espat: add DialTLS and Dial methods, update MQTT example to allow both MQTT and MQTTS connections

Signed-off-by: Ron Evans <ron@hybridgroup.com>

espat/net.go

@@ -1,6 +1,7 @@
 package espat
 
 import (
+	"errors"
 	"strconv"
 	"strings"
 	"time"
@@ -54,6 +55,56 @@ func (d *Device) DialTCP(network string, laddr, raddr *TCPAddr) (*TCPSerialConn,
 	return &TCPSerialConn{SerialConn: SerialConn{Adaptor: d}, laddr: laddr, raddr: raddr}, nil
 }
 
+// Dial connects to the address on the named network.
+// It tries to provide a mostly compatible interface
+// to net.Dial().
+func (d *Device) Dial(network, address string) (Conn, error) {
+	switch network {
+	case "tcp":
+		raddr, err := d.ResolveTCPAddr(network, address)
+		if err != nil {
+			return nil, err
+		}
+
+		c, e := d.DialTCP(network, &TCPAddr{}, raddr)
+		return c.opConn(), e
+	case "udp":
+		raddr, err := d.ResolveUDPAddr(network, address)
+		if err != nil {
+			return nil, err
+		}
+
+		c, e := d.DialUDP(network, &UDPAddr{}, raddr)
+		return c.opConn(), e
+	default:
+		return nil, errors.New("invalid network for dial")
+	}
+}
+
+// DialTLS makes a TLS network connection. It tries to provide a mostly compatible interface
+// to tls.Dial().
+// DialTLS connects to the given network address.
+func (d *Device) DialTLS(network, address string, config *TLSConfig) (*TCPSerialConn, error) {
+	raddr, err := d.ResolveTCPAddr(network, address)
+	if err != nil {
+		return nil, err
+	}
+
+	addr := raddr.IP.String()
+	sendport := strconv.Itoa(raddr.Port)
+
+	// disconnect any old socket
+	d.DisconnectSocket()
+
+	// connect new socket
+	err = d.ConnectSSLSocket(addr, sendport)
+	if err != nil {
+		return nil, err
+	}
+
+	return &TCPSerialConn{SerialConn: SerialConn{Adaptor: d}, raddr: raddr}, nil
+}
+
 // SerialConn is a loosely net.Conn compatible implementation
 type SerialConn struct {
 	Adaptor *Device
@@ -103,23 +154,37 @@ func (c *SerialConn) Close() error {
 }
 
 // LocalAddr returns the local network address.
-func (c *UDPSerialConn) LocalAddr() UDPAddr {
-	return *c.laddr
+func (c *UDPSerialConn) LocalAddr() Addr {
+	return c.laddr.opAddr()
 }
 
 // RemoteAddr returns the remote network address.
-func (c *UDPSerialConn) RemoteAddr() UDPAddr {
-	return *c.laddr
+func (c *UDPSerialConn) RemoteAddr() Addr {
+	return c.laddr.opAddr()
+}
+
+func (c *UDPSerialConn) opConn() Conn {
+	if c == nil {
+		return nil
+	}
+	return c
 }
 
 // LocalAddr returns the local network address.
-func (c *TCPSerialConn) LocalAddr() TCPAddr {
-	return *c.laddr
+func (c *TCPSerialConn) LocalAddr() Addr {
+	return c.laddr.opAddr()
 }
 
 // RemoteAddr returns the remote network address.
-func (c *TCPSerialConn) RemoteAddr() TCPAddr {
-	return *c.laddr
+func (c *TCPSerialConn) RemoteAddr() Addr {
+	return c.laddr.opAddr()
+}
+
+func (c *TCPSerialConn) opConn() Conn {
+	if c == nil {
+		return nil
+	}
+	return c
 }
 
 // SetDeadline sets the read and write deadlines associated
@@ -217,6 +282,26 @@ type UDPAddr struct {
 	Zone string // IPv6 scoped addressing zone; added in Go 1.1
 }
 
+// Network returns the address's network name, "udp".
+func (a *UDPAddr) Network() string { return "udp" }
+
+func (a *UDPAddr) String() string {
+	if a == nil {
+		return "<nil>"
+	}
+	if a.Port != 0 {
+		return a.IP.String() + ":" + strconv.Itoa(a.Port)
+	}
+	return a.IP.String()
+}
+
+func (a *UDPAddr) opAddr() Addr {
+	if a == nil {
+		return nil
+	}
+	return a
+}
+
 // TCPAddr here to serve as compatible type. until TinyGo can compile the net package.
 type TCPAddr struct {
 	IP   IP
@@ -224,6 +309,26 @@ type TCPAddr struct {
 	Zone string // IPv6 scoped addressing zone
 }
 
