Allow . as hostname in pipe names

src/System.Data.SqlClient/src/System/Data/SqlClient/SNI/SNIProxy.cs

@@ -2,17 +2,14 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Net;
 using System.Net.Security;
 using System.Net.Sockets;
 using System.Text;
 using System.Threading.Tasks;
-using System;
-using System.Threading;
-using System.Collections;
+using System.IO;
 
 namespace System.Data.SqlClient.SNI
 {
@@ -575,7 +572,6 @@ internal class DataSource
 
         private const char CommaSeparator = ',';
         private const char BackSlashSeparator = '\\';
-        private const char ForwardSlashSeparator = '/';
         private const string DefaultHostName = "localhost";
         private const string DefaultSqlServerInstanceName = "mssqlserver";
         private const string PipeBeginning = @"\\";
@@ -786,32 +782,44 @@ private bool InferNamedPipesInformation()
 
                 try
                 {
-                    Uri uri = new Uri(_dataSourceAfterTrimmingProtocol);
-                    if (string.IsNullOrEmpty(uri.Host))
+                    string[] tokensByBackSlash = _dataSourceAfterTrimmingProtocol.Split(BackSlashSeparator);
+
+                    // The datasource is of the format \\host\pipe\sql\query [0]\[1]\[2]\[3]\[4]\[5]
+                    // It would at least have 6 parts. 
+                    // Another valid Sql named pipe for an named instance is \\.\pipe\MSSQL$MYINSTANCE\sql\query
+                    if (tokensByBackSlash.Length < 6)
                     {
                         ReportSNIError(SNIProviders.NP_PROV);
                         return false;
                     }
 
-                    string[] absolutePathParts = uri.AbsolutePath.Split(ForwardSlashSeparator);
+                    string host = tokensByBackSlash[2];
 
-                    //Check if the "pipe" keyword is the first part of path
-                    if (PipeToken.CompareTo(absolutePathParts[1]) != 0)
+                    if (string.IsNullOrEmpty(host))
                     {
                         ReportSNIError(SNIProviders.NP_PROV);
                         return false;
                     }
 
-                    // There should be at least 4 parts in the pipename e.g /pipe/sql/query [0]/[1]/[2]/[3]
-                    // Another valid Sql named pipe for an named instance is \\.\pipe\MSSQL$MYINSTANCE\sql\query
-                    if (absolutePathParts.Length < 4)
+                    //Check if the "pipe" keyword is the first part of path
+                    if (!PipeToken.Equals(tokensByBackSlash[3]))
                     {
                         ReportSNIError(SNIProviders.NP_PROV);
                         return false;
                     }
 
-                    PipeName = uri.AbsolutePath.Substring(PipeToken.Length + 2);
-                    ServerName = IsLocalHost(uri.Host) ? Environment.MachineName : uri.Host;
+                    StringBuilder pipeNameBuilder = new StringBuilder();
+
+                    for ( int i = 4; i < tokensByBackSlash.Length-1; i++)
+                    {
+                        pipeNameBuilder.Append(tokensByBackSlash[i]);
+                        pipeNameBuilder.Append(Path.PathSeparator);
+                    }
+                    // Append the last part without a "/"
+                    pipeNameBuilder.Append(tokensByBackSlash[tokensByBackSlash.Length - 1]);
+
+                    PipeName = pipeNameBuilder.ToString();
+                    ServerName = IsLocalHost(host) ? Environment.MachineName : host;
                 }
                 catch (UriFormatException)
                 {
@@ -820,7 +828,7 @@ private bool InferNamedPipesInformation()
                 }
 
                 // DataSource is something like "\\pipename"
-                if (ConnectionProtocol != DataSource.Protocol.None)
+                if (ConnectionProtocol == DataSource.Protocol.None)
                 {
                     ConnectionProtocol = DataSource.Protocol.NP;
                 }

src/System.Data.SqlClient/tests/FunctionalTests/ExceptionTest.cs

@@ -76,6 +76,27 @@ public void IndependentConnectionExceptionTestExecuteReader()
             }
         }
 
+        [Theory]
+        [InlineData(@"np:\\.\pipe\sqlbad\query")]
+        [InlineData(@"np:\\.\pipe\MSSQL$NonExistentInstance\sql\query")]
+        [InlineData(@"\\.\pipe\sqlbad\query")]
+        [InlineData(@"\\.\pipe\MSSQL$NonExistentInstance\sql\query")]
+        [InlineData(@"np:\\localhost\pipe\sqlbad\query")]
+        [InlineData(@"np:\\localhost\pipe\MSSQL$NonExistentInstance\sqlbad\query")]
+        [InlineData(@"\\localhost\pipe\sqlbad\query")]
+        [InlineData(@"\\localhost\pipe\MSSQL$NonExistentInstance\sqlbad\query")]
+        [PlatformSpecific(TestPlatforms.Windows)] // Named pipes with the given input strings are not supported on Unix
+        public void NamedPipeTest(string dataSource)
+        {
+            SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
+            builder.DataSource = dataSource;
+            builder.ConnectTimeout = 1;
+            using(SqlConnection connection = new SqlConnection(builder.ConnectionString))
+            {
+                VerifyConnectionFailure<SqlException>(() => connection.Open(), "(provider: Named Pipes Provider, error: 11 - Timeout error)");
+            }
+        }
+
         private void GenerateConnectionException(string connectionString)
         {
             using (SqlConnection sqlConnection = new SqlConnection(connectionString))