#31 API basic implementation Token Authentication

* adds token checking to AbstractModelAPIView
* adds user accessibility filtering for intervention API v1
* extends fetch_and_serialize() method to take a dict for db filtering instead of a single field and value
* organizes urlnames into supporting formats like "api:v1:intervention"

api/models/token.py

@@ -1,4 +1,6 @@
+from django.core.exceptions import ObjectDoesNotExist
 from django.db import models
+from django.utils import timezone
 
 from konova.utils.generators import generate_token
 
@@ -21,3 +23,26 @@ class APIUserToken(models.Model):
 
     def __str__(self):
         return self.token
+
+    @staticmethod
+    def get_user_from_token(token: str):
+        """ Getter for the related user object
+
+        Args:
+            token (str): The used token
+
+        Returns:
+            user (User): Otherwise None
+        """
+        _today = timezone.now().date()
+        try:
+            token_obj = APIUserToken.objects.get(
+                token=token,
+            )
+            if not token_obj.is_active:
+                raise PermissionError("Token unverified")
+            if token_obj.valid_until is not None and token_obj.valid_until < _today:
+                raise PermissionError("Token validity expired")
+        except ObjectDoesNotExist:
+            raise PermissionError("Token invalid")
+        return token_obj.user