Fixed #25141 -- Diminished GDAL dependence during geojson serialization

Only require GDAL if contained geometries need coordinate transformations.
Thanks drepo for the report and Tim Graham for the review.
This commit is contained in:
Claude Paroz 2015-07-18 14:50:08 +02:00
parent 774c16d16e
commit 1da170a203
5 changed files with 47 additions and 16 deletions

View File

@ -2,6 +2,7 @@
This module houses the Geometry Collection objects:
GeometryCollection, MultiPoint, MultiLineString, and MultiPolygon
"""
import json
from ctypes import byref, c_int, c_uint
from django.contrib.gis.geos import prototypes as capi
@ -83,6 +84,19 @@ class GeometryCollection(GEOSGeometry):
_set_single = GEOSGeometry._set_single_rebuild
_assign_extended_slice = GEOSGeometry._assign_extended_slice_rebuild
@property
def json(self):
if self.__class__.__name__ == 'GeometryCollection':
return json.dumps({
'type': self.__class__.__name__,
'geometries': [
{'type': geom.__class__.__name__, 'coordinates': geom.coords}
for geom in self
],
})
return super(GeometryCollection, self).json
geojson = json
@property
def kml(self):
"Returns the KML for this Geometry Collection."

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@ -4,6 +4,7 @@
"""
from __future__ import unicode_literals
import json
from ctypes import addressof, byref, c_double
from django.contrib.gis import gdal
@ -411,12 +412,9 @@ class GEOSGeometry(GEOSBase, ListMixin):
@property
def json(self):
"""
Returns GeoJSON representation of this Geometry if GDAL is installed.
Returns GeoJSON representation of this Geometry.
"""
if gdal.HAS_GDAL:
return self.ogr.json
else:
raise GEOSException('GeoJSON output only supported when GDAL is installed.')
return json.dumps({'type': self.__class__.__name__, 'coordinates': self.coords})
geojson = json
@property

View File

@ -17,17 +17,14 @@ class Serializer(JSONSerializer):
def _init_options(self):
super(Serializer, self)._init_options()
self.geometry_field = self.json_kwargs.pop('geometry_field', None)
self.srs = SpatialReference(self.json_kwargs.pop('srid', 4326))
self.srid = self.json_kwargs.pop('srid', 4326)
def start_serialization(self):
if not HAS_GDAL:
# GDAL is needed for the geometry.geojson call
raise SerializationError("The geojson serializer requires the GDAL library.")
self._init_options()
self._cts = {} # cache of CoordTransform's
self.stream.write(
'{"type": "FeatureCollection", "crs": {"type": "name", "properties": {"name": "EPSG:%d"}},'
' "features": [' % self.srs.srid)
' "features": [' % self.srid)
def end_serialization(self):
self.stream.write(']}')
@ -48,10 +45,15 @@ class Serializer(JSONSerializer):
"properties": self._current,
}
if self._geometry:
if self._geometry.srid != self.srs.srid:
if self._geometry.srid != self.srid:
# If needed, transform the geometry in the srid of the global geojson srid
if not HAS_GDAL:
raise SerializationError(
'Unable to convert geometry to SRID %s when GDAL is not installed.' % self.srid
)
if self._geometry.srid not in self._cts:
self._cts[self._geometry.srid] = CoordTransform(self._geometry.srs, self.srs)
srs = SpatialReference(self.srid)
self._cts[self._geometry.srid] = CoordTransform(self._geometry.srs, srs)
self._geometry.transform(self._cts[self._geometry.srid])
data["geometry"] = eval(self._geometry.geojson)
else:

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@ -7,9 +7,17 @@ GeoJSON Serializer
.. module:: django.contrib.gis.serializers.geojson
:synopsis: Serialization of GeoDjango models in the GeoJSON format.
GeoDjango provides a specific serializer for the `GeoJSON`__ format. The GDAL
library is required for this serializer. See :doc:`/topics/serialization` for
more information on serialization.
GeoDjango provides a specific serializer for the `GeoJSON`__ format. See
:doc:`/topics/serialization` for more information on serialization.
The GDAL library is required if any of the serialized geometries need
coordinate transformations (that is if the geometry's spatial reference system
differs from the ``srid`` serializer option).
.. versionchanged:: 1.9
The GeoJSON serializer no longer needs GDAL if all geometries are in the
same coordinate system as the ``srid`` serializer option.
__ http://geojson.org/

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@ -4,7 +4,8 @@ import json
from django.contrib.gis.geos import LinearRing, Point, Polygon
from django.core import serializers
from django.test import TestCase, skipUnlessDBFeature
from django.test import TestCase, mock, skipUnlessDBFeature
from django.utils import six
from .models import City, MultiFields, PennsylvaniaCity
@ -70,6 +71,14 @@ class GeoJSONSerializerTests(TestCase):
[int(c) for c in geodata['features'][0]['geometry']['coordinates']],
[1564802, 5613214])
@mock.patch('django.contrib.gis.serializers.geojson.HAS_GDAL', False)
def test_without_gdal(self):
# Without coordinate transformation, the serialization should succeed:
serializers.serialize('geojson', City.objects.all())
with six.assertRaisesRegex(self, serializers.base.SerializationError, '.*GDAL is not installed'):
# Coordinate transformations need GDAL
serializers.serialize('geojson', City.objects.all(), srid=2847)
def test_deserialization_exception(self):
"""
GeoJSON cannot be deserialized.