Added MySQL support to GIS functions

django/contrib/gis/db/backends/mysql/features.py

@@ -6,6 +6,8 @@ from django.db.backends.mysql.features import \
 class DatabaseFeatures(BaseSpatialFeatures, MySQLDatabaseFeatures):
     has_spatialrefsys_table = False
     supports_add_srs_entry = False
+    supports_distance_geodetic = False
+    supports_length_geodetic = False
     supports_distances_lookups = False
     supports_transform = False
     supports_real_shape_operations = False

django/contrib/gis/db/backends/mysql/operations.py

@@ -4,6 +4,7 @@ from django.contrib.gis.db.backends.base.operations import \
 from django.contrib.gis.db.backends.utils import SpatialOperator
 from django.contrib.gis.db.models import aggregates
 from django.db.backends.mysql.operations import DatabaseOperations
+from django.utils.functional import cached_property
 
 
 class MySQLOperations(BaseSpatialOperations, DatabaseOperations):
@@ -32,7 +33,28 @@ class MySQLOperations(BaseSpatialOperations, DatabaseOperations):
         'within': SpatialOperator(func='MBRWithin'),
     }
 
-    disallowed_aggregates = (aggregates.Collect, aggregates.Extent, aggregates.Extent3D, aggregates.MakeLine, aggregates.Union)
+    function_names = {
+        'Distance': 'ST_Distance',
+        'Length': 'GLength',
+        'Union': 'ST_Union',
+    }
+
+    disallowed_aggregates = (
+        aggregates.Collect, aggregates.Extent, aggregates.Extent3D,
+        aggregates.MakeLine, aggregates.Union,
+    )
+
+    @cached_property
+    def unsupported_functions(self):
+        unsupported = {
+            'AsGeoJSON', 'AsGML', 'AsKML', 'AsSVG', 'BoundingCircle',
+            'Difference', 'ForceRHR', 'GeoHash', 'Intersection', 'MemSize',
+            'Perimeter', 'PointOnSurface', 'Reverse', 'Scale', 'SnapToGrid',
+            'SymDifference', 'Transform', 'Translate',
+        }
+        if self.connection.mysql_version < (5, 6, 1):
+            unsupported.update({'Distance', 'Union'})
+        return unsupported
 
     def geo_db_type(self, f):
         return f.geom_type

django/contrib/gis/db/models/fields.py

@@ -169,7 +169,10 @@ class GeometryField(GeoSelectFormatMixin, Field):
         Returns true if this field's SRID corresponds with a coordinate
         system that uses non-projected units (e.g., latitude/longitude).
         """
-        return self.units_name(connection).lower() in self.geodetic_units
+        units_name = self.units_name(connection)
+        # Some backends like MySQL cannot determine units name. In that case,
+        # test if srid is 4326 (WGS84), even if this is over-simplification.
+        return units_name.lower() in self.geodetic_units if units_name else self.srid == 4326
 
     def get_distance(self, value, lookup_type, connection):
         """

django/contrib/gis/db/models/functions.py

@@ -79,6 +79,9 @@ class GeomValue(Value):
             self.value = connection.ops.Adapter(self.value)
         return super(GeomValue, self).as_sql(compiler, connection)
 
+    def as_mysql(self, compiler, connection):
+        return 'GeomFromText(%%s, %s)' % self.srid, [connection.ops.Adapter(self.value)]
+
     def as_sqlite(self, compiler, connection):
         return 'GeomFromText(%%s, %s)' % self.srid, [connection.ops.Adapter(self.value)]
 
@@ -119,8 +122,12 @@ class Area(GeoFunc):
                 self.output_field = AreaField('sq_m')
             elif not self.output_field.geodetic(connection):
                 # Getting the area units of the geographic field.
+                units = self.output_field.units_name(connection)
+                if units:
                     self.output_field = AreaField(
                         AreaMeasure.unit_attname(self.output_field.units_name(connection)))
+                else:
+                    self.output_field = FloatField()
             else:
                 # TODO: Do we want to support raw number areas for geodetic fields?
                 raise NotImplementedError('Area on geodetic coordinate systems not supported.')
@@ -198,8 +205,14 @@ class DistanceResultMixin(object):
         if geo_field.geodetic(connection):
             dist_att = 'm'
         else:
-            dist_att = DistanceMeasure.unit_attname(geo_field.units_name(connection))
+            units = geo_field.units_name(connection)
+            if units:
+                dist_att = DistanceMeasure.unit_attname(units)
+            else:
+                dist_att = None
+        if dist_att:
             return DistanceMeasure(**{dist_att: value})
+        return value
 
 
 class Distance(DistanceResultMixin, GeoFuncWithGeoParam):
@@ -263,6 +276,12 @@ class Length(DistanceResultMixin, GeoFunc):
         self.spheroid = spheroid
         super(Length, self).__init__(expr1, **extra)
 
