Add a converter to serialize properly DBNull value (#477)

* Add a converter to serialize properly the DBNull value according to the suggestion in dotnet/runtime#418
Move duplicate code in GxRedis.cs and GxMemcached.cs to GxClasses.csproj
Adding the package reference System.Text.Json to GxClasses.csproj gets a conflict with System.Net.Http. Because of that, HttpClient used in MapFunctions.cs is replaced by HttpWebRequest for .netframework similar to the use in GXGeolocation.

* Remove unused code.

(cherry picked from commit fbfe50c)

Author: claudiamurialdo

.gitignore

@@ -358,3 +358,6 @@ build
 /dotnet/src/dotnetcore/GxNetCoreStartup/netcoreapp3.1/GxNetCoreStartup.deps.json
 /dotnet/src/dotnetcore/Reor/net5.0/Reor.deps.json
 /dotnet/src/dotnetcore/Reor/netcoreapp3.1/Reor.deps.json
+/dotnet/src/dotnetcore/GxDataInitialization/net6.0/GXDataInitialization.deps.json
+/dotnet/src/dotnetcore/GxNetCoreStartup/net6.0/GxNetCoreStartup.deps.json
+/dotnet/src/dotnetcore/Reor/net6.0/Reor.deps.json

dotnet/src/dotnetframework/GxClasses/Data/GXDataCommon.cs

@@ -4298,7 +4298,7 @@ public object GetValue(int i)
 		}
 		public virtual bool IsDBNull(int i)
 		{
-			return (block.Item(pos, i) == DBNull.Value) || (block.Item(pos, i) is DBNull);
+			return (block.Item(pos, i) == DBNull.Value) || (block.Item(pos, i) is DBNull || block.Item(pos, i) == null);
 		}
 		public char GetChar(int i)
 		{

dotnet/src/dotnetframework/GxClasses/Domain/GXGeolocation.cs

@@ -10,7 +10,9 @@
 using System.Globalization;
 using GeneXus;
 using GeneXus.Configuration;
+#if NETCORE
 using System.Net.Http;
+#endif
 
 namespace GX
 {

dotnet/src/dotnetframework/GxClasses/GxClasses.csproj

@@ -18,6 +18,7 @@
 		<PackageReference Include="Nustache" Version="1.16.0.10" />
 		<PackageReference Include="SecurityCodeScan" PrivateAssets="all" Version="3.3.0" />
 		<PackageReference Include="log4net" Version="2.0.11" />
+		<PackageReference Include="System.Text.Json" Version="5.0.2" />
 		<Reference Include="Microsoft.HostIntegration.MsDb2Client">
 			<SpecificVersion>False</SpecificVersion>
 			<HintPath>..\libs\Microsoft.HostIntegration.MsDb2Client.dll</HintPath>

dotnet/src/dotnetframework/GxClasses/Services/Caching/GxCache.cs

@@ -12,6 +12,9 @@
 using System.Collections.Generic;
 using GeneXus.Services;
 using System.Linq;
+using System.Security;
+using System.Text.Json.Serialization;
+using System.Text.Json;
 #if NETCORE
 using GxClasses.Helpers;
 using System.IO;
@@ -37,6 +40,58 @@ public interface ICacheService2 : ICacheService
 		IDictionary<string, T> GetAll<T>(string cacheid, IEnumerable<string> keys);
 		void SetAll<T>(string cacheid, IEnumerable<string> keys, IEnumerable<T> values, int durationMinutes = 0);
 	}
+	[SecurityCritical]
+	public class DBNullConverter : JsonConverter<DBNull>
+	{
+		[SecurityCritical]
+		public override DBNull Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+		{
+			throw new NotSupportedException();
+		}
+		[SecurityCritical]
+		public override void Write(Utf8JsonWriter writer, DBNull value, JsonSerializerOptions options)
+		{
+			writer.WriteNullValue();
+		}
+	}
+	[SecurityCritical]
+	public class ObjectToInferredTypesConverter : JsonConverter<object>
+	{
+		[SecurityCritical]
+		public override bool CanConvert(Type typeToConvert)
+		{
+			return typeof(object) == typeToConvert;
+		}
+		[SecurityCritical]
+		public override object Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+		{
+			switch (reader.TokenType)
+			{
+				case JsonTokenType.True:
+					return true;
+				case JsonTokenType.False:
+					return false;
+				case JsonTokenType.Number:
+					if (reader.TryGetInt64(out long l))
+						return l;
+					else return reader.GetDouble();
+				case JsonTokenType.String:
+					if (reader.TryGetDateTime(out DateTime datetime))
+						return datetime;
+					else return reader.GetString();
+				default:
+					using (JsonDocument document = JsonDocument.ParseValue(ref reader))
+					{
+						return document.RootElement.Clone().ToString();
+					}
+			}
+		}
+		[SecurityCritical]
+		public override void Write(Utf8JsonWriter writer, object value, JsonSerializerOptions options)
+		{
+			throw new NotImplementedException();
+		}
+	}
 
