Inital Working Dummy for basic Serial Communication

MessageHandler/handler.go

@@ -0,0 +1,139 @@
+package MessageHandler
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/gorilla/websocket"
+)
+
+type SerialInteraction interface {
+	ListComports() []string
+	Connect(string) error
+	Disconnect()
+	Write([]byte) (int, error)
+	Read([]byte) (int, error)
+	GetPortPath() string
+}
+
+type MessageHandler struct {
+	Serial     SerialInteraction
+	socket     *websocket.Conn
+	socketLock sync.Mutex
+}
+
+const (
+	VERSION = "1"
+)
+
+func (mh *MessageHandler) WebsocketHandle(w http.ResponseWriter, r *http.Request, c *websocket.Conn) {
+	for {
+		mt, message, err := c.ReadMessage()
+		if err != nil {
+			log.Printf("read: %v", err)
+			break
+		}
+		log.Printf("recv: %s", message)
+		answer := mh.messageDispatcher(string(message))
+		mh.socketLock.Lock()
+		err = c.WriteMessage(mt, []byte(answer))
+		mh.socketLock.Unlock()
+		if err != nil {
+			log.Printf("write: %v", err)
+			break
+		}
+	}
+}
+
+// message format, ";" seperated message version;command;argc;args....?
+func (mh *MessageHandler) messageDispatcher(message string) string {
+	messageParts := strings.Split(message, ";")
+
+	if len(messageParts) < 3 {
+		log.Printf("Message to Short, %v", message)
+		return ""
+	}
+
+	switch messageParts[0] {
+	case VERSION:
+		break
+	default:
+		log.Printf("Unknow Version %v in Message %v", messageParts[0], message)
+		return ""
+	}
+
+	switch messageParts[1] {
+	case "listports":
+		return mh.ListComports()
+	case "connect":
+		return mh.Connect(messageParts[4])
+	case "disconnect":
+		return mh.Disconnect()
+	case "write":
+		return mh.Write(messageParts[4])
+	case "read":
+		return mh.Read()
+	default:
+		log.Printf("unknow command %v", message)
+		break
+	}
+	return ""
+}
+
+func (mh *MessageHandler) ListComports() string {
+	ports := mh.Serial.ListComports()
+	message := MessageBuilder("portlist", ports...)
+	return message
+}
+
+func (mh *MessageHandler) Connect(portname string) string {
+	err := mh.Serial.Connect(portname)
+	message := ""
+	if err != nil {
+		message = MessageBuilder("error", "connection")
+	} else {
+		message = MessageBuilder("connected", "portname")
+	}
+	return message
+}
+
+func (mh *MessageHandler) Disconnect() string {
+	mh.Serial.Disconnect()
+	return MessageBuilder("disconnected")
+}
+
+func (mh *MessageHandler) Write(msg string) string {
+	_, err := mh.Serial.Write([]byte(msg))
+	if err != nil {
+		return MessageBuilder("write", fmt.Sprintf("write error %v", err))
+	}
+	return MessageBuilder("write")
+}
+
+func (mh *MessageHandler) Read() string {
+	buffer := make([]byte, 1024)
+	_, err := mh.Serial.Read(buffer)
+	if err != nil {
+		return MessageBuilder("read", fmt.Sprintf("read error %v", err))
+	}
+	return MessageBuilder("read", string(buffer))
+}
+
+// version;command;argc;argv;
+// recv: 1;connect;1;/dev/ttyUSB0;
+// send: 1;connected;0;		// no args can be used as a acc command
+// send: 1;connected;1;error: port not found;
+// recv: 1;discoonect;0;
+// send: 1;discoonect;0;
+// recv: 1;write;1;viele viele bunte bytes;
+// send: 1;write;0;
+// send: 1;write;1;error: port not connected;
+// send: 1:read:1;das hab ich gelesen junge;
+
+func MessageBuilder(command string, args ...string) string {
+	return VERSION + ";" + command + ";" + strconv.Itoa(len(args)) + ";" + strings.Join(args, ";")
+}