+    def as_sql(self, compiler, connection):
+        geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info
+        if geo_field.geodetic(connection) and not connection.features.supports_length_geodetic:
+            raise NotImplementedError("This backend doesn't support Length on geodetic fields")
+        return super(Length, self).as_sql(compiler, connection)
+
     def as_postgresql(self, compiler, connection):
         geo_field = GeometryField(srid=self.srid)  # Fake field to get SRID info
         src_field = self.get_source_fields()[0]

tests/gis_tests/distapp/tests.py

@@ -438,7 +438,8 @@ class DistanceFunctionsTests(TestCase):
         # Tolerance has to be lower for Oracle
         tol = 2
         for i, z in enumerate(SouthTexasZipcode.objects.annotate(area=Area('poly')).order_by('name')):
-            self.assertAlmostEqual(area_sq_m[i], z.area.sq_m, tol)
+            # MySQL is returning a raw float value
+            self.assertAlmostEqual(area_sq_m[i], z.area.sq_m if hasattr(z.area, 'sq_m') else z.area, tol)
 
     @skipUnlessDBFeature("has_Distance_function")
     def test_distance_simple(self):
@@ -624,12 +625,12 @@ class DistanceFunctionsTests(TestCase):
             # TODO: test with spheroid argument (True and False)
         else:
             # Does not support geodetic coordinate systems.
-            with self.assertRaises(ValueError):
+            with self.assertRaises(NotImplementedError):
-                Interstate.objects.annotate(length=Length('path'))
+                list(Interstate.objects.annotate(length=Length('path')))
 
         # Now doing length on a projected coordinate system.
         i10 = SouthTexasInterstate.objects.annotate(length=Length('path')).get(name='I-10')
-        self.assertAlmostEqual(len_m2, i10.length.m, 2)
+        self.assertAlmostEqual(len_m2, i10.length.m if isinstance(i10.length, D) else i10.length, 2)
         self.assertTrue(
             SouthTexasInterstate.objects.annotate(length=Length('path')).filter(length__gt=4000).exists()
         )
@@ -652,7 +653,7 @@ class DistanceFunctionsTests(TestCase):
         for city in qs:
             self.assertEqual(0, city.perim.m)
 
-    @skipUnlessDBFeature("has_Area_function", "has_Distance_function")
+    @skipUnlessDBFeature("supports_null_geometries", "has_Area_function", "has_Distance_function")
     def test_measurement_null_fields(self):
         """
         Test the measurement functions on fields with NULL values.

tests/gis_tests/geoapp/test_functions.py

@@ -9,7 +9,7 @@ from django.db import connection
 from django.test import TestCase, skipUnlessDBFeature
 from django.utils import six
 
-from ..utils import oracle, postgis, spatialite
+from ..utils import mysql, oracle, postgis, spatialite
 
 if HAS_GEOS:
     from django.contrib.gis.geos import LineString, Point, Polygon, fromstr
@@ -165,8 +165,8 @@ class GISFunctionsTests(TestCase):
     @skipUnlessDBFeature("has_Centroid_function")
     def test_centroid(self):
         qs = State.objects.exclude(poly__isnull=True).annotate(centroid=functions.Centroid('poly'))
+        tol = 1.8 if mysql else (0.1 if oracle else 0.00001)
         for state in qs:
-            tol = 0.1  # High tolerance due to oracle
             self.assertTrue(state.poly.centroid.equals_exact(state.centroid, tol))
 
     @skipUnlessDBFeature("has_Difference_function")
@@ -248,9 +248,9 @@ class GISFunctionsTests(TestCase):
         qs = City.objects.filter(point__isnull=False).annotate(num_geom=functions.NumGeometries('point'))
         for city in qs:
             # Oracle and PostGIS 2.0+ will return 1 for the number of
-            # geometries on non-collections, whereas PostGIS < 2.0.0
+            # geometries on non-collections, whereas PostGIS < 2.0.0 and MySQL
             # will return None.
-            if postgis and connection.ops.spatial_version < (2, 0, 0):
+            if (postgis and connection.ops.spatial_version < (2, 0, 0)) or mysql:
                 self.assertIsNone(city.num_geom)
             else:
                 self.assertEqual(1, city.num_geom)
@@ -261,8 +261,8 @@ class GISFunctionsTests(TestCase):
         Track.objects.create(name='Foo', line=LineString(coords))
         qs = Track.objects.annotate(num_points=functions.NumPoints('line'))
         self.assertEqual(qs.first().num_points, 2)
-        if spatialite:
+        if spatialite or mysql:
-            # Spatialite can only count points on LineStrings
+            # Spatialite and MySQL can only count points on LineStrings
             return
 
         for c in Country.objects.annotate(num_points=functions.NumPoints('mpoly')):
@@ -455,5 +455,7 @@ class GISFunctionsTests(TestCase):
         geom = Point(-95.363151, 29.763374, srid=4326)
         ptown = City.objects.annotate(union=functions.Union('point', geom)).get(name='Dallas')
         tol = 0.00001
-        expected = fromstr('MULTIPOINT(-96.801611 32.782057,-95.363151 29.763374)', srid=4326)
+        # Undefined ordering
-        self.assertTrue(expected.equals_exact(ptown.union, tol))
+        expected1 = fromstr('MULTIPOINT(-96.801611 32.782057,-95.363151 29.763374)', srid=4326)
+        expected2 = fromstr('MULTIPOINT(-95.363151 29.763374,-96.801611 32.782057)', srid=4326)
+        self.assertTrue(expected1.equals_exact(ptown.union, tol) or expected2.equals_exact(ptown.union, tol))