
@@ -246,6 +260,50 @@ def test_remove_nones_with_list_of_strings():
     }
 
 
+def test_serialize_as_dict():
+    """
+    Test recursively serializing a dataclasses as a dictionary.
+    """
+    # Setup
+    expected = camel_to_snake_case(
+        {
+            "getVariableData": [
+                {
+                    "component": {
+                        "name": "Component",
+                        "instance": None,
+                        "evse": {
+                            "id": 1,
+                            "connectorId": None,
+                        },
+                    },
+                    "variable": {
+                        "name": "Variable",
+                        "instance": None,
+                    },
+                    "attributeType": None,
+                }
+            ],
+            "customData": None,
+        }
+    )
+
+    payload = v201GetVariables(
+        get_variable_data=[
+            GetVariableDataType(
+                component=ComponentType(
+                    name="Component",
+                    evse=EVSEType(id=1),
+                ),
+                variable=VariableType(name="Variable"),
+            )
+        ]
+    )
+
+    # Execute / Assert
+    assert serialize_as_dict(payload) == expected
+
+
 @pytest.mark.asyncio
 async def test_call_unique_id_added_to_handler_args_correctly(connection):
     """