static GeoJsonPolygon <GeoJson2DGeographicCoordinates> BuildLimitBox
(DbGetGeoFilterRequest request)
{
double yShift = (180 / Math.PI) *
(request.DistanceLat / EarthRadiusMeters);
double xShift = (180 / Math.PI) *
(request.DistanceLong / EarthRadiusMeters) /
Math.Cos(request.CenterLat);
var polygon = new GeoJsonPolygon <_2DCoord>(
new GeoJsonPolygonCoordinates <_2DCoord>(
new GeoJsonLinearRingCoordinates <_2DCoord>(
new List <_2DCoord>
{
new _2DCoord(request.CenterLong - xShift,
request.CenterLat - yShift),
new _2DCoord(request.CenterLong + xShift,
request.CenterLat - yShift),
new _2DCoord(request.CenterLong + xShift,
request.CenterLat + yShift),
new _2DCoord(request.CenterLong - xShift,
request.CenterLat + yShift),
new _2DCoord(request.CenterLong - xShift,
request.CenterLat - yShift),
})));
return(polygon);
}
public async Task <ListResponse <Geo> > Handle
(DbGetGeoFilterRequest request,
CancellationToken cancellationToken)
{
try
{
Logger.LogInformation(LogEvent.DatabaseRequest,
"Request={Request}.", request.ToDictionary());
var validation = new DbGetGeoFilterRequestValidator()
.Validate(request);
if (!validation.IsValid)
{
Logger.LogWarning
(LogEvent.DatabaseRequestArgumentError,
"Database request validation" +
" error. Error={Error}.", validation.Errors);
return(ErrorResult("Database request validation error"));
}
var db = DbContext.Db;
var query = BuildQuery(request);
var totalCount = await query
.CountAsync()
.ConfigureAwait(false);
if (totalCount == 0)
{
return(new ListResponse <Geo>(new List <Geo>(),
totalCount));
}
var pagedQuery = AddPagination(query, request);
var dbEntityList = await pagedQuery
.ToListAsync()
.ConfigureAwait(false);
if (dbEntityList is null)
{
Logger.LogWarning
(LogEvent.DatabaseEmptyResponse,
"Database Geo null response.");
return(ErrorResult("Database Geo null response."));
}
var entities = dbEntityList.Select(x => x.ToEntity <Geo>());
var result = new ListResponse <Geo>(entities, totalCount);
return(result);
}
catch (Exception e)
{
Logger.LogWarning(LogEvent.DatabaseExceptionError, e,
"Database exception error. Error={Error}.", e.Message);
return(ErrorResult("Database exception error"));
}
}
public static Dictionary <string, object> ToDictionary
(this DbGetGeoFilterRequest from)
{
if (from is null)
{
return(null);
}
return(new Dictionary <string, object>
{
{ nameof(from.Archived), from.Archived },
{ nameof(from.Contains), from.Contains },
{ nameof(from.Limit), from.Limit },
{ nameof(from.Offset), from.Offset },
{ nameof(from.DistanceLat), from.DistanceLat },
{ nameof(from.DistanceLong), from.DistanceLong },
{ nameof(from.CenterLat), from.CenterLat },
{ nameof(from.CenterLong), from.CenterLong },
{ nameof(from.ProjectId), from.ProjectId },
});
}
private IMongoQueryable <DbGeo> BuildQuery
(
DbGetGeoFilterRequest request
)
{
var query = DbContext.Db.GetCollection <DbGeo>
(Defaults.GeoCollectionName)
.AsQueryable();
if (!string.IsNullOrWhiteSpace(request.Contains))
{
query = query.WhereText(request.Contains);
}
if (request.Archived.HasValue)
{
query = query.Where(x => x.IsArchived == request.Archived);
}
if (!string.IsNullOrWhiteSpace(request.ProjectId))
{
query = query.Where(x => x.ProjectId == request.ProjectId);
}
// Add geospatial filter
if (request.DistanceLat > 0 && request.DistanceLong > 0)
{
var polygon = BuildLimitBox(request);
var filterBuilder = Builders <DbGeo> .Filter;
var filter = filterBuilder
.GeoIntersects <GeoJson2DGeographicCoordinates>
((FieldDefinition <DbGeo>) "GeoJson.features.geometry",
polygon);
query = query.Where(x => filter.Inject());
}
return(query);