Added floorspace calculation rule

rabotnikobm/rules/get_floorspace.py

+#!/usr/bin/env python3
+import logging
+
+from rabotnik.storages.base import StorageBase as RabotnikStorage
+from rabotnik import Rule  # pylint: disable=import-error
+
+logger = logging.getLogger()
+
+
+class Floorspace(Rule):
+    def __init__(self, storage: RabotnikStorage):
+        """Calculate floorspace of buildings.
+
+        Args:
+            storage: Storage serving building data.
+        """
+        self.storage = storage
+
+    async def evaluate(self, payload: dict) -> tuple:
+        building_id = payload["building_id"]
+
+        async for data in self.storage.iter_results(
+            f"""
+            SELECT ST_Area(ST_Transform(geometry, 4326)) *
+                CAST(br.tags->'building:levels' AS float)
+            FROM osm_building_relations  AS br
+            UNION ALL
+            SELECT ST_Area(ST_Transform(geometry, 4326)) *
+                 CAST(bp.tags->'building:levels' AS float)
+            FROM osm_building_polygons AS bp
+            WHERE id = {building_id};
+        """
+        ):
+
+            yield data