Ticket #18654: django.contrib.gis.property_fields.patch

django/contrib/gis/tests/layermap/models.py

@@ -1 +1 @@
 from django.contrib.gis.db import models
+from django.core.exceptions import ObjectDoesNotExist
 
 class State(models.Model):
     name = models.CharField(max_length=20)
@@ -44 +45 @@
 class ICity2(ICity1):
     dt_time = models.DateTimeField(auto_now=True)
 
+class CityHistorical(models.Model) :
+    name = models.CharField(max_length=25, primary_key=True)
+    density = models.DecimalField(max_digits=7, decimal_places=1)
+    dt = models.DateField()
+    point = models.PointField()
+    objects = models.GeoManager()
+
+    @property
+    def population(self) :
+        return self.pop.order_by('-year')[0].count
+
+    @population.setter
+    def population(self, count, year=2005) :
+        try :
+            pop = self.pop.get(year=year)
+        except ObjectDoesNotExist :
+            self.pop.create(count=count, year=year)
+        else :
+            pop.count = count
+            pop.save()
+
+class Population(models.Model) :
+    city = models.ForeignKey(CityHistorical, related_name='pop')
+    count = models.IntegerField()
+    year = models.IntegerField()
+
 class Invalid(models.Model):
     point = models.PointField()
 
@@ -64 +91 @@
                 'point' : 'POINT',
                 }
 
+cityhistorical_mapping = {'name': 'Name',
+                          'density': 'Density',
+                          'dt': 'Created',
+                          'point': 'POINT',
+                          'population': 'Population',
+                         }
+
 inter_mapping = {'name' : 'Name',
                  'length' : 'Length',
                  'path' : 'LINESTRING',

django/contrib/gis/tests/layermap/tests.py

@@ -12 +12 @@
 
 from .models import (
     City, County, CountyFeat, Interstate, ICity1, ICity2, Invalid, State,
-    city_mapping, co_mapping, cofeat_mapping, inter_mapping)
+    CityHistorical, city_mapping, cityhistorical_mapping, co_mapping,
+    cofeat_mapping, inter_mapping)
 
 
 shp_path = os.path.realpath(os.path.join(os.path.dirname(__file__), os.pardir, 'data'))
@@ -281 +282 @@
         lm.save(silent=True, strict=True)
         self.assertEqual(City.objects.count(), 3)
         self.assertEqual(City.objects.all().order_by('name_txt')[0].name_txt, "Houston")
+
+    def test_property_field(self) :
+        "Tests fields implemented as properties"
+        mapping = copy(cityhistorical_mapping)
+        lm = LayerMapping(CityHistorical, city_shp, mapping)
+        lm.save(silent=True, strict=True)
+        self.assertEqual(CityHistorical.objects.count(), 3)
+        houston = CityHistorical.objects.get(name='Houston')
+        self.assertEqual(houston.population, 2144491)

django/contrib/gis/utils/layermapping.py

@@ -178 +178 @@
             try:
                 model_field = self.model._meta.get_field(field_name)
             except models.fields.FieldDoesNotExist:
+                # If the attribute is a property instance we trust that it has a setter and does the right thing(tm).
+                if isinstance(getattr(self.model, field_name, False),
+                        property) :
+                    self.fields[field_name] = field_name
+                    continue
                 raise LayerMapError('Given mapping field "%s" not in given Model fields.' % field_name)
 
             # Getting the string name for the Django field class (e.g., 'PointField').
@@ -296 +301 @@
                 # The related _model_, not a field was passed in -- indicating
                 # another mapping for the related Model.
                 val = self.verify_fk(feat, model_field, ogr_name)
+            elif isinstance(model_field, basestring) :
+                # The field is a model implemented property
+                ogr_field = feat[ogr_name]
+                if isinstance(ogr_field, OFTString) :
+                    if self.encoding :
+                        val = unicode(ogr_field.value, self.encoding)
+                    else :
+                        val = ogr_field.value
+                else :
+                    val = ogr_field.value
             else:
                 # Otherwise, verify OGR Field type.
                 val = self.verify_ogr_field(feat[ogr_name], model_field)