Add model value serializer.

Author: adamghill

django_unicorn/components/__init__.py

@@ -1,3 +1,4 @@
+from .mixins import ModelValueMixin
 from .typing import QuerySetType
 from .unicorn_view import UnicornField, UnicornView
 from .updaters import HashUpdate, LocationUpdate, PollUpdate
@@ -10,4 +11,5 @@
     "HashUpdate",
     "LocationUpdate",
     "PollUpdate",
+    "ModelValueMixin",
 ]

django_unicorn/components/mixins.py

@@ -0,0 +1,11 @@
+from django_unicorn.serializer import model_value
+
+
+class ModelValueMixin:
+    """
+    Adds a `value` method to a model similar to `QuerySet.values(*fields)` which serializes
+    a model into a dictionary with the fields as specified in the `fields` argument.
+    """
+
+    def value(self, *fields):
+        return model_value(self, *fields)

django_unicorn/serializer.py

@@ -197,3 +197,21 @@ def loads(str: str) -> dict:
         return orjson.loads(str)
     except orjson.JSONDecodeError as e:
         raise JSONDecodeError from e
+
+
+def model_value(model: Model, *fields: str):
+    """
+    Serializes a model into a dictionary with the fields as specified in the `fields` argument.
+    """
+
+    model_data = {}
+    model_dict = _get_model_dict(model)
+
+    if not fields:
+        return model_dict
+
+    for field in fields:
+        if field in model_dict:
+            model_data[field] = model_dict[field]
+
+    return model_data

tests/serializer/test_model_value.py

@@ -0,0 +1,66 @@
+from django.db import models
+
+from django_unicorn.components import ModelValueMixin
+from django_unicorn.serializer import model_value
+from example.coffee.models import Flavor
+
+
+def test_model_value_all_fields():
+    flavor = Flavor(name="flavor-1")
+
+    expected = {
+        "date": None,
+        "datetime": None,
+        "decimal_value": None,
+        "duration": None,
+        "float_value": None,
+        "name": flavor.name,
+        "label": "",
+        "parent": None,
+        "pk": None,
+        "time": None,
+        "uuid": str(flavor.uuid),
+    }
+
+    actual = model_value(flavor)
+
+    assert expected == actual
+
+
+def test_model_value_one_field():
+    expected = {"name": "flavor-1"}
+
+    flavor = Flavor(name="flavor-1")
+    actual = model_value(flavor, "name")
+
+    assert expected == actual
+
+
+def test_model_value_multiple_field():
+    expected = {
+        "pk": 77,
+        "name": "flavor-1",
+    }
+
+    flavor = Flavor(name="flavor-1", id=77)
+    actual = model_value(flavor, "pk", "name")
+
+    assert expected == actual
+
+
+class FakeModel(ModelValueMixin, models.Model):
+    name = models.CharField(max_length=255)
+
+    class Meta:
+        app_label = "tests"
+
+
+def test_model_value_mixin():
+    test_model = FakeModel(name="test-model")
+    expected = {"name": test_model.name}
+
+    actual = test_model.value("name")
+    assert expected == actual
+
+    actual = model_value(test_model, "name")
+    assert expected == actual