Add Feature Extension for Json Support

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlInternalConnectionTds.cs

@@ -201,6 +201,9 @@ internal bool IsDNSCachingBeforeRedirectSupported
 
         internal SQLDNSInfo pendingSQLDNSObject = null;
 
+        // Json Support Flag
+        internal bool IsJsonSupportEnabled = false;
+
         // TCE flags
         internal byte _tceVersionSupported;
 
@@ -1365,6 +1368,8 @@ private void Login(ServerInfo server, TimeoutTimer timeout, string newPassword,
             // The SQLDNSCaching feature is implicitly set
             requestedFeatures |= TdsEnums.FeatureExtension.SQLDNSCaching;
 
+            requestedFeatures |= TdsEnums.FeatureExtension.JsonSupport;
+
             _parser.TdsLogin(login, requestedFeatures, _recoverySessionData, _fedAuthFeatureExtensionData, encrypt);
         }
 
@@ -2812,6 +2817,24 @@ internal void OnFeatureExtAck(int featureId, byte[] data)
                         break;
                     }
 
+                case TdsEnums.FEATUREEXT_JSONSUPPORT:
+                    {
+                        SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnectionTds.OnFeatureExtAck|ADV> {0}, Received feature extension acknowledgement for JSONSUPPORT", ObjectID);
+                        if (data.Length != 1)
+                        {
+                            SqlClientEventSource.Log.TryTraceEvent("<sc.SqlInternalConnectionTds.OnFeatureExtAck|ERR> {0}, Unknown token for JSONSUPPORT", ObjectID);
+                            throw SQL.ParsingError(ParsingErrorState.CorruptedTdsStream);
+                        }
+                        byte jsonSupportVersion = data[0];            
+                        if (jsonSupportVersion == 0 || jsonSupportVersion > 1)
+                        {
+                            SqlClientEventSource.Log.TryTraceEvent("<sc.SqlInternalConnectionTds.OnFeatureExtAck|ERR> {0}, Invalid version number for JSONSUPPORT", ObjectID);
+                            throw SQL.ParsingError();
+                        }
+                        IsJsonSupportEnabled = true;
+                        break;
+                    }
+
                 default:
                     {
                         // Unknown feature ack

src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParser.cs

@@ -8115,6 +8115,21 @@ internal int WriteFedAuthFeatureRequest(FederatedAuthenticationFeatureExtensionD
             return len;
         }
 
+        internal int WriteJsonSupportFeatureRequest(bool write /* if false just calculates the length */)
+        {
+            int len = 6; // 1byte = featureID, 4bytes = featureData length, 1 bytes = Version
+
+            if (write)
+            {
+                // Write Feature ID
+                _physicalStateObj.WriteByte(TdsEnums.FEATUREEXT_JSONSUPPORT);
+                WriteInt(1, _physicalStateObj);
+                _physicalStateObj.WriteByte(1);
+            }
+
+            return len;
+        }
+
         private void WriteLoginData(SqlLogin rec,
                                      TdsEnums.FeatureExtension requestedFeatures,
                                      SessionData recoverySessionData,
@@ -8425,6 +8440,11 @@ private int ApplyFeatureExData(TdsEnums.FeatureExtension requestedFeatures,
                     length += WriteSQLDNSCachingFeatureRequest(write);
                 }
 
+                if ((requestedFeatures & TdsEnums.FeatureExtension.JsonSupport) != 0)
+                {
+                    length += WriteJsonSupportFeatureRequest(write);
+                }
+
                 length++; // for terminator
                 if (write)
                 {

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/SqlInternalConnectionTds.cs

@@ -212,6 +212,9 @@ internal bool IsDNSCachingBeforeRedirectSupported
 
         internal SQLDNSInfo pendingSQLDNSObject = null;
 
+        // Json Support Flag
+        internal bool IsJsonSupportEnabled = false;
+
         // TCE flags
         internal byte _tceVersionSupported;
 
