speedup geometry serialization by smart wrapping magic

This commit is contained in:
Laura Klünder 2018-12-22 22:27:19 +01:00
parent 4819d67f99
commit f1e379aea8
3 changed files with 54 additions and 9 deletions

View file

@ -14,7 +14,7 @@ from shapely import validation
from shapely.geometry import LineString, MultiPolygon, Point, Polygon, mapping, shape
from shapely.geometry.base import BaseGeometry
from c3nav.mapdata.utils.geometry import clean_geometry
from c3nav.mapdata.utils.geometry import WrappedGeometry, clean_geometry
from c3nav.mapdata.utils.json import format_geojson
logger = logging.getLogger('c3nav')
@ -52,7 +52,7 @@ class GeometryField(models.TextField):
def from_db_value(self, value, expression, connection):
if value is None:
return value
return shape(json.loads(value))
return WrappedGeometry(json.loads(value))
def to_python(self, value):
if value is None or value == '':

View file

@ -4,11 +4,11 @@ from collections import OrderedDict
from django.db import models
from django.utils.functional import cached_property
from django.utils.translation import ugettext_lazy as _
from shapely.geometry import Point, box, mapping
from shapely.geometry import Point, box
from shapely.ops import unary_union
from c3nav.mapdata.models.base import SerializableMixin
from c3nav.mapdata.utils.geometry import assert_multipolygon, good_representative_point
from c3nav.mapdata.utils.geometry import assert_multipolygon, good_representative_point, smart_mapping
from c3nav.mapdata.utils.json import format_geojson
geometry_affecting_fields = ('height', 'width', 'access_restriction')
@ -45,11 +45,11 @@ class GeometryMixin(SerializableMixin):
result = OrderedDict((
('type', 'Feature'),
('properties', self.get_geojson_properties(instance=instance)),
('geometry', format_geojson(mapping(self.geometry), round=False)),
('geometry', format_geojson(smart_mapping(self.geometry), round=False)),
))
original_geometry = getattr(self, 'original_geometry', None)
if original_geometry:
result['original_geometry'] = format_geojson(mapping(original_geometry), round=False)
result['original_geometry'] = format_geojson(smart_mapping(original_geometry), round=False)
return result
@classmethod
@ -72,7 +72,7 @@ class GeometryMixin(SerializableMixin):
def _serialize(self, geometry=True, simple_geometry=False, **kwargs):
result = super()._serialize(simple_geometry=simple_geometry, **kwargs)
if geometry:
result['geometry'] = format_geojson(mapping(self.geometry), round=False)
result['geometry'] = format_geojson(smart_mapping(self.geometry), round=False)
if simple_geometry:
result['point'] = (self.level_id, ) + tuple(round(i, 2) for i in self.point.coords[0])
if not isinstance(self.geometry, Point):
@ -84,9 +84,9 @@ class GeometryMixin(SerializableMixin):
def details_display(self, detailed_geometry=True, **kwargs):
result = super().details_display(**kwargs)
if detailed_geometry:
result['geometry'] = format_geojson(mapping(self.geometry), round=False)
result['geometry'] = format_geojson(smart_mapping(self.geometry), round=False)
else:
result['geometry'] = format_geojson(mapping(box(*self.geometry.bounds)), round=False)
result['geometry'] = format_geojson(smart_mapping(box(*self.geometry.bounds)), round=False)
return result
def get_shadow_geojson(self):

View file

@ -6,10 +6,13 @@ from typing import List, Sequence, Union
import matplotlib.pyplot as plt
from django.core import checks
from django.utils.functional import cached_property
from matplotlib.patches import PathPatch
from matplotlib.path import Path
from shapely import prepared, speedups
from shapely.geometry import GeometryCollection, LinearRing, LineString, MultiLineString, MultiPolygon, Point, Polygon
from shapely.geometry import mapping as shapely_mapping
from shapely.geometry import shape as shapely_shape
if speedups.available:
speedups.enable()
@ -29,6 +32,48 @@ def check_speedups(app_configs, **kwargs):
return errors
class WrappedGeometry():
picklable = False
wrapped_geojson = None
def __init__(self, geojson):
self.wrapped_geojson = geojson
@cached_property
def wrapped_geom(self):
return shapely_shape(self.wrapped_geojson)
def __getattr__(self, name):
if name in ('__getstate__'):
self.picklable = True
# make sure geometry is cached
if self.wrapped_geojson:
# noinspection PyStatementEffect
self.wrapped_geom
raise AttributeError
if name in ('__reduce__', '__getstate__', '__setstate__', '__reduce_ex__',
'__getnewargs__', '__getnewargs_ex__'):
raise AttributeError
return getattr(self.wrapped_geom, name)
@property
def __class__(self):
result = WrappedGeometry if self.picklable else self.wrapped_geom.__class__
self.__dict__.pop('picklable', None)
return result
def unwrap_geometry(geometry):
return getattr(geometry, 'geom', geometry)
def smart_mapping(geometry):
if hasattr(geometry, 'wrapped_geojson'):
print('being smart!')
return geometry.wrapped_geojson
return shapely_mapping(geometry)
def clean_geometry(geometry):
"""
if the given geometry is a Polygon and invalid, try to make it valid if it results in a Polygon (not MultiPolygon)