 	public class CacheFactory
     {

dotnet/src/dotnetframework/GxMaps/MapFunctions.cs

@@ -7,7 +7,6 @@
 using GeneXus.Utils;
 using System.IO;
 using System.Globalization;
-using System.Net.Http;
 
 namespace GeneXus.MapServices
 {
@@ -118,21 +117,6 @@ private static Assembly LoadAssembly(string fileName)
 
 		public static LocationInfo GetCurrentLocation(int minAccuracy, int timeout, bool includeHAndS, bool ignoreErrors)
 		{
-			if (Application.GxContext.IsHttpContext)
-			{
-				string ip = Application.GxContext.Current.GetRemoteAddress();
-				using (HttpClient client = new HttpClient())
-				{
-					using (HttpResponseMessage response = client.GetAsync(new Uri("http://ipinfo.io/" + ip)).Result)
-					{
-						using (HttpContent content = response.Content)
-						{
-							string info = content.ReadAsStringAsync().Result;
-						}
-					}
-				}
-				return new LocationInfo { };
-			}
 			return new LocationInfo { };
 		}
 

dotnet/src/dotnetframework/Providers/Cache/GxMemcached/GxMemcached.cs

@@ -215,7 +215,9 @@ static string Serialize(object o)
 			{
 				return null;
 			}
-			return JsonSerializer.Serialize(o);
+			JsonSerializerOptions opts = new JsonSerializerOptions();
+			opts.Converters.Add(new DBNullConverter());
+			return JsonSerializer.Serialize(o, opts);
 		}
 		[SecurityCritical]
 		static T Deserialize<T>(string value)
@@ -229,43 +231,4 @@ static T Deserialize<T>(string value)
 			return JsonSerializer.Deserialize<T>(value, opts);
 		}
 	}
-	[SecurityCritical]
-	public class ObjectToInferredTypesConverter : JsonConverter<object>
-	{
-		[SecurityCritical]
-		public override bool CanConvert(Type typeToConvert)
-		{
-			return typeof(object) == typeToConvert;
-		}
-		[SecurityCritical]
-		public override object Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-		{
-			switch (reader.TokenType)
-			{
-				case JsonTokenType.True:
-					return true;
-				case JsonTokenType.False:
-					return false;
-				case JsonTokenType.Number:
-					if (reader.TryGetInt64(out long l))
-						return l;
-					else return reader.GetDouble();
-				case JsonTokenType.String:
-					if (reader.TryGetDateTime(out DateTime datetime))
-						return datetime;
-					else return reader.GetString();
-				default:
-					using (JsonDocument document = JsonDocument.ParseValue(ref reader))
-					{
-						return document.RootElement.Clone().ToString();
-					}
-			}
-		}
-		[SecurityCritical]
-		public override void Write(Utf8JsonWriter writer, object value, JsonSerializerOptions options)
-		{
-			throw new NotImplementedException();
-		}
-	}
-
 }

dotnet/src/dotnetframework/Providers/Cache/GxRedis/GxRedis.cs

@@ -205,7 +205,9 @@ static string Serialize(object o)
 			{
 				return null;
 			}
-			return JsonSerializer.Serialize(o);
+			JsonSerializerOptions opts = new JsonSerializerOptions();
+			opts.Converters.Add(new DBNullConverter());
+			return JsonSerializer.Serialize(o, opts);
 		}
 
 		static T Deserialize<T>(string value)
@@ -219,39 +221,4 @@ static T Deserialize<T>(string value)
 			return JsonSerializer.Deserialize<T>(value, opts);
 		}
 	}
-	public class ObjectToInferredTypesConverter: JsonConverter<object>
-	{
-		public override bool CanConvert(Type typeToConvert)
-		{
-			return typeof(object) == typeToConvert;
-		}
-		public override object Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
-		{
-			switch (reader.TokenType)
-			{
-				case JsonTokenType.True:
-					return true;
-				case JsonTokenType.False:
-					return false;
-				case JsonTokenType.Number:
-					if (reader.TryGetInt64(out long l))
-						return l;
-					else return reader.GetDouble();
-				case JsonTokenType.String:
-					if (reader.TryGetDateTime(out DateTime datetime))
-						return datetime;
-					else return reader.GetString();
-				default:
-					using (JsonDocument document = JsonDocument.ParseValue(ref reader))
-					{
-						return document.RootElement.Clone().ToString();
-					}
-			}
-		}
-
-		public override void Write(Utf8JsonWriter writer, object value, JsonSerializerOptions options)
-		{
-			throw new NotImplementedException();
-		}
-	}
 }