[geo] Restrict to points only #151

Fixed the issue by adding a clean method
to the location model. This method
ensures that when the geometry is not
None, it should be an instance of a Point
Geometry else a ValidationError is raised

Fixes #151

openwisp_controller/geo/models.py

@@ -1,4 +1,7 @@
 from django.contrib.gis.db import models
+from django.contrib.gis.geos import Point
+from django.core.exceptions import ValidationError
+from django.utils.translation import ugettext_lazy as _
 from django_loci.base.models import AbstractFloorPlan, AbstractLocation, AbstractObjectLocation
 
 from openwisp_users.mixins import OrgMixin, ValidateOrgMixin
@@ -8,6 +11,11 @@ class Location(OrgMixin, AbstractLocation):
     class Meta(AbstractLocation.Meta):
         abstract = False
 
+    def clean(self):
+        if self.geometry is not None and not isinstance(self.geometry, Point):
+            raise ValidationError({'geometry': _('Only point geometry is allowed')})
+        super().clean()
+
 
 class FloorPlan(OrgMixin, AbstractFloorPlan):
     location = models.ForeignKey(Location, models.CASCADE)

openwisp_controller/geo/tests/test_models.py

@@ -1,3 +1,4 @@
+from django.contrib.gis.geos import LineString, Point, Polygon
 from django.core.exceptions import ValidationError
 from django.test import TestCase
 from django_loci.tests.base.test_models import BaseTestModels
@@ -23,3 +24,21 @@ def test_floorplan_location_validation(self):
             self.assertIn('location', e.message_dict)
         else:
             self.fail('ValidationError not raised')
+
+    def test_add_location_with_point_geometry(self):
+        self._create_location(geometry=Point(0, 0, srid=4326), name='point')
+        obj = self.location_model.objects.get(name='point')
+        self.assertEqual(obj.name, 'point')
+
+    def test_add_location_with_line_geometry(self):
+        with self.assertRaisesMessage(ValidationError, 'Only point geometry is allowed'):
+            self._create_location(geometry=LineString((0, 0), (1, 1), srid=4326), name='line')
+        obj = self.location_model.objects.filter(name='line')
+        self.assertEqual(obj.count(), 0)
+
+    def tes_add_location_with_polygon_geometry(self):
+        with self.assertRaisesMessage(ValidationError, 'Only point geometry is allowed'):
+            poly = Polygon((0, 0), (0, 1), (1, 1), (1, 0), (0, 0), srid=4326)
+            self._create_location(geometry=poly, name='poly')
+        obj = self.location_model.objects.filter(name='poly')
+        self.assertEqual(obj.count(), 0)