Add DRF serializer fields.

staticmodel/django/rest_framework/serializers.py

@@ -0,0 +1,64 @@
+"""
+*********************************
+Django Rest Framework integration
+*********************************
+
+**Static Model** provides custom DRF serializer fields in the
+``staticmodel.django.rest_framework.serializers`` module:
+
+ * ``StaticModelCharField`` (sub-class of ``rest_framework.serializers.CharField``)
+ * ``StaticModelIntegerField`` (sub-class of ``rest_framework.serializers.IntegerField``)
+
+Currently, only a single field value is extracted from the static model
+instance when serializing. Support for serializing the entire instance
+as a nested dict will be added in the future.
+
+When deserializing, the single field value is looked up in the static model
+and the corresponding member is returned.
+
+All fields take the following keyword arguments in addition to the
+arguments taken by their respective parent classes:
+
+ * ``static_model``: The static model class associated with this field.
+ * ``lookup_field_name``: The static model field name that will be
+   returned during serialization and that will be used to lookup the
+   static model member when deserializing. Defaults to the first field
+   name in ``static_model._field_names``.
+"""
+from rest_framework import serializers
+from staticmodel import StaticModel
+
+
+class StaticModelFieldMixin(object):
+
+    def __init__(self, *args, **kwargs):
+        static_model = kwargs.pop('static_model', None)
+        if not static_model:
+            raise TypeError("Parameter 'static_model' is required")
+        if not issubclass(static_model, StaticModel):
+            raise TypeError("Parameter 'static_model' must be a StaticModel class")
+        self._static_model = static_model
+
+        lookup_field_name = kwargs.pop('lookup_field_name', None)
+        if lookup_field_name and lookup_field_name not in self._static_model._field_names:
+            raise ValueError("Parameter 'lookup_field' must be one of: {}".format(
+                ', '.join(self._static_model._field_names)))
+        if not lookup_field_name:
+            lookup_field_name = self._static_model._field_names[0]
+        self._lookup_field_name = lookup_field_name
+
+        super().__init__(*args, **kwargs)
+
+    def to_native(self, value):
+        return getattr(value, self._lookup_field_name)
+
+    def from_native(self, value):
+        return self._static_model.members.get(**{self._lookup_field_name: value})
+
+
+class StaticModelCharField(StaticModelFieldMixin, serializers.CharField):
+    pass
+
+
+class StaticModelIntegerField(StaticModelFieldMixin, serializers.IntegerField):
+    pass