added change database handler (#505)

src/Microsoft.SqlTools.ServiceLayer/Connection/ConnectionService.cs

@@ -863,6 +863,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
             serviceHost.SetRequestHandler(CancelConnectRequest.Type, HandleCancelConnectRequest);
             serviceHost.SetRequestHandler(DisconnectRequest.Type, HandleDisconnectRequest);
             serviceHost.SetRequestHandler(ListDatabasesRequest.Type, HandleListDatabasesRequest);
+            serviceHost.SetRequestHandler(ChangeDatabaseRequest.Type, HandleChangeDatabase);
         }
 
         /// <summary> 
@@ -1165,6 +1166,17 @@ namespace Microsoft.SqlTools.ServiceLayer.Connection
             return connectionBuilder;
         }
 
+        /// <summary>
+        /// Handles a request to change the database for a connection
+        /// </summary>
+        public async Task HandleChangeDatabase(
+            ChangeDatabaseParams changeDatabaseParams,
+            RequestContext<bool> requestContext)
+        {
+            ChangeConnectionDatabaseContext(changeDatabaseParams.OwnerUri, changeDatabaseParams.NewDatabase);
+            await requestContext.SendResult(true);
+        }
+
         /// <summary>
         /// Change the database context of a connection.
         /// </summary>

src/Microsoft.SqlTools.ServiceLayer/Connection/Contracts/ChangeDatabaseParams.cs

@@ -0,0 +1,23 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+namespace Microsoft.SqlTools.ServiceLayer.Connection.Contracts
+{
+    /// <summary>
+    /// Parameters for the List Databases Request.
+    /// </summary>
+    public class ChangeDatabaseParams
+    {
+        /// <summary>
+        /// URI of the owner of the connection requesting the list of databases.
+        /// </summary>
+        public string OwnerUri { get; set; }
+
+        /// <summary>
+        /// The database to change to
+        /// </summary>
+        public string NewDatabase { get; set; }
+    }
+}

src/Microsoft.SqlTools.ServiceLayer/Connection/Contracts/ChangeDatabaseRequest.cs

@@ -0,0 +1,19 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using Microsoft.SqlTools.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.Connection.Contracts
+{
+    /// <summary>
+    /// List databases request mapping entry 
+    /// </summary>
+    public class ChangeDatabaseRequest
+    {
+        public static readonly
+            RequestType<ChangeDatabaseParams, bool> Type =
+            RequestType<ChangeDatabaseParams, bool>.Create("connection/changedatabase");
+    }
+}