maps: add custom PointSerializerMixin which allows to save geojson

points as GeoDjango to the database for better filtering capabilites and
serializes them as geojson features.

- add PointInPolygon validator which validates that a given point is in
  the provided polygon.

Author: Julian Dehm

adhocracy4/maps/serializers.py

@@ -0,0 +1,37 @@
+import json
+from collections import OrderedDict
+
+
+class PointSerializerMixin:
+    """Serializes a GeoDjango Point field into a geojson feature. Requires the field `geo_field`
+    on the Meta class of the serializer to be set to the name of the model field containing the point.
+    """
+
+    def to_internal_value(self, data):
+        if self.Meta.geo_field and self.Meta.geo_field in data:
+            geo_field = data[self.Meta.geo_field]
+            point = json.loads(geo_field)
+            data = data.copy()
+            if "geometry" in point:
+                data[self.Meta.geo_field] = json.dumps(point["geometry"])
+            properties = self.get_properties()
+            if "properties" in point:
+                for property in properties:
+                    if property in point["properties"]:
+                        data[property] = point["properties"][property]
+        return super().to_internal_value(data)
+
+    def to_representation(self, instance):
+        data = super().to_representation(instance)
+        if self.Meta.geo_field and self.Meta.geo_field in data:
+            feature = OrderedDict()
+            feature["type"] = "Feature"
+            feature["geometry"] = data[self.Meta.geo_field]
+            props = OrderedDict()
+            properties = self.get_properties()
+            for property in properties:
+                if hasattr(instance, property):
+                    props[property] = getattr(instance, property)
+            feature["properties"] = props
+            data[self.Meta.geo_field] = feature
+        return data

adhocracy4/maps/validators.py

@@ -0,0 +1,29 @@
+from django.contrib.gis.geos import Polygon
+from django.core.exceptions import ValidationError
+from django.utils.deconstruct import deconstructible
+from django.utils.translation import gettext_lazy as _
+
+
+@deconstructible
+class PointInPolygonValidator:
+    """Validate that the given point is within the polygon, otherwise raise ValidationError."""
+
+    polygon: Polygon = None
+    message = _("Point is not inside the specified area")
+    code = "invalid"
+
+    def __init__(self, polygon):
+        self.polygon = polygon
+
+    def __call__(self, value):
+        """"""
+        if not self.polygon.contains(value):
+            raise ValidationError(message=self.message, code=self.code)
+
+    def __eq__(self, other):
+        return (
+            isinstance(other, PointInPolygonValidator)
+            and self.message == other.message
+            and self.code == other.code
+            and self.polygon == other.polygon
+        )

adhocracy4/projects/migrations/0048_project_geos_point_project_house_number_and_more.py

@@ -0,0 +1,40 @@
+# Generated by Django 4.2.17 on 2025-01-28 14:21
+
+import django.contrib.gis.db.models.fields
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("a4projects", "0047_alter_project_image_alter_project_tile_image"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="project",
+            name="geos_point",
+            field=django.contrib.gis.db.models.fields.PointField(
+                blank=True,
+                help_text="Locate your project. Click inside the marked area or type in an address to set the marker. A set marker can be dragged when pressed.",
+                null=True,
+                srid=4326,
+                verbose_name="Can your project be located on the map?",
+            ),
+        ),
+        migrations.AddField(
+            model_name="project",
+            name="house_number",
+            field=models.CharField(blank=True, max_length=10, null=True),
+        ),
+        migrations.AddField(
+            model_name="project",
+            name="streetname",
+            field=models.CharField(blank=True, max_length=200, null=True),
+        ),
+        migrations.AddField(
+            model_name="project",
+            name="zip_code",
+            field=models.CharField(blank=True, max_length=20, null=True),
+        ),
+    ]

