Implement basic websocket connection

Author: matteosuppo

connect/connect.go

@@ -0,0 +1,85 @@
+// Package connect allows to open connections to devices connected to a serial port to
+// read and write from them
+//
+// Usage
+// 	ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
+// 	input, output, err := connect.Open(ctx, "/dev/ttyACM0", 9600)
+// 	if err != nil {
+// 		panic(err)
+// 	}
+// 	go func() {
+// 		for msg := range output {
+// 			fmt.Print(string(msg))
+// 		}
+// 	}()
+// 	input <- []byte("some message")
+package connect
+
+import (
+	"bytes"
+	"log"
+
+	"github.com/pkg/errors"
+
+	serial "go.bug.st/serial.v1"
+	"golang.org/x/net/context"
+)
+
+// Open will establish a connection to a device connected to a serial port
+// Will return two channels that will be used to communicate. Use input to send data,
+// read from output to retrieve data.
+// It accepts a cancelable context, so you can close the connection when you're finished
+// Errors during read or write will result in a the error being sent to the output channel
+// and the connection being closed
+func Open(ctx context.Context, name string, baud int) (input, output chan []byte, err error) {
+	mode := &serial.Mode{
+		BaudRate: baud,
+	}
+
+	p, err := serial.Open(name, mode)
+	if err != nil {
+		return nil, nil, errors.Wrapf(err, "open %s", name)
+	}
+
+	input = make(chan []byte)
+	output = make(chan []byte)
+
+	// reader
+	go func() {
+		for {
+			ch := make([]byte, 1024)
+			n, err := p.Read(ch)
+			if err != nil {
+				output <- []byte(err.Error())
+				break
+			}
+			if n > 0 {
+				log.Println(len(bytes.Trim(ch, "\x00")))
+				output <- bytes.Trim(ch, "\x00")
+			}
+		}
+
+		close(output)
+	}()
+
+	go func() {
+	L:
+		for {
+			select {
+			case <-ctx.Done():
+				break L
+			case msg := <-input:
+				_, err := p.Write(msg)
+				if err != nil {
+					output <- []byte(err.Error())
+					break L
+				}
+			}
+		}
+
+		p.Close()
+		close(input)
+	}()
+
+	return input, output, nil
+}

connect/connect_test.go

@@ -0,0 +1,29 @@
+package connect_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/arduino/arduino-create-agent/connect"
+	"golang.org/x/net/context"
+)
+
+func TestUsage(t *testing.T) {
+	ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
+
+	input, output, err := connect.Open(ctx, "/dev/ttyACM0", 9600)
+	if err != nil {
+		t.Fatalf(err.Error())
+	}
+
+	go func() {
+		for msg := range output {
+			fmt.Print(string(msg))
+		}
+	}()
+
+	input <- []byte("some message")
+
+	time.Sleep(11 * time.Second)
+}

connect_v1.go

@@ -1,38 +1,72 @@
 package main
 
 import (
+	"log"
+
 	"github.com/arduino/arduino-create-agent/app"
+	"github.com/arduino/arduino-create-agent/connect"
 	"github.com/goadesign/goa"
-	"golang.org/x/net/websocket"
-	"io"
+	"github.com/gorilla/websocket"
+	"golang.org/x/net/context"
 )
 
+type device struct {
+	input  chan []byte
+	output chan []byte
+	cancel func()
+}
+
 // ConnectV1Controller implements the connect_v1 resource.
 type ConnectV1Controller struct {
 	*goa.Controller
+	devices map[string]device
 }
 
 // NewConnectV1Controller creates a connect_v1 controller.
 func NewConnectV1Controller(service *goa.Service) *ConnectV1Controller {
-	return &ConnectV1Controller{Controller: service.NewController("ConnectV1Controller")}
+	return &ConnectV1Controller{
+		Controller: service.NewController("ConnectV1Controller"),
+		devices:    make(map[string]device),
+	}
 }
 
 // Websocket runs the websocket action.
 func (c *ConnectV1Controller) Websocket(ctx *app.WebsocketConnectV1Context) error {
-	c.WebsocketWSHandler(ctx).ServeHTTP(ctx.ResponseWriter, ctx.Request)
-	return nil
-}
+	cont, cancel := context.WithCancel(context.Background())
+	input, output, err := connect.Open(cont, ctx.Port, ctx.Baud)
+	if err != nil {
+		return ctx.BadRequest()
+	}
 
-// WebsocketWSHandler establishes a websocket connection to run the websocket action.
-func (c *ConnectV1Controller) WebsocketWSHandler(ctx *app.WebsocketConnectV1Context) websocket.Handler {
-	return func(ws *websocket.Conn) {
-		// ConnectV1Controller_Websocket: start_implement
+	var upgrader = websocket.Upgrader{
+		ReadBufferSize:  1024,
+		WriteBufferSize: 1024,
+	}
 
-		// Put your logic here
+	conn, err := upgrader.Upgrade(ctx.ResponseWriter, ctx.Request, nil)
+	if err != nil {
+		return ctx.BadRequest()
+	}
+
+	go func() {
+		for msg := range output {
+			log.Println(len(msg))
+
+			conn.WriteMessage(websocket.TextMessage, msg)
+		}
+		conn.Close()
+	}()
+
+	for {
+		_, msg, err := conn.ReadMessage()
+		if err != nil {
+			break
+		}
 
-		// ConnectV1Controller_Websocket: end_implement
-		ws.Write([]byte("websocket connect_v1"))
-		// Dummy echo websocket server
-		io.Copy(ws, ws)
+		input <- msg
 	}
+
+	cancel()
+
+	return nil
 }

templates/debug.html

@@ -85,6 +85,8 @@ <h1>Arduino Create Agent - Debug</h1>
 