policies/expression: add Expression based policy

passbook/policies/expression/api.py

@@ -0,0 +1,21 @@
+"""Expression Policy API"""
+from rest_framework.serializers import ModelSerializer
+from rest_framework.viewsets import ModelViewSet
+
+from passbook.policies.expression.models import ExpressionPolicy
+from passbook.policies.forms import GENERAL_SERIALIZER_FIELDS
+
+
+class ExpressionPolicySerializer(ModelSerializer):
+    """Group Membership Policy Serializer"""
+
+    class Meta:
+        model = ExpressionPolicy
+        fields = GENERAL_SERIALIZER_FIELDS + ["expression"]
+
+
+class ExpressionPolicyViewSet(ModelViewSet):
+    """Source Viewset"""
+
+    queryset = ExpressionPolicy.objects.all()
+    serializer_class = ExpressionPolicySerializer