espat: improve error handling for key TCP functions

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

espat/tcp.go

@@ -1,7 +1,9 @@
 package espat
 
 import (
+	"errors"
 	"strconv"
+	"strings"
 	"time"
 )
 
@@ -19,9 +21,12 @@ func (d *Device) ConnectTCPSocket(addr, port string) error {
 	protocol := "TCP"
 	val := "\"" + protocol + "\",\"" + addr + "\"," + port
 	d.Set(TCPConnect, val)
-	time.Sleep(pause * time.Millisecond)
+	time.Sleep(1000 * time.Millisecond)
-	d.Response()
+	r := d.Response()
-	return nil
+	if strings.Contains(string(r), "OK") {
+		return nil
+	}
+	return errors.New("ConnectTCPSocket error:" + string(r))
 }
 
 // ConnectUDPSocket creates a new UDP connection for the ESP8266/ESP32.
@@ -30,8 +35,11 @@ func (d *Device) ConnectUDPSocket(addr, sendport, listenport string) error {
 	val := "\"" + protocol + "\",\"" + addr + "\"," + sendport + "," + listenport + ",2"
 	d.Set(TCPConnect, val)
 	time.Sleep(pause * time.Millisecond)
-	d.Response()
+	r := d.Response()
-	return nil
+	if strings.Contains(string(r), "OK") {
+		return nil
+	}
+	return errors.New("ConnectUDPSocket error:" + string(r))
 }
 
 // DisconnectSocket disconnects the ESP8266/ESP32 from the current TCP/UDP connection.
@@ -78,17 +86,22 @@ func (d *Device) GetTCPTransferMode() []byte {
 func (d *Device) StartSocketSend(size int) error {
 	val := strconv.Itoa(size)
 	d.Set(TCPSend, val)
+	time.Sleep(pause * time.Millisecond)
 
-	// TODO: wait until ">" is received, which indicates
+	// when ">" is received, it indicates
 	// ready to receive data
-	d.Response()
+	r := d.Response()
-	return nil
+	if strings.Contains(string(r), ">") {
+		return nil
+	}
+	return errors.New("StartSocketSend error:" + string(r))
 }
 
 // EndSocketSend tell the ESP8266/ESP32 the TCP/UDP socket data sending is complete,
 // and to return to command mode. This is only used in "unvarnished" raw mode.
 func (d *Device) EndSocketSend() error {
 	d.Write([]byte("+++"))
+	time.Sleep(pause * time.Millisecond)
 
 	// TODO: wait until ">" is received, which indicates
 	// ready to receive data