# Parcel fetcher improvements

* switch from custom auth header to standard 'Authorization' bearer token header
* drops definition of custom schneider authentication header from settings
* refactors ParcelFetcher geom-shrinking code into own method for better maintainability

.env.sample

@@ -31,7 +31,6 @@ GEOPORTAL_RLP_PASSWORD=CHANGE_ME
 # Schneider
 SCHNEIDER_BASE_URL=https://schneider.naturschutz.rlp.de
 SCHNEIDER_AUTH_TOKEN=CHANGE_ME
-SCHNEIDER_AUTH_HEADER=auth
 
 # SSO
 SSO_SERVER_BASE_URL=https://login.naturschutz.rlp.de

konova/sub_settings/schneider_settings.py

@@ -8,5 +8,4 @@ Created on: 14.12.22
 from konova.sub_settings.django_settings import env
 
 base_url = env("SCHNEIDER_BASE_URL")
-auth_header = env("SCHNEIDER_AUTH_HEADER")
 auth_header_token = env("SCHNEIDER_AUTH_TOKEN")

konova/utils/schneider/fetcher.py

@@ -9,16 +9,14 @@ import json
 from json import JSONDecodeError
 
 import requests
-from django.contrib.gis import gdal
+from django.contrib.gis.geos import GEOSGeometry
 
 from konova.sub_settings import schneider_settings
-from konova.sub_settings.lanis_settings import DEFAULT_SRID
 from konova.sub_settings.proxy_settings import PROXIES
 
 
 class ParcelFetcher:
     base_url = schneider_settings.base_url
-    auth_header = schneider_settings.auth_header
     auth_header_token = schneider_settings.auth_header_token
 
     geometry = None
@@ -30,30 +28,47 @@ class ParcelFetcher:
             raise AssertionError("Geometry must not be none")
         self.geometry = geometry
 
-        # Reduce size of geometry to avoid "intersections" because of exact border matching
-        buffer_threshold = 0.001
-        geom = geometry.geom.buffer(-buffer_threshold)
-        if geom.area < buffer_threshold:
-            # Fallback for malicious geometries which are way too small and would disappear on negative buffering
-            geom = geometry.geom
-        try:
-            geom.transform(DEFAULT_SRID)
-        except gdal.GDALException as e:
-            raise ValueError(f"{str(e)}\nCould not transform geometry (id: {geometry.id}) to {DEFAULT_SRID}:\n {geom.geojson}")
-        self.geojson = geom.ewkt
+        geom = self._shrink_geometry(geometry.geom)
+
+        self.geojson = geom.geojson
         self.results = []
 
-    def get_parcels(self, url: str = None):
-        post_url = url
-        if post_url is None:
-            post_url = f"{self.base_url}/parcel/intersect/"
+    def _shrink_geometry(self, geometry: GEOSGeometry) -> GEOSGeometry:
+        """ Shrink geometry by a minimal factor to avoid intersections with neighboring features due to
+        exact outline match.
+
+        Args:
+            geometry (GEOSGeometry): geometry to shrink
+
+        Returns:
+            geom (GEOSGeometry): Shrinked geometry
+        """
+        # Reduce size of geometry to avoid "intersections" because of exact border matching
+        buffer_threshold = 0.001
+        return_geom = geometry.buffer(-buffer_threshold)
+        if return_geom.area < buffer_threshold:
+            # Fallback for malicious geometries which are way too small and would disappear on negative buffering
+            return_geom = geometry
+        return return_geom
+
+    def get_parcels(self, url: str = None) -> list:
+        """ Perform parcel fetching
+
+        Args:
+            url (None|str): (optional) Provide an alternative url for fetching parcels. Default will be used if None
+
+        Returns:
+            results (list): List of fetched parcels
+        """
+        if url is None:
+            url = f"{self.base_url}/parcel/intersect/"
 
         response = requests.post(
-            url=post_url,
+            url=url,
             proxies=PROXIES,
             data=self.geojson,
             headers={
-                self.auth_header: self.auth_header_token
+                "Authorization": f"Bearer {self.auth_header_token}"
             }
         )