public static async Task <ElevationLocation> FindOrUpdateInDatabase(ElevationConfigContext db, ulong c, IElevationService service)
{
var cellId = new S2CellId(c);
var latlng = cellId.ToLatLng();
return(await FindOrUpdateInDatabase(db, latlng.LatDegrees, latlng.LngDegrees, service).ConfigureAwait(false));
}
public static async Task <ElevationLocation> FindOrUpdateInDatabase(ElevationConfigContext db, double latitude, double longitude, IElevationService service)
{
latitude = Math.Round(latitude, GEOLOCATION_PRECISION);
longitude = Math.Round(longitude, GEOLOCATION_PRECISION);
var elevationLocation = db.ElevationLocation.FirstOrDefault(x => x.Latitude == latitude && x.Longitude == longitude);
if (elevationLocation != null)
{
return(elevationLocation);
}
for (var i = 0; i < MAX_RETRIES; i++)
{
try
{
var altitude = await service.GetElevation(latitude, longitude).ConfigureAwait(false);
if (altitude == 0 || altitude < -100)
{
// Invalid altitude
return(null);
}
db.ElevationLocation.Add(new ElevationLocation(latitude, longitude)
{
Altitude = altitude
});
await db.SaveChangesAsync().ConfigureAwait(false);
return(elevationLocation);
}
catch (Exception)
{
// Just ignore exception and retry after delay
await Task.Delay(i * 100).ConfigureAwait(false);
}
}
return(null);
}