added observation endpoint

api/endpoints/obs/historical/routes.py

+from fastapi import APIRouter, Depends
+from pydantic import BaseModel
+from typing import Optional
+from core.database import CursorFromPool
+from itertools import groupby
+from datetime import timedelta, datetime
+
+
+router = APIRouter()
+
+
+class FilterModel(BaseModel):
+    station: str
+    pollutant: str
+    fromtime:  datetime
+    totime: datetime
+
+
+@router.get("/obs/historical/", tags=["obs"])
+async def aqi(filter_model: FilterModel = Depends()):
+    with CursorFromPool() as cursor:
+
+        # Get observations
+        sql = """
+          select
+              sp.id as sampling_point_id,
+              s.name as station,
+              p.notation as pollutant,
+              u.notation as unit,
+              st_x(s.geom) as lng,
+              st_y(s.geom) as lat,
+              t.timestep,
+              o.begin_position as from_time,
+              o.end_position as to_time,
+              o.value,
+              o.verification_flag,
+              o.validation_flag
+          from
+              sampling_points sp,
+              eea_pollutants p,
+              eea_times t,
+              stations s,
+              eea_concentrations u,
+              observations o
+          where 1=1
+          and sp.id = o.sampling_point_id
+          and sp.station_id = s.id
+          and sp.pollutant = p.uri
+          and sp.concentration = u.id
+          and sp.timestep = t.id
+          and t.timestep <= 86400
+          and t.timestep > 1
+          and sp.private = false
+          and o.from_time >= %(fromTime)s
+          and o.from_time < %(toTime)s
+          and lower(s.name) = lower(%(sta)s)
+          and lower(p.notation) = lower(%(pollutant)s)
+        """
+
+        cursor.execute(sql, {"sta": filter_model.station, "pollutant": filter_model.pollutant, "fromTime": filter_model.fromtime, "toTime": filter_model.totime})
+        return cursor.fetchall()