def decorate_queryset(
cls,
feature_type: FeatureType,
queryset: models.QuerySet,
output_crs: CRS,
**params,
):
"""Update the queryset to let the database render the GML output.
This is far more efficient then GeoDjango's logic, which performs a
C-API call for every single coordinate of a geometry.
"""
queryset = super().decorate_queryset(feature_type, queryset,
output_crs, **params)
# Retrieve geometries as pre-rendered instead.
gml_elements = feature_type.xsd_type.geometry_elements
geo_selects = get_db_geometry_selects(gml_elements, output_crs)
if geo_selects:
queryset = queryset.defer(*geo_selects.keys()).annotate(
_as_envelope_gml=cls.get_db_envelope_as_gml(
feature_type, queryset, output_crs),
**build_db_annotations(geo_selects, "_as_gml_{name}", AsGML),
)
return queryset
def decorate_queryset(
cls,
feature_type: FeatureType,
queryset: models.QuerySet,
output_crs: CRS,
**params,
) -> models.QuerySet:
queryset = super().decorate_queryset(feature_type, queryset,
output_crs, **params)
# Instead of reading the binary geometry data,
# ask the database to generate EWKT data directly.
geo_selects = get_db_geometry_selects(
feature_type.xsd_type.geometry_elements, output_crs)
if geo_selects:
queryset = queryset.defer(*geo_selects.keys()).annotate(
**build_db_annotations(geo_selects, "_as_ewkt_{name}", AsEWKT))
return queryset
def decorate_queryset(
cls,
feature_type: FeatureType,
queryset: models.QuerySet,
output_crs: CRS,
**params,
):
queryset = super().decorate_queryset(feature_type, queryset,
output_crs, **params)
# Other geometries can be excluded as these are not rendered by 'properties'
other_geometries = [
model_field.name for model_field in feature_type.geometry_fields
if model_field is not feature_type.geometry_field
]
if other_geometries:
queryset = queryset.defer(*other_geometries)
return queryset