+// Network returns the address's network name, "tcp".
+func (a *TCPAddr) Network() string { return "tcp" }
+
+func (a *TCPAddr) String() string {
+	if a == nil {
+		return "<nil>"
+	}
+	if a.Port != 0 {
+		return a.IP.String() + ":" + strconv.Itoa(a.Port)
+	}
+	return a.IP.String()
+}
+
+func (a *TCPAddr) opAddr() Addr {
+	if a == nil {
+		return nil
+	}
+	return a
+}
+
 // ParseIP parses s as an IP address, returning the result.
 func ParseIP(s string) IP {
 	return IP([]byte(s))
@@ -233,3 +338,67 @@ func ParseIP(s string) IP {
 func (ip IP) String() string {
 	return string(ip)
 }
+
+// TLSConfig is a placeholder for future compatibility with
+// tls.Config.
+type TLSConfig struct {
+}
+
+// Conn is a generic stream-oriented network connection.
+// This interface is from the Go standard library.
+type Conn interface {
+	// Read reads data from the connection.
+	// Read can be made to time out and return an Error with Timeout() == true
+	// after a fixed time limit; see SetDeadline and SetReadDeadline.
+	Read(b []byte) (n int, err error)
+
+	// Write writes data to the connection.
+	// Write can be made to time out and return an Error with Timeout() == true
+	// after a fixed time limit; see SetDeadline and SetWriteDeadline.
+	Write(b []byte) (n int, err error)
+
+	// Close closes the connection.
+	// Any blocked Read or Write operations will be unblocked and return errors.
+	Close() error
+
+	// LocalAddr returns the local network address.
+	LocalAddr() Addr
+
+	// RemoteAddr returns the remote network address.
+	RemoteAddr() Addr
+
+	// SetDeadline sets the read and write deadlines associated
+	// with the connection. It is equivalent to calling both
+	// SetReadDeadline and SetWriteDeadline.
+	//
+	// A deadline is an absolute time after which I/O operations
+	// fail with a timeout (see type Error) instead of
+	// blocking. The deadline applies to all future and pending
+	// I/O, not just the immediately following call to Read or
+	// Write. After a deadline has been exceeded, the connection
+	// can be refreshed by setting a deadline in the future.
+	//
+	// An idle timeout can be implemented by repeatedly extending
+	// the deadline after successful Read or Write calls.
+	//
+	// A zero value for t means I/O operations will not time out.
+	SetDeadline(t time.Time) error
+
+	// SetReadDeadline sets the deadline for future Read calls
+	// and any currently-blocked Read call.
+	// A zero value for t means Read will not time out.
+	SetReadDeadline(t time.Time) error
+
+	// SetWriteDeadline sets the deadline for future Write calls
+	// and any currently-blocked Write call.
+	// Even if write times out, it may return n > 0, indicating that
+	// some of the data was successfully written.
+	// A zero value for t means Write will not time out.
+	SetWriteDeadline(t time.Time) error
+}
+
+// Addr represents a network end point address.
+type Addr interface {
+	Network() string // name of the network (for example, "tcp", "udp")
+	String() string  // string form of address (for example, "192.0.2.1:25", "[2001:db8::1]:80")
+}

espat/tcp.go

@@ -54,6 +54,20 @@ func (d *Device) ConnectUDPSocket(addr, sendport, listenport string) error {
 	return errors.New("ConnectUDPSocket error:" + string(r))
 }
 
+// ConnectSSLSocket creates a new SSL socket connection for the ESP8266/ESP32.
+// Currently only supports single connection mode.
+func (d *Device) ConnectSSLSocket(addr, port string) error {
+	protocol := "SSL"
+	val := "\"" + protocol + "\",\"" + addr + "\"," + port + ",120"
+	d.Set(TCPConnect, val)
+	time.Sleep(5000 * time.Millisecond)
+	r := d.Response()
+	if strings.Contains(string(r), "CONNECT") {
+		return nil
+	}
+	return errors.New("ConnectSSLSocket error:" + string(r))
+}
+
 // DisconnectSocket disconnects the ESP8266/ESP32 from the current TCP/UDP connection.
 func (d *Device) DisconnectSocket() error {
 	d.Execute(TCPClose)

examples/espat/mqttclient/main.go

@@ -23,9 +23,11 @@ import (
 // access point info
 const ssid = "YOURSSID"
 const pass = "YOURPASS"
+const useSSL = true
 
 // IP address of the MQTT broker to use. Replace with your own info.
-const server = "test.mosquitto.org:1883"
+//const server = "test.mosquitto.org:1883"
+const server = "test.mosquitto.org:8883"
 
 // change these to connect to a different UART or pins for the ESP8266/ESP32
 var (
@@ -36,7 +38,7 @@ var (
 	console = machine.UART0
 
 	adaptor *espat.Device
-	conn    *espat.TCPSerialConn
+	conn    espat.Conn
 	err     error
 	mid     uint16
 	topic   = "tinygo"
@@ -64,20 +66,23 @@ func main() {
 		return
 	}
 
-	// now make TCP connection
-	raddr, _ := adaptor.ResolveTCPAddr("tcp", server)
-	if raddr != nil {
-		println("The IP address from DNS lookup is:")
-		println(string(raddr.IP))
-		println(raddr.Port)
-	}
-	laddr := &espat.TCPAddr{Port: 1883}
-
-	println("Dialing TCP connection...")
-	conn, err = adaptor.DialTCP("tcp", laddr, raddr)
-	if err != nil {
-		println("tcp connect error")
-		println(err.Error())
+	// make connection
+	if useSSL {
+		println("Dialing SSL connection...")
+		conn, err = adaptor.DialTLS("tcp", server, nil)
+		if err != nil {
+			println("SSL connect error")
+			println(err)
+			return
+		}
+	} else {
+		println("Dialing TCP connection...")
+		conn, err = adaptor.Dial("tcp", server)
+		if err != nil {
+			println("TCP connect error")
+			println(err)
+			return
+		}
 	}
 
 	err = connectToMQTTServer()