adhocracy4/projects/migrations/0049_project_geos_point.py

@@ -0,0 +1,77 @@
+# Generated by Django 4.2.17 on 2025-01-27 15:11
+
+import json
+import logging
+import django.contrib.gis.db.models.fields
+
+from django.contrib.gis.geos import GEOSGeometry
+from django.contrib.gis.geos import Point
+from django.db import migrations, models
+
+logger = logging.getLogger(__name__)
+
+
+def migrate_project_point_field(apps, schema_editor):
+    project = apps.get_model("a4projects", "Project")
+    for project in project.objects.all():
+        geojson_point = project.point
+        if not "geometry" in geojson_point:
+            logger.warning(
+                "error migrating point of project "
+                + project.name
+                + ": "
+                + str(geojson_point)
+            )
+            continue
+        project.geos_point = GEOSGeometry(json.dumps(geojson_point["geometry"]))
+        if "properties" in geojson_point:
+            properties = geojson_point["properties"]
+            if "strname" in properties:
+                project.street_name = properties["strname"]
+            if "hsnr" in properties:
+                project.house_number = properties["hsnr"]
+            if "plz" in properties:
+                project.zip_code = properties["plz"]
+        project.save()
+
+
+def migrate_project_geos_point_field(apps, schema_editor):
+    project = apps.get_model("a4projects", "Project")
+    for project in project.objects.all():
+        project.point = project.geos_point
+        project.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("a4projects", "0048_project_geos_point_project_house_number_and_more"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            migrate_project_point_field, reverse_code=migrations.RunPython.noop
+        ),
+        migrations.RemoveField(
+            model_name="project",
+            name="point",
+        ),
+        migrations.AddField(
+            model_name="project",
+            name="point",
+            field=django.contrib.gis.db.models.fields.PointField(
+                blank=True,
+                help_text="Locate your project. Click inside the marked area or type in an address to set the marker. A set marker can be dragged when pressed.",
+                null=True,
+                srid=4326,
+                verbose_name="Can your project be located on the map?",
+            ),
+        ),
+        migrations.RunPython(
+            migrate_project_geos_point_field, reverse_code=migrations.RunPython.noop
+        ),
+        migrations.RemoveField(
+            model_name="project",
+            name="geos_point",
+        ),
+    ]

adhocracy4/projects/models.py

@@ -3,6 +3,7 @@
 from autoslug import AutoSlugField
 from django.conf import settings
 from django.contrib.auth.models import Group
+from django.contrib.gis.db import models as gis_models
 from django.core.validators import RegexValidator
 from django.db import models
 from django.urls import reverse
@@ -17,7 +18,6 @@
 from adhocracy4.administrative_districts.models import AdministrativeDistrict
 from adhocracy4.images import fields
 from adhocracy4.images.validators import ImageAltTextValidator
-from adhocracy4.maps.fields import PointField
 from adhocracy4.models import base
 
 from .enums import Access
@@ -87,7 +87,7 @@ class ProjectLocationMixin(models.Model):
     class Meta:
         abstract = True
 
-    point = PointField(
+    point = gis_models.PointField(
         null=True,
         blank=True,
         verbose_name=_("Can your project be located on the map?"),
@@ -99,6 +99,10 @@ class Meta:
         ),
     )
 
+    streetname = models.CharField(null=True, blank=True, max_length=200)
+    house_number = models.CharField(null=True, blank=True, max_length=10)
+    zip_code = models.CharField(null=True, blank=True, max_length=20)
+
     administrative_district = models.ForeignKey(
         AdministrativeDistrict,
         on_delete=models.CASCADE,

changelog/8472.md

@@ -0,0 +1,8 @@
+### Added
+
+- add new `PointSerializerMixin` which enables a serializer to correctly save geojson features as GeoDjango
+in the database and serialize it back as geojson feature.
+
+### Changed
+
+- use spatialite as database to support GeoDjango

requirements/base.txt

@@ -8,6 +8,7 @@ django-enumfield==3.1
 django-filter==24.3
 django-widget-tweaks==1.5.0
 djangorestframework==3.15.2
+djangorestframework-gis==1.1.0
 easy-thumbnails[svg]==2.10
 html5lib==1.1
 jsonfield==3.1.0

tests/maps/test_map_validators.py

@@ -0,0 +1,44 @@
+import json
+
+import pytest
+from django.conf import settings
+from django.contrib.gis.geos import GEOSGeometry
+from django.forms import ValidationError
+
+from adhocracy4.maps.validators import PointInPolygonValidator
+
+
+@pytest.mark.django_db
+def test_point_in_polygon_validator_valid_point():
+    polygon = GEOSGeometry(
+        json.dumps(settings.BERLIN_POLYGON["features"][0]["geometry"])
+    )
+    validator = PointInPolygonValidator(polygon=polygon)
+
+    # point within the berlin polygon
+    geojson_point = {
+        "type": "Feature",
+        "geometry": {
+            "type": "Point",
+            "coordinates": [13.411924777644563, 52.499598134440944],
+        },
+    }
+    point = GEOSGeometry(json.dumps(geojson_point["geometry"]))
+    validator(point)
+
+
+@pytest.mark.django_db
+def test_point_in_polygon_validator_invalid_point():
+    polygon = GEOSGeometry(
+        json.dumps(settings.BERLIN_POLYGON["features"][0]["geometry"])
+    )
+    validator = PointInPolygonValidator(polygon=polygon)
+
+    # point outside the berlin polygon
+    geojson_point = {
+        "type": "Feature",
+        "geometry": {"type": "Point", "coordinates": [13.459894, 51.574425]},
+    }
+    point = GEOSGeometry(json.dumps(geojson_point["geometry"]))
+    with pytest.raises(ValidationError):
+        validator(point)