@@ -1638,6 +1641,8 @@ private void Login(ServerInfo server, TimeoutTimer timeout, string newPassword,
             // The SQLDNSCaching feature is implicitly set
             requestedFeatures |= TdsEnums.FeatureExtension.SQLDNSCaching;
 
+            requestedFeatures |= TdsEnums.FeatureExtension.JsonSupport;
+
             _parser.TdsLogin(login, requestedFeatures, _recoverySessionData, _fedAuthFeatureExtensionData, _originalNetworkAddressInfo, encrypt);
         }
 
@@ -3239,6 +3244,24 @@ internal void OnFeatureExtAck(int featureId, byte[] data)
                         break;
                     }
 
+                case TdsEnums.FEATUREEXT_JSONSUPPORT:
+                    {
+                        SqlClientEventSource.Log.TryAdvancedTraceEvent("<sc.SqlInternalConnectionTds.OnFeatureExtAck|ADV> {0}, Received feature extension acknowledgement for JSONSUPPORT", ObjectID);
+                        if (data.Length != 1)
+                        {
+                            SqlClientEventSource.Log.TryTraceEvent("<sc.SqlInternalConnectionTds.OnFeatureExtAck|ERR> {0}, Unknown token for JSONSUPPORT", ObjectID);
+                            throw SQL.ParsingError(ParsingErrorState.CorruptedTdsStream);
+                        }
+                        byte jsonSupportVersion = data[0];
+                        if (jsonSupportVersion == 0 || jsonSupportVersion > 1)
+                        {
+                            SqlClientEventSource.Log.TryTraceEvent("<sc.SqlInternalConnectionTds.OnFeatureExtAck|ERR> {0}, Invalid version number for JSONSUPPORT", ObjectID);
+                            throw SQL.ParsingError(ParsingErrorState.CorruptedTdsStream);
+                        }
+                        IsJsonSupportEnabled = true;
+                        break;
+                    }
+
                 default:
                     {
                         // Unknown feature ack

src/Microsoft.Data.SqlClient/netfx/src/Microsoft/Data/SqlClient/TdsParser.cs

@@ -8914,6 +8914,21 @@ internal int WriteFedAuthFeatureRequest(FederatedAuthenticationFeatureExtensionD
             return len;
         }
 
+        internal int WriteJsonSupportFeatureRequest(bool write /* if false just calculates the length */)
+        {
+            int len = 6; // 1byte = featureID, 4bytes = featureData length, 1 bytes = Version
+
+            if (write)
+            {
+                // Write Feature ID
+                _physicalStateObj.WriteByte(TdsEnums.FEATUREEXT_JSONSUPPORT);
+                WriteInt(1, _physicalStateObj);
+                _physicalStateObj.WriteByte(1);
+            }
+
+            return len;
+        }
+
         private void WriteLoginData(SqlLogin rec,
                                     TdsEnums.FeatureExtension requestedFeatures,
                                     SessionData recoverySessionData,
@@ -9241,6 +9256,11 @@ private int ApplyFeatureExData(TdsEnums.FeatureExtension requestedFeatures,
                         length += WriteSQLDNSCachingFeatureRequest(write);
                     }
 
+                    if ((requestedFeatures & TdsEnums.FeatureExtension.JsonSupport) != 0)
+                    {
+                        length += WriteJsonSupportFeatureRequest(write);
+                    }
+
                     length++; // for terminator
                     if (write)
                     {

src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/TdsEnums.cs

@@ -238,6 +238,7 @@ public enum EnvChangeType : byte
         public const byte FEATUREEXT_DATACLASSIFICATION = 0x09;
         public const byte FEATUREEXT_UTF8SUPPORT = 0x0A;
         public const byte FEATUREEXT_SQLDNSCACHING = 0x0B;
+        public const byte FEATUREEXT_JSONSUPPORT = 0x0D;
 
         [Flags]
         public enum FeatureExtension : uint
@@ -250,7 +251,8 @@ public enum FeatureExtension : uint
             AzureSQLSupport = 1 << (TdsEnums.FEATUREEXT_AZURESQLSUPPORT - 1),
             DataClassification = 1 << (TdsEnums.FEATUREEXT_DATACLASSIFICATION - 1),
             UTF8Support = 1 << (TdsEnums.FEATUREEXT_UTF8SUPPORT - 1),
-            SQLDNSCaching = 1 << (TdsEnums.FEATUREEXT_SQLDNSCACHING - 1)
+            SQLDNSCaching = 1 << (TdsEnums.FEATUREEXT_SQLDNSCACHING - 1),
+            JsonSupport = 1 << (TdsEnums.FEATUREEXT_JSONSUPPORT - 1)
         }
 
         public const uint UTF8_IN_TDSCOLLATION = 0x4000000;

src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.EndPoint/ITDSServerSession.cs

@@ -77,5 +77,10 @@ public interface ITDSServerSession
         /// Indicates whether this session supports transport-level recovery
         /// </summary>
         bool IsSessionRecoveryEnabled { get; set; }
+
+        /// <summary>
+        /// Indicates whether the client supports Json column type
+        /// </summary>
+        bool IsJsonSupportEnabled { get; set; }
     }
 }

src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.Servers/GenericTDSServer.cs

@@ -230,6 +230,12 @@ public virtual TDSMessageCollection OnLogin7Request(ITDSServerSession session, T
                                 // Save the fed auth library to be used
                                 (session as GenericTDSServerSession).FederatedAuthenticationLibrary = federatedAuthenticationOption.Library;
 
+                                break;
+                            }
+                        case TDSFeatureID.JsonSupport:
+                            {
+                                // Enable Json Support
+                                session.IsJsonSupportEnabled = true;
                                 break;
                             }
                         default:
@@ -544,6 +550,32 @@ protected virtual TDSMessageCollection OnAuthenticationCompleted(ITDSServerSessi
                 responseMessage.Add(featureExtActToken);
             }
 
+            // Check if Json is supported
+            if (session.IsJsonSupportEnabled)
+            {
+                // Create ack data (1 byte: Version number)
+                byte[] data = new byte[1];
+                data[0] = (byte)1;
+
+                // Create Json support as a generic feature extension option
+                TDSFeatureExtAckGenericOption jsonSupportOption = new TDSFeatureExtAckGenericOption(TDSFeatureID.JsonSupport, (uint)data.Length, data);
+
+                // Look for feature extension token
+                TDSFeatureExtAckToken featureExtAckToken = (TDSFeatureExtAckToken)responseMessage.Where(t => t is TDSFeatureExtAckToken).FirstOrDefault();
+
+                if (featureExtAckToken == null)
+                {
+                    // Create feature extension ack token
+                    featureExtAckToken = new TDSFeatureExtAckToken(jsonSupportOption);
+                    responseMessage.Add(featureExtAckToken);
+                }
+                else
+                {
+                    // Update the existing token
+                    featureExtAckToken.Options.Add(jsonSupportOption);
+                }
+            }
+
             // Create DONE token
             TDSDoneToken doneToken = new TDSDoneToken(TDSDoneTokenStatusType.Final);
 

src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS.Servers/GenericTDSServerSession.cs

@@ -108,6 +108,11 @@ public class GenericTDSServerSession : ITDSServerSession
         /// </summary>
         public bool IsSessionRecoveryEnabled { get; set; }
 
+        /// <summary>
+        /// Indicates whether this session supports Json column type
+        /// </summary>
+        public bool IsJsonSupportEnabled { get; set; }
+
         #region Session Options
 
         /// <summary>

src/Microsoft.Data.SqlClient/tests/tools/TDS/TDS/TDSFeatureID.cs

@@ -19,6 +19,11 @@ public enum TDSFeatureID : byte
         /// </summary>
         FederatedAuthentication = 0x02,
 
+        /// <summary>
+        /// JSON Support
+        /// </summary>
+        JsonSupport = 0x0D,
+
         /// <summary>
         /// End of the list
         /// </summary>