Use Npgsql's PostGIS/NTS plug-in for Geometry type

Author: Peet Whittaker

NHibernate.Spatial.PostGis/NHibernate.Spatial.PostGis.csproj

@@ -29,7 +29,8 @@
 
   <ItemGroup>
     <PackageReference Include="NetTopologySuite.IO.PostGis" Version="2.1.0" />
-    <PackageReference Include="Npgsql" Version="[3.2.7, 4.0)" />
+    <PackageReference Include="Npgsql" Version="4.1.12" />
+    <PackageReference Include="Npgsql.NetTopologySuite" Version="4.1.12" />
   </ItemGroup>
 
   <ItemGroup>

NHibernate.Spatial.PostGis/Type/PostGisGeometryType.cs

@@ -15,10 +15,9 @@
 // along with NHibernate.Spatial; if not, write to the Free Software
 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
-using NetTopologySuite.Geometries;
-using NetTopologySuite.IO;
 using System;
 using System.Data.Common;
+using NetTopologySuite.Geometries;
 using NHibernate.Engine;
 using NHibernate.SqlTypes;
 using NHibernate.Type;
@@ -28,7 +27,7 @@
 namespace NHibernate.Spatial.Type
 {
     [Serializable]
-    public class PostGisGeometryType : GeometryTypeBase<byte[]>
+    public class PostGisGeometryType : GeometryTypeBase<Geometry>
     {
         private static readonly NullableType GeometryType = new CustomGeometryType();
 
@@ -45,45 +44,17 @@ public PostGisGeometryType()
         /// </summary>
         /// <param name="value">The GeoAPI geometry value.</param>
         /// <returns></returns>
-        protected override byte[] FromGeometry(object value)
+        protected override Geometry FromGeometry(object value)
         {
-            Geometry geometry = value as Geometry;
+            var geometry = value as Geometry;
             if (geometry == null)
             {
                 return null;
             }
-            // PostGIS can't parse a WKB of any empty geometry other than GeomtryCollection
-            // (throws the error: "geometry requires more points")
-            // and parses WKT of empty geometries always as GeometryCollection
-            // (ie. "select AsText(GeomFromText('LINESTRING EMPTY', -1)) = 'GEOMETRYCOLLECTION EMPTY'").
-            // Force GeometryCollection.Empty to avoid the error.
-            if (!(geometry is GeometryCollection) && geometry.IsEmpty)
-            {
-                geometry = GeometryCollection.Empty;
-            }
 
             this.SetDefaultSRID(geometry);
 
-            // Determine the ordinality of the geometry to ensure 3D and 4D geometries are
-            // correctly serialized by PostGisWriter (see issue #66)
-            // NOTE: Cannot use InteriorPoint here as that always returns a 2D point (see #120)
-            // TODO: Is there a way of getting the ordinates directly from the geometry?
-            var ordinates = Ordinates.XY;
-            var coordinate = geometry.Coordinate;
-            if (coordinate != null && !double.IsNaN(coordinate.Z))
-            {
-                ordinates |= Ordinates.Z;
-            }
-            if (coordinate != null && !double.IsNaN(coordinate.M))
-            {
-                ordinates |= Ordinates.M;
-            }
-
-            var postGisWriter = new PostGisWriter
-            {
-                HandleOrdinates = ordinates
-            };
-            return postGisWriter.Write(geometry);
+            return geometry;
         }
 
         /// <summary>
@@ -93,15 +64,14 @@ protected override byte[] FromGeometry(object value)
         /// <returns></returns>
         protected override Geometry ToGeometry(object value)
         {
-            var bytes = value as byte[];
-            if (bytes == null)
+            var geometry = value as Geometry;
+            if (geometry == null)
             {
                 return null;
             }
 
-            PostGisReader reader = new PostGisReader();
-            Geometry geometry = reader.Read(bytes);
             this.SetDefaultSRID(geometry);
+
             return geometry;
         }
 
