Check for JSON feature extension

src/main/java/com/microsoft/sqlserver/jdbc/IOBuffer.java

@@ -169,6 +169,11 @@
     static final byte TDS_FEATURE_EXT_AZURESQLDNSCACHING = 0x0B;
     static final byte TDS_FEATURE_EXT_SESSIONRECOVERY = 0x01;
 
+    // JSON support
+    static final byte TDS_FEATURE_EXT_JSONSUPPORT = 0x0D;
+    static final byte JSONSUPPORT_NOT_SUPPORTED = 0x00;
+    static final byte MAX_JSONSUPPORT_VERSION = 0x01;
+
     static final int TDS_TVP = 0xF3;
     static final int TVP_ROW = 0x01;
     static final int TVP_NULL_TOKEN = 0xFFFF;
@@ -237,6 +242,9 @@
                 return "TDS_FEATURE_EXT_AZURESQLDNSCACHING (0x0B)";
             case TDS_FEATURE_EXT_SESSIONRECOVERY:
                 return "TDS_FEATURE_EXT_SESSIONRECOVERY (0x01)";
+            case TDS_FEATURE_EXT_JSONSUPPORT:
+                return "TDS_FEATURE_EXT_JSONSUPPORT (0x0D)";
+
             default:
                 return "unknown token (0x" + Integer.toHexString(tdsTokenType).toUpperCase() + ")";
         }

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerConnection.java

@@ -1021,6 +1021,16 @@
         return serverSupportedDataClassificationVersion;
     }
 
+    /** whether server supports JSON */
+    private boolean serverSupportsJSON = false;
+
+    /** server supported JSON version */
+    private byte serverSupportedJSONVersion = TDS.JSONSUPPORT_NOT_SUPPORTED;
+
+    boolean getServerSupportsJSON() {
+        return serverSupportsJSON;
+    }
+
     /** Boolean that indicates whether LOB objects created by this connection should be loaded into memory */
     private boolean delayLoadingLobs = SQLServerDriverBooleanProperty.DELAY_LOADING_LOBS.getDefaultValue();
 
@@ -5340,6 +5350,17 @@
         return len;
     }
 
+    int writeJSONSupportFeatureRequest(boolean write, /* if false just calculates the length */
+            TDSWriter tdsWriter) throws SQLServerException {
+        int len = 6; // 1byte = featureID, 4bytes = featureData length, 1 bytes = Version
+        if (write) {
+            tdsWriter.writeByte(TDS.TDS_FEATURE_EXT_JSONSUPPORT);
+            tdsWriter.writeInt(1);
+            tdsWriter.writeByte(TDS.MAX_JSONSUPPORT_VERSION);
+        }
+        return len;
+    }
+
     int writeIdleConnectionResiliencyRequest(boolean write, TDSWriter tdsWriter) throws SQLServerException {
         SessionStateTable ssTable = sessionRecovery.getSessionStateTable();
         int len = 1;
@@ -6469,6 +6490,24 @@
                 sessionRecovery.setConnectionRecoveryPossible(true);
                 break;
             }
+
+            case TDS.TDS_FEATURE_EXT_JSONSUPPORT: {
+                if (connectionlogger.isLoggable(Level.FINER)) {
+                    connectionlogger.fine(toString() + " Received feature extension acknowledgement for JSON Support.");
+                }
+
+                if (1 != data.length) {
+                    throw new SQLServerException(SQLServerException.getErrString("R_unknownJSONSupportValue"), null);
+                }
+
+                serverSupportedJSONVersion = data[0];
+                if (0 == serverSupportedJSONVersion || serverSupportedJSONVersion > TDS.MAX_JSONSUPPORT_VERSION) {
+                    throw new SQLServerException(SQLServerException.getErrString("R_InvalidJSONVersionNumber"), null);
+                }
+                serverSupportsJSON = true;
+                break;
+            }
+
             default: {
                 // Unknown feature ack
                 throw new SQLServerException(SQLServerException.getErrString("R_UnknownFeatureAck"), null);
@@ -6768,6 +6807,9 @@
 
         len = len + writeDNSCacheFeatureRequest(false, tdsWriter);
 
+        // request JSON support
+        len += writeJSONSupportFeatureRequest(false, tdsWriter);
+
         len = len + 1; // add 1 to length because of FeatureEx terminator
 
         // Idle Connection Resiliency is requested
@@ -6964,6 +7006,7 @@
         writeDataClassificationFeatureRequest(true, tdsWriter);
         writeUTF8SupportFeatureRequest(true, tdsWriter);
         writeDNSCacheFeatureRequest(true, tdsWriter);
+        writeJSONSupportFeatureRequest(true, tdsWriter);
 
         // Idle Connection Resiliency is requested
         if (connectRetryCount > 0) {

src/main/java/com/microsoft/sqlserver/jdbc/SQLServerResource.java

@@ -311,6 +311,7 @@ protected Object[][] getContents() {
         {"R_StreamingDataTypeAE", "Data of length greater than {0} is not supported in encrypted {1} column."},
         {"R_AE_NotSupportedByServer", "SQL Server in use does not support column encryption."},
         {"R_InvalidAEVersionNumber", "Received invalid version number \"{0}\" for Always Encrypted."}, // From server
+        {"R_InvalidJSONVersionNumber", "Received invalid version number \"{0}\" for JSON."},
         {"R_NullEncryptedColumnEncryptionKey", "Internal error. Encrypted column encryption key cannot be null."},
         {"R_EmptyEncryptedColumnEncryptionKey", "Internal error. Empty encrypted column encryption key specified."},
         {"R_InvalidMasterKeyDetails", "Invalid master key details specified."},
@@ -470,6 +471,7 @@ protected Object[][] getContents() {
         {"R_InvalidDataClsVersionNumber", "Invalid version number {0} for Data Classification."}, // From Server
         {"R_unknownUTF8SupportValue", "Unknown value for UTF8 support."},
         {"R_unknownAzureSQLDNSCachingValue", "Unknown value for Azure SQL DNS Caching."},
+        {"R_unknownJSONSupportValue", "Unknown value for JSON support."},
         {"R_illegalWKT", "Illegal Well-Known text. Please make sure Well-Known text is valid."},
         {"R_illegalTypeForGeometry", "{0} is not supported for Geometry."},
         {"R_illegalWKTposition", "Illegal character in Well-Known text at position {0}."},