Improved serialization performance between 25% and 29%

Author: nemesifier

rest_framework_gis/fields.py

@@ -6,6 +6,8 @@
 from django.utils.translation import ugettext_lazy as _
 from rest_framework.fields import Field, SerializerMethodField
 
+from .utils import OrderedDict
+
 
 __all__ = ['GeometryField', 'GeometrySerializerMethodField']
 
@@ -23,7 +25,7 @@ def __init__(self, **kwargs):
     def to_representation(self, value):
         if isinstance(value, dict) or value is None:
             return value
-        return JsonDict(GEOSGeometry(value).geojson)
+        return GeoJsonDict(value)
 
     def to_internal_value(self, value):
         if value == '' or value is None:
@@ -47,20 +49,23 @@ def validate_empty_values(self, data):
 class GeometrySerializerMethodField(SerializerMethodField):
     def to_representation(self, value):
         value = super(GeometrySerializerMethodField, self).to_representation(value)
-        return JsonDict(GEOSGeometry(value).geojson)
+        return GeoJsonDict(value)
 
 
-class JsonDict(dict):
+class GeoJsonDict(OrderedDict):
     """
-    Takes GeoDjango geojson in input and converts it _back_ to a Python object
-    Retains the geojson string for python 2,
-    see: https://github.com/djangonauts/django-rest-framework-gis/pull/60
-
-    TODO: remove this when python 2 will be deprecated
+    Used for serializing GIS values to GeoJSON values
+    TODO: remove this when support for python 2.6/2.7 will be dropped
     """
-    def __init__(self, data):
-        self._geojson_string = data
-        super(JsonDict, self).__init__(json.loads(data))
+    def __init__(self, geometry):
+        super(GeoJsonDict, self).__init__((
+            ('type', geometry.geom_type),
+            ('coordinates', geometry.coords),
+        ))
 
     def __str__(self):
-        return self._geojson_string
+        """
+        Avoid { 'type': u'Point', 'coordinates': [12, 32] } in python 2.6/2.7
+        see: https://github.com/djangonauts/django-rest-framework-gis/pull/60
+        """
+        return json.dumps(self)

rest_framework_gis/serializers.py

@@ -100,18 +100,17 @@ def to_representation(self, instance):
         Serialize objects -> primitives.
         """
         ret = OrderedDict()
-        fields = [field for field in self.fields.values() if not field.write_only]
 
         # geo structure
-        if self.Meta.id_field is not False:
-            ret["id"] = ""
         ret["type"] = "Feature"
-        ret["geometry"] = {}
         ret["properties"] = OrderedDict()
         if self.Meta.bbox_geo_field or self.Meta.auto_bbox:
             ret["bbox"] = None
 
-        for field in fields:
+        for field in self.fields.values():
+            if field.write_only:
+                continue
+
             field_name = field.field_name
             value = field.get_attribute(instance)
             value_repr = None

tests/django_restframework_gis_tests/tests.py

@@ -493,7 +493,7 @@ def test_geometry_serializer_method_field(self):
         self.assertEqual(response.status_code, 200)
         self.assertEqual(response.data['properties']['name'], 'hidden geometry')
         self.assertEqual(response.data['geometry']['type'], 'Point')
-        self.assertEqual(response.data['geometry']['coordinates'], [0.0, 0.0])
+        self.assertEqual(response.data['geometry']['coordinates'], (0.0, 0.0))
 
     def test_filterset(self):
         from rest_framework_gis.filterset import GeoFilterSet