Add "Application Name" connection string setting. Fixes #547

Author: bgrainger

docs/content/connection-options.md

@@ -1,5 +1,5 @@
 ---
-lastmod: 2017-11-06
+lastmod: 2018-08-21
 date: 2016-10-16
 title: Connection Options
 weight: 30
@@ -205,6 +205,12 @@ These are the other options that MySqlConnector supports. They are set to sensib
     This allows the special “zero” date value `0000-00-00` to be retrieved from the database. If <code>false</code> (the default)
     date columns are returned as `DateTime` values, and an exception is thrown for unrepresentable dates.</td>
   </tr>
+  <tr>
+    <td>ApplicationName, Application Name</td>
+    <td>null</td>
+    <td>Sets the <c>program_name</c> connection attribute passed to MySQL Server. This value may be displayed by diagnostic tools,
+    e.g., as the “Program” column in “Client Connections” in <a href="https://www.mysql.com/products/workbench/">MySQL Workbench</a>.</td>
+  </tr>
   <tr>
     <td>Compress, Use Compression, UseCompression</td>
     <td>false</td>

src/MySqlConnector/Core/ConnectionSettings.cs

@@ -65,6 +65,7 @@ public ConnectionSettings(MySqlConnectionStringBuilder csb)
 			AllowPublicKeyRetrieval = csb.AllowPublicKeyRetrieval;
 			AllowUserVariables = csb.AllowUserVariables;
 			AllowZeroDateTime = csb.AllowZeroDateTime;
+			ApplicationName = csb.ApplicationName;
 			AutoEnlist = csb.AutoEnlist;
 			ConnectionTimeout = (int) csb.ConnectionTimeout;
 			ConvertZeroDateTime = csb.ConvertZeroDateTime;
@@ -142,6 +143,7 @@ private static MySqlGuidFormat GetEffectiveGuidFormat(MySqlGuidFormat guidFormat
 		public bool AllowPublicKeyRetrieval { get; }
 		public bool AllowUserVariables { get; }
 		public bool AllowZeroDateTime { get; }
+		public string ApplicationName { get; }
 		public bool AutoEnlist { get; }
 		public int ConnectionTimeout { get; }
 		public bool ConvertZeroDateTime { get; }
@@ -159,6 +161,8 @@ private static MySqlGuidFormat GetEffectiveGuidFormat(MySqlGuidFormat guidFormat
 		public bool UseAffectedRows { get; }
 		public bool UseCompression { get; }
 
+		public byte[] ConnectionAttributes { get; set; }
+
 		// Helper Functions
 		int? m_connectionTimeoutMilliseconds;
 		public int ConnectionTimeoutMilliseconds

src/MySqlConnector/Core/ServerSession.cs

@@ -328,10 +328,10 @@ public async Task ConnectAsync(ConnectionSettings cs, ILoadBalancer loadBalancer
 					}
 				} while (shouldRetrySsl);
 
-				if (m_supportsConnectionAttributes && s_connectionAttributes == null)
-					s_connectionAttributes = CreateConnectionAttributes();
+				if (m_supportsConnectionAttributes && cs.ConnectionAttributes == null)
+					cs.ConnectionAttributes = CreateConnectionAttributes(cs.ApplicationName);
 
-				using (var handshakeResponsePayload = HandshakeResponse41Payload.Create(initialHandshake, cs, m_useCompression, m_supportsConnectionAttributes ? s_connectionAttributes : null))
+				using (var handshakeResponsePayload = HandshakeResponse41Payload.Create(initialHandshake, cs, m_useCompression, m_supportsConnectionAttributes ? cs.ConnectionAttributes : null))
 					await SendReplyAsync(handshakeResponsePayload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 
@@ -395,7 +395,7 @@ public async Task<bool> TryResetConnectionAsync(ConnectionSettings cs, IOBehavio
 						DatabaseOverride = null;
 					}
 					var hashedPassword = AuthenticationUtility.CreateAuthenticationResponse(AuthPluginData, 0, cs.Password);
-					using (var changeUserPayload = ChangeUserPayload.Create(cs.UserID, hashedPassword, cs.Database, m_supportsConnectionAttributes ? s_connectionAttributes : null))
+					using (var changeUserPayload = ChangeUserPayload.Create(cs.UserID, hashedPassword, cs.Database, m_supportsConnectionAttributes ? cs.ConnectionAttributes : null))
 						await SendAsync(changeUserPayload, ioBehavior, cancellationToken).ConfigureAwait(false);
 					var payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 					if (payload.HeaderByte == AuthenticationMethodSwitchRequestPayload.Signature)
@@ -1269,7 +1269,7 @@ private void VerifyState(State state1, State state2, State state3)
 
 		internal SslProtocols SslProtocol => m_sslStream?.SslProtocol ?? SslProtocols.None;
 
-		private byte[] CreateConnectionAttributes()
+		private byte[] CreateConnectionAttributes(string programName)
 		{
 			Log.Debug("Session{0} creating connection attributes", m_logArguments);
 			var attributesWriter = new ByteBufferWriter();
@@ -1298,6 +1298,11 @@ private byte[] CreateConnectionAttributes()
 				attributesWriter.WriteLengthEncodedString("_pid");
 				attributesWriter.WriteLengthEncodedString(process.Id.ToString(CultureInfo.InvariantCulture));
 			}
+			if (!string.IsNullOrEmpty(programName))
+			{
+				attributesWriter.WriteLengthEncodedString("program_name");
+				attributesWriter.WriteLengthEncodedString(programName);
+			}
 			using (var connectionAttributesPayload = attributesWriter.ToPayloadData())
 			{
 				var connectionAttributes = connectionAttributesPayload.ArraySegment;
@@ -1349,7 +1354,6 @@ private enum State
 
 		static readonly byte[] s_beginCertificateBytes = new byte[] { 45, 45, 45, 45, 45, 66, 69, 71, 73, 78, 32, 67, 69, 82, 84, 73, 70, 73, 67, 65, 84, 69, 45, 45, 45, 45, 45 }; // -----BEGIN CERTIFICATE-----
 		static int s_lastId;
-		static byte[] s_connectionAttributes;
 		static readonly IMySqlConnectorLogger Log = MySqlConnectorLogManager.CreateLogger(nameof(ServerSession));
 		static readonly PayloadData s_setNamesUtf8mb4Payload = QueryPayload.Create("SET NAMES utf8mb4 COLLATE utf8mb4_bin;");
 

src/MySqlConnector/MySql.Data.MySqlClient/MySqlConnectionStringBuilder.cs

@@ -165,6 +165,12 @@ public bool AllowZeroDateTime
 			set => MySqlConnectionStringOption.AllowZeroDateTime.SetValue(this, value);
 		}
 
+		public string ApplicationName
+		{
+			get => MySqlConnectionStringOption.ApplicationName.GetValue(this);
+			set => MySqlConnectionStringOption.ApplicationName.SetValue(this, value);
+		}
+
 		public bool AutoEnlist
 		{
 			get => MySqlConnectionStringOption.AutoEnlist.GetValue(this);
@@ -349,6 +355,7 @@ internal abstract class MySqlConnectionStringOption
 		public static readonly MySqlConnectionStringOption<bool> AllowPublicKeyRetrieval;
 		public static readonly MySqlConnectionStringOption<bool> AllowUserVariables;
 		public static readonly MySqlConnectionStringOption<bool> AllowZeroDateTime;
+		public static readonly MySqlConnectionStringOption<string> ApplicationName;
 		public static readonly MySqlConnectionStringOption<bool> AutoEnlist;
 		public static readonly MySqlConnectionStringOption<string> CharacterSet;
 		public static readonly MySqlConnectionStringOption<uint> ConnectionTimeout;
@@ -494,6 +501,10 @@ static MySqlConnectionStringOption()
 				keys: new[] { "AllowZeroDateTime", "Allow Zero DateTime" },
 				defaultValue: false));
 
+			AddOption(ApplicationName = new MySqlConnectionStringOption<string>(
+				keys: new[] { "ApplicationName", "Application Name" },
+				defaultValue: null));
+
 			AddOption(AutoEnlist = new MySqlConnectionStringOption<bool>(
 				keys: new[] { "AutoEnlist", "Auto Enlist" },
 				defaultValue: true));

tests/MySqlConnector.Tests/MySqlConnectionStringBuilderTests.cs

@@ -34,12 +34,11 @@ public void Defaults()
 			Assert.Equal("", csb.Database);
 			Assert.Equal(30u, csb.DefaultCommandTimeout);
 #if !BASELINE
+			Assert.Null(csb.ApplicationName);
 			Assert.Equal(0u, csb.ConnectionIdlePingTime);
 			Assert.Equal(180u, csb.ConnectionIdleTimeout);
 			Assert.False(csb.ForceSynchronous);
-#if !BASELINE
 			Assert.Equal(MySqlGuidFormat.Default, csb.GuidFormat);
-#endif
 			Assert.False(csb.IgnoreCommandTransaction);
 			Assert.Null(csb.CACertificateFile);
 			Assert.Equal(MySqlLoadBalance.RoundRobin, csb.LoadBalance);
@@ -100,6 +99,7 @@ public void ParseConnectionString()
 #endif
 					"default command timeout=123;" +
 #if !BASELINE
+					"application name=My Test Application;" +
 					"connection idle ping time=60;" +
 					"connectionidletimeout=30;" +
 					"forcesynchronous=true;" +
@@ -146,6 +146,7 @@ public void ParseConnectionString()
 			Assert.Equal("schema_name", csb.Database);
 			Assert.Equal(123u, csb.DefaultCommandTimeout);
 #if !BASELINE
+			Assert.Equal("My Test Application", csb.ApplicationName);
 			Assert.Equal(60u, csb.ConnectionIdlePingTime);
 			Assert.Equal(30u, csb.ConnectionIdleTimeout);
 			Assert.True(csb.ForceSynchronous);