#31 API basic implementation Refactor

* reorganizes code into proper api/utils/serializer subclasses to keep serialization logic away from regular view logic

api/utils/serializer.py

@@ -0,0 +1,76 @@
+"""
+Author: Michel Peltriaux
+Organization: Struktur- und Genehmigungsdirektion Nord, Rhineland-Palatinate, Germany
+Contact: michel.peltriaux@sgdnord.rlp.de
+Created on: 24.01.22
+
+"""
+from abc import abstractmethod
+
+
+class AbstractModelAPISerializer:
+    model = None
+    user = None
+    lookup = None
+    properties_data = None
+
+    class Meta:
+        abstract = True
+
+    def __init__(self, *args, **kwargs):
+        self.lookup = {
+            "id": None,  # must be set
+            "deleted__isnull": True,
+            "users__in": [],  # must be set
+        }
+        super().__init__(*args, **kwargs)
+
+    @abstractmethod
+    def model_to_geo_json(self, entry):
+        """ Defines the model as geo json
+
+        Args:
+            entry (): The found entry from the database
+
+        Returns:
+
+        """
+        raise NotImplementedError("Must be implemented in subclasses")
+
+    @abstractmethod
+    def extend_properties_data(self, entry):
+        """ Defines the 'properties' part of geo json
+
+        Args:
+            entry (): The found entry from the database
+
+        Returns:
+
+        """
+        raise NotImplementedError("Must be implemented in subclasses")
+
+    @abstractmethod
+    def prepare_lookup(self, _id, user):
+        """ Updates lookup dict for db fetching
+
+        Args:
+            _id (str): The object's id
+            user (User): The user requesting for
+
+        Returns:
+
+        """
+        self.lookup["id"] = _id
+        self.lookup["users__in"] = [user]
+
+    def fetch_and_serialize(self):
+        """ Serializes the model entry according to the given lookup data
+
+        Args:
+
+        Returns:
+            serialized_data (dict)
+        """
+        entry = self.model.objects.get(**self.lookup)
+        serialized_data = self.model_to_geo_json(entry)
+        return serialized_data