Refactor geo_interface to use standard mixin. Fixes developmentseed#96.

geojson_pydantic/features.py

@@ -5,14 +5,15 @@
 from pydantic import BaseModel, Field, validator
 from pydantic.generics import GenericModel
 
+from geojson_pydantic.geo_interface import GeoInterfaceMixin
 from geojson_pydantic.geometries import Geometry, GeometryCollection
 from geojson_pydantic.types import BBox
 
 Props = TypeVar("Props", bound=Union[Dict[str, Any], BaseModel])
 Geom = TypeVar("Geom", bound=Union[Geometry, GeometryCollection])
 
 
-class Feature(GenericModel, Generic[Geom, Props]):
+class Feature(GenericModel, Generic[Geom, Props], GeoInterfaceMixin):
     """Feature Model"""
 
     type: Literal["Feature"]
@@ -34,30 +35,8 @@ def set_geometry(cls, geometry: Any) -> Any:
 
         return geometry
 
-    @property
-    def __geo_interface__(self) -> Dict[str, Any]:
-        """GeoJSON-like protocol for geo-spatial (GIS) vector data.
 
-        ref: https://gist.github.com/sgillies/2217756#__geo_interface
-        """
-        geo: Dict[str, Any] = {
-            "type": self.type,
-            "geometry": self.geometry.__geo_interface__
-            if self.geometry is not None
-            else None,
-            "properties": self.properties,
-        }
-
-        if self.bbox:
-            geo["bbox"] = self.bbox
-
-        if self.id:
-            geo["id"] = self.id
-
-        return geo
-
-
-class FeatureCollection(GenericModel, Generic[Geom, Props]):
+class FeatureCollection(GenericModel, Generic[Geom, Props], GeoInterfaceMixin):
     """FeatureCollection Model"""
 
     type: Literal["FeatureCollection"]
@@ -75,19 +54,3 @@ def __len__(self) -> int:
     def __getitem__(self, index: int) -> Feature:
         """get feature at a given index"""
         return self.features[index]
-
-    @property
-    def __geo_interface__(self) -> Dict[str, Any]:
-        """GeoJSON-like protocol for geo-spatial (GIS) vector data.
-
-        ref: https://gist.github.com/sgillies/2217756#__geo_interface
-        """
-        features: List[Dict[str, Any]] = []
-        for feat in self.features:
-            features.append(feat.__geo_interface__)
-
-        geo: Dict[str, Any] = {"type": self.type, "features": features}
-        if self.bbox:
-            geo["bbox"] = self.bbox
-
-        return geo

geojson_pydantic/geo_interface.py

@@ -0,0 +1,23 @@
+"""Mixin for __geo_interface__ on GeoJSON objects."""
+
+from typing import Any, Dict, Protocol
+
+
+class DictProtocol(Protocol):
+    """Protocol for use as the type of self in the mixin."""
+
+    def dict(self, *, exclude_unset: bool, **args: Any) -> Dict[str, Any]:
+        """Define a dict function so the mixin knows it exists."""
+        ...
+
+
+class GeoInterfaceMixin:
+    """Mixin for __geo_interface__ on GeoJSON objects."""
+
+    @property
+    def __geo_interface__(self: DictProtocol) -> Dict[str, Any]:
+        """GeoJSON-like protocol for geo-spatial (GIS) vector data.
+
+        ref: https://gist.github.com/sgillies/2217756#__geo_interface
+        """
+        return self.dict(exclude_unset=True)

geojson_pydantic/geometries.py

@@ -1,11 +1,12 @@
 """pydantic models for GeoJSON Geometry objects."""
 
 import abc
-from typing import Any, Dict, Iterator, List, Literal, Union
+from typing import Any, Iterator, List, Literal, Union
 
 from pydantic import BaseModel, ValidationError, validator
 from pydantic.error_wrappers import ErrorWrapper
 
+from geojson_pydantic.geo_interface import GeoInterfaceMixin
 from geojson_pydantic.types import (
     LinearRing,
     LineStringCoords,
@@ -32,20 +33,12 @@ def _lines_wtk_coordinates(lines: List[List[Position]]) -> str:
     return ", ".join(f"({_position_list_wkt_coordinates(line)})" for line in lines)
 
 
-class _GeometryBase(BaseModel, abc.ABC):
+class _GeometryBase(BaseModel, abc.ABC, GeoInterfaceMixin):
     """Base class for geometry models"""
 
     type: str
     coordinates: Any
 
-    @property
-    def __geo_interface__(self) -> Dict[str, Any]:
-        """GeoJSON-like protocol for geo-spatial (GIS) vector data.
-
-        ref: https://gist.github.com/sgillies/2217756#__geo_interface
-        """
-        return {"type": self.type, "coordinates": self.coordinates}
-
     @property
     @abc.abstractmethod
     def _wkt_coordinates(self) -> str:
@@ -211,7 +204,7 @@ def _wkt_coordinates(self) -> str:
 Geometry = Union[Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon]
 
 
-class GeometryCollection(BaseModel):
+class GeometryCollection(BaseModel, GeoInterfaceMixin):
     """GeometryCollection Model"""
 
     type: Literal["GeometryCollection"]
@@ -244,18 +237,6 @@ def wkt(self) -> str:
         """Return the Well Known Text representation."""
         return f"{self._wkt_type} ({self._wkt_coordinates})"
 
-    @property
-    def __geo_interface__(self) -> Dict[str, Any]:
-        """GeoJSON-like protocol for geo-spatial (GIS) vector data.
-
-        ref: https://gist.github.com/sgillies/2217756#__geo_interface
-        """
-        geometries: List[Dict[str, Any]] = []
-        for geom in self.geometries:
-            geometries.append(geom.__geo_interface__)
-
-        return {"type": self.type, "geometries": self.geometries}
-
 
 def parse_geometry_obj(obj: Any) -> Geometry:
     """