@@ -114,16 +84,7 @@ internal CustomGeometryType() : base(new BinarySqlType())
 
             public override object Get(DbDataReader rs, int index, ISessionImplementor session)
             {
-                // Npgsql 3 from the received bytes creates his own PostGisGeometry type.
-                // As we need to return a byte array that represents the geometry object,
-                // we will retrive the bytes from the reader instead.
-                var length = (int)rs.GetBytes(index, 0, null, 0, 0);
-                var buffer = new byte[length];
-                if (length > 0)
-                {
-                    rs.GetBytes(index, 0, buffer, 0, length);
-                }
-                return buffer;
+                return (Geometry)rs.GetValue(index);
             }
 
             public override object Get(DbDataReader rs, string name, ISessionImplementor session)
@@ -144,8 +105,8 @@ public override void Set(DbCommand cmd, object value, int index, ISessionImpleme
 
             public override object DeepCopyNotNull(object value)
             {
-                var arr = (byte[]) value;
-                return arr.Clone();
+                var obj = (Geometry)value;
+                return obj.Copy();
             }
         }
     }

NetTopologySuite.TestRunner/Utility/WKTOrWKBReader.cs

@@ -37,7 +37,10 @@ private static Boolean IsHexDigit(char ch)
 
         public WKTOrWKBReader(NtsGeometryServices ntsGeometryServices)
         {
-            _wktReader = new WKTReader(ntsGeometryServices);
+            _wktReader = new WKTReader(ntsGeometryServices)
+            {
+                IsOldNtsCoordinateSyntaxAllowed = false
+            };
 #pragma warning disable 612
             _wkbReader = new WKBReader();
 #pragma warning restore 612

Tests.NHibernate.Spatial.PostGis/TestConfiguration.cs

@@ -3,6 +3,7 @@
 using NHibernate.Cfg;
 using NHibernate.Driver;
 using NHibernate.Spatial.Dialect;
+using Npgsql;
 using System.Collections.Generic;
 
 namespace Tests.NHibernate.Spatial
@@ -29,6 +30,10 @@ public static void Configure(Configuration configuration)
                 [Environment.ConnectionString] = _configurationRoot.GetConnectionString("PostGis")
             };
             configuration.SetProperties(properties);
+
+            // Use NTS plugin for mapping PostGIS types; see:
+            // https://www.npgsql.org/doc/release-notes/4.0.html#improved-spatial-support-postgis
+            NpgsqlConnection.GlobalTypeMapper.UseNetTopologySuite();
         }
     }
 }

Tests.NHibernate.Spatial.PostGis20/TestConfiguration.cs

@@ -3,6 +3,7 @@
 using NHibernate.Cfg;
 using NHibernate.Driver;
 using NHibernate.Spatial.Dialect;
+using Npgsql;
 using System.Collections.Generic;
 
 namespace Tests.NHibernate.Spatial
@@ -29,6 +30,10 @@ public static void Configure(Configuration configuration)
                 [Environment.ConnectionString] = _configurationRoot.GetConnectionString("PostGis20")
             };
             configuration.SetProperties(properties);
+
+            // Use NTS plugin for mapping PostGIS types; see:
+            // https://www.npgsql.org/doc/release-notes/4.0.html#improved-spatial-support-postgis
+            NpgsqlConnection.GlobalTypeMapper.UseNetTopologySuite();
         }
     }
 }

Tests.NHibernate.Spatial/AbstractFixture.cs

@@ -24,7 +24,10 @@ namespace Tests.NHibernate.Spatial
     public abstract class AbstractFixture
     {
         private static readonly ILog Log = LogManager.GetLogger(typeof(AbstractFixture));
-        protected static readonly WKTReader Wkt = new WKTReader();
+        protected static readonly WKTReader Wkt = new WKTReader()
+        {
+            IsOldNtsCoordinateSyntaxAllowed = false
+        };
         protected Configuration configuration;
         protected ISessionFactory sessions;
         private ISpatialDialect spatialDialect;