Merge pull request 'Open tcp connection for every read.' (#1) from move-dial-to-read-registers into master

client.go

@@ -10,24 +10,27 @@ import (
 
 type Mbclient struct {
 	transactionCounter uint16
-	conn               net.Conn
+	address            string
 	header             [7]byte
 	unit               uint8
 }
 
 func New(address string, unit uint8) (*Mbclient, error) {
-	var err error
 
 	c := new(Mbclient)
-	c.conn, err = net.Dial("tcp", address)
-	if err != nil {
-		return nil, err
-	}
+	c.address = address
 	c.unit = unit
 	return c, nil
 }
 
 func (m *Mbclient) ReadRegisters(first uint16, numRegs uint16) ([]uint16, error) {
+
+	conn, err := net.Dial("tcp", m.address)
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
 	const requestLength = 12
 	m.transactionCounter++
 	req := make([]byte, requestLength)
@@ -41,21 +44,21 @@ func (m *Mbclient) ReadRegisters(first uint16, numRegs uint16) ([]uint16, error)
 	req[7] = 3 //FunctionCode
 	binary.BigEndian.PutUint16(req[8:10], first-1)
 	binary.BigEndian.PutUint16(req[10:12], numRegs)
-	m.conn.SetDeadline(time.Now().Add(10 * time.Second))
-	byteswritten, err := m.conn.Write(req)
+	conn.SetDeadline(time.Now().Add(10 * time.Second))
+	byteswritten, err := conn.Write(req)
 	if err != nil {
 		return nil, err
 	}
 	if byteswritten != requestLength {
 		return nil, fmt.Errorf("Failed to send request")
 	}
-	m.conn.SetDeadline(time.Now().Add(10 * time.Second))
-	_, err = io.ReadFull(m.conn, m.header[:])
+	conn.SetDeadline(time.Now().Add(10 * time.Second))
+	_, err = io.ReadFull(conn, m.header[:])
 	responseHeader.unMarshal(m.header)
 	expectedDataLength := responseHeader.length - 1
 
 	response := make([]byte, expectedDataLength)
-	_, err = m.conn.Read(response)
+	_, err = conn.Read(response)
 
 	err = mbpayload.unMarshal(response)
 	if mbpayload.functionCode != 3 {