Add Feature Extension for User Agent

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

@@ -207,6 +207,9 @@ internal bool IsDNSCachingBeforeRedirectSupported
         // Json Support Flag
         internal bool IsJsonSupportEnabled = false;
 
+        // User Agent Flag
+        internal bool IsUserAgentEnabled = true;
+
         // Vector Support Flag
         internal bool IsVectorSupportEnabled = false;
 
@@ -1430,6 +1433,10 @@ private void Login(ServerInfo server, TimeoutTimer timeout, string newPassword,
             requestedFeatures |= TdsEnums.FeatureExtension.JsonSupport;
             requestedFeatures |= TdsEnums.FeatureExtension.VectorSupport;
 
+        #if DEBUG
+            requestedFeatures |= TdsEnums.FeatureExtension.UserAgent;
+        #endif
+
             _parser.TdsLogin(login, requestedFeatures, _recoverySessionData, _fedAuthFeatureExtensionData, encrypt);
         }
 

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

@@ -8579,6 +8579,49 @@ internal int WriteVectorSupportFeatureRequest(bool write)
             return len;
         }
 
+        /// <summary>
+        /// Writes the User Agent feature request to the physical state object.
+        /// The request includes the feature ID, feature data length, version number and encoded JSON payload.
+        /// </summary>
+        /// <param name="userAgentJsonPayload"> Byte array of UTF-8 encoded JSON payload for User Agent</param>
+        /// <param name="write">
+        /// If true, writes the feature request to the physical state object.
+        /// If false, just calculates the length.
+        /// </param>
+        /// <returns>The length of the feature request in bytes.</returns>
+        /// <remarks>
+        /// The feature request consists of:
+        /// - 1 byte for the feature ID.
+        /// - 4 bytes for the feature data length.
+        /// - 1 byte for the version number.
+        /// - N bytes for the JSON payload
+        /// </remarks>
+        internal int WriteUserAgentFeatureRequest(byte[] userAgentJsonPayload,
+                                                  bool write)
+        {
+            // 1byte (Feature Version) + size of UTF-8 encoded JSON payload 
+            int dataLen = 1 + userAgentJsonPayload.Length;
+            // 1byte (Feature ID) + 4bytes (Feature Data Length) + 1byte (Version) + N(JSON payload size)
+            int totalLen = 1 + 4 + dataLen;
+
+            if (write)
+            {   
+                // Write Feature ID
+                _physicalStateObj.WriteByte(TdsEnums.FEATUREEXT_USERAGENT);
+
+                // Feature Data Length
+                WriteInt(dataLen, _physicalStateObj);
+
+                // Write Feature Version
+                _physicalStateObj.WriteByte(TdsEnums.SUPPORTED_USER_AGENT_VERSION);
+
+                // Write encoded JSON payload
+                _physicalStateObj.WriteByteArray(userAgentJsonPayload, userAgentJsonPayload.Length, 0);
+            }
+
+            return totalLen;
+        }
+
         private void WriteLoginData(SqlLogin rec,
                                      TdsEnums.FeatureExtension requestedFeatures,
                                      SessionData recoverySessionData,

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

@@ -211,6 +211,9 @@ internal bool IsDNSCachingBeforeRedirectSupported
         // Vector Support Flag
         internal bool IsVectorSupportEnabled = false;
 
+        // User Agent Flag
+        internal bool IsUserAgentEnabled = true;
+
         // TCE flags
         internal byte _tceVersionSupported;
 
@@ -1436,6 +1439,10 @@ private void Login(ServerInfo server, TimeoutTimer timeout, string newPassword,
             requestedFeatures |= TdsEnums.FeatureExtension.JsonSupport;
             requestedFeatures |= TdsEnums.FeatureExtension.VectorSupport;
 
+        #if DEBUG    
+            requestedFeatures |= TdsEnums.FeatureExtension.UserAgent;
+        #endif
+
             _parser.TdsLogin(login, requestedFeatures, _recoverySessionData, _fedAuthFeatureExtensionData, encrypt);
         }
 

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

@@ -8762,6 +8762,49 @@ internal int WriteVectorSupportFeatureRequest(bool write)
             return len;
         }
 
+        /// <summary>
+        /// Writes the User Agent feature request to the physical state object.
+        /// The request includes the feature ID, feature data length, version number and encoded JSON payload.
+        /// </summary>
+        /// <param name="userAgentJsonPayload"> Byte array of UTF-8 encoded JSON payload for User Agent</param>
+        /// <param name="write">
+        /// If true, writes the feature request to the physical state object.
+        /// If false, just calculates the length.
+        /// </param>
+        /// <returns>The length of the feature request in bytes.</returns>
+        /// <remarks>
+        /// The feature request consists of:
+        /// - 1 byte for the feature ID.
+        /// - 4 bytes for the feature data length.
+        /// - 1 byte for the version number.
+        /// - N bytes for the JSON payload
+        /// </remarks>
+        internal int WriteUserAgentFeatureRequest(byte[] userAgentJsonPayload,
+                                                  bool write)
+        {
+            // 1byte (Feature Version) + size of UTF-8 encoded JSON payload 
+            int dataLen = 1 + userAgentJsonPayload.Length;
+            // 1byte (Feature ID) + 4bytes (Feature Data Length) + 1byte (Version) + N(JSON payload size)
+            int totalLen = 1 + 4 + dataLen;
+
+            if (write)
+            {
+                // Write Feature ID
+                _physicalStateObj.WriteByte(TdsEnums.FEATUREEXT_USERAGENT);
+
+                // Feature Data Length
+                WriteInt(dataLen, _physicalStateObj);
+
+                // Write Feature Version
+                _physicalStateObj.WriteByte(TdsEnums.SUPPORTED_USER_AGENT_VERSION);
+
+                // Write encoded JSON payload
+                _physicalStateObj.WriteByteArray(userAgentJsonPayload, userAgentJsonPayload.Length, 0);
+            }
+
+            return totalLen;
+        }
+
         private void WriteLoginData(SqlLogin rec,
                                     TdsEnums.FeatureExtension requestedFeatures,
                                     SessionData recoverySessionData,

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

@@ -241,6 +241,8 @@ public enum EnvChangeType : byte
         public const byte FEATUREEXT_SQLDNSCACHING = 0x0B;
         public const byte FEATUREEXT_JSONSUPPORT = 0x0D;
         public const byte FEATUREEXT_VECTORSUPPORT = 0x0E;
+        // TODO: re-verify if this byte competes with another feature
+        public const byte FEATUREEXT_USERAGENT = 0x0F;
 
         [Flags]
         public enum FeatureExtension : uint
@@ -255,7 +257,8 @@ public enum FeatureExtension : uint
             UTF8Support = 1 << (TdsEnums.FEATUREEXT_UTF8SUPPORT - 1),
             SQLDNSCaching = 1 << (TdsEnums.FEATUREEXT_SQLDNSCACHING - 1),
             JsonSupport = 1 << (TdsEnums.FEATUREEXT_JSONSUPPORT - 1),
-            VectorSupport = 1 << (TdsEnums.FEATUREEXT_VECTORSUPPORT - 1)
+            VectorSupport = 1 << (TdsEnums.FEATUREEXT_VECTORSUPPORT - 1),
+            UserAgent = 1 << (TdsEnums.FEATUREEXT_USERAGENT - 1)
         }
 
         public const uint UTF8_IN_TDSCOLLATION = 0x4000000;
@@ -985,6 +988,9 @@ internal enum FedAuthInfoId : byte
         internal const byte MAX_SUPPORTED_VECTOR_VERSION = 0x01;
         internal const int VECTOR_HEADER_SIZE = 8;
 
+        // User Agent constants
+        internal const byte SUPPORTED_USER_AGENT_VERSION = 0x01;
+
         // TCE Related constants
         internal const byte MAX_SUPPORTED_TCE_VERSION = 0x03; // max version
         internal const byte MIN_TCE_VERSION_WITH_ENCLAVE_SUPPORT = 0x02; // min version with enclave support