Fix named pipe path handling to preserve "."

namedpipe/namedpipe_windows.go

@@ -28,26 +28,34 @@ func (n namedPipeDialer) ParseServer(server string, p *msdsn.Config) error {
 	if strings.HasPrefix(server, `\\`) {
 		// assume a server name starting with \\ is the full named pipe path
 		p.ProtocolParameters[n.Protocol()] = namedPipeData{PipeName: server}
-	} else if p.Host == "" { // if the string specifies np:host\instance, tcpParser won't have filled in p.Host
+		return nil
+	}
+	pipeHost := "."
+	if p.Host == "" { // if the string specifies np:host\instance, tcpParser won't have filled in p.Host
 		parts := strings.SplitN(server, `\`, 2)
-		p.Host = parts[0]
-		if p.Host == "." || strings.ToUpper(p.Host) == "(LOCAL)" {
+		host := parts[0]
+		if host == "." || strings.ToUpper(host) == "(LOCAL)" {
+			// localhost replaces . to query the browser service but some SQL instances
+			// like Windows Internal Database require the . in the pipe name to connect
 			p.Host = "localhost"
+		} else {
+			p.Host = host
+			pipeHost = host
 		}
 		if len(parts) > 1 {
 			p.Instance = parts[1]
 		}
 	} else {
-		host := strings.ToLower(p.Host)
+		pipeHost = strings.ToLower(p.Host)
 		for _, domain := range azureDomains {
-			if strings.HasSuffix(host, domain) {
+			if strings.HasSuffix(pipeHost, domain) {
 				return fmt.Errorf("Named pipes disallowed for Azure SQL Database connections")
 			}
 		}
 	}
 	pipe, ok := p.Parameters["pipe"]
 	if ok {
-		p.ProtocolParameters[n.Protocol()] = namedPipeData{PipeName: fmt.Sprintf(`\\%s\pipe\%s`, p.Host, pipe)}
+		p.ProtocolParameters[n.Protocol()] = namedPipeData{PipeName: fmt.Sprintf(`\\%s\pipe\%s`, pipeHost, pipe)}
 	}
 	return nil
 }

namedpipe/namepipe_windows_test.go

@@ -0,0 +1,62 @@
+package namedpipe
+
+import (
+	"testing"
+
+	"github.com/microsoft/go-mssqldb/msdsn"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseServer(t *testing.T) {
+	c := &msdsn.Config{
+		Port: 1000,
+	}
+	n := &namedPipeDialer{}
+	err := n.ParseServer("server", c)
+	assert.Errorf(t, err, "ParseServer with a Port")
+
+	c = &msdsn.Config{
+		Parameters:         make(map[string]string),
+		ProtocolParameters: make(map[string]interface{}),
+	}
+	err = n.ParseServer(`\\.\pipe\MSSQL$Instance\sql\query`, c)
+	assert.NoError(t, err, "ParseServer with a full pipe name")
+	assert.Equal(t, "", c.Host, "Config Host with a full pipe name")
+	data, ok := c.ProtocolParameters[n.Protocol()]
+	assert.True(t, ok, "Should have added ProtocolParameters when server is pipe name")
+	switch d := data.(type) {
+	case namedPipeData:
+		assert.Equal(t, `\\.\pipe\MSSQL$Instance\sql\query`, d.PipeName, "Pipe name in ProtocolParameters when server is pipe name")
+	default:
+		assert.Fail(t, "Incorrect protocol parameters type:", d)
+	}
+
+	c = &msdsn.Config{
+		Parameters:         make(map[string]string),
+		ProtocolParameters: make(map[string]interface{}),
+	}
+	err = n.ParseServer(`.\instance`, c)
+	assert.NoError(t, err, "ParseServer .")
+	assert.Equal(t, "localhost", c.Host, `Config Host with server == .\instance`)
+	assert.Equal(t, "instance", c.Instance, `Config Instance with server == .\instance`)
+	_, ok = c.ProtocolParameters[n.Protocol()]
+	assert.Equal(t, ok, false, "Should have no namedPipeData when pipe name omitted")
+
+	c = &msdsn.Config{
+		Host:               "server",
+		Parameters:         make(map[string]string),
+		ProtocolParameters: make(map[string]interface{}),
+	}
+	c.Parameters["pipe"] = `myinstance\sql\query`
+	err = n.ParseServer(`anything`, c)
+	assert.NoError(t, err, "ParseServer anything")
+	data, ok = c.ProtocolParameters[n.Protocol()]
+	assert.True(t, ok, "Should have added ProtocolParameters when pipe name is provided")
+	switch d := data.(type) {
+	case namedPipeData:
+		assert.Equal(t, `\\server\pipe\myinstance\sql\query`, d.PipeName, "Pipe name in ProtocolParameters")
+	default:
+		assert.Fail(t, "Incorrect protocol parameters type:", d)
+	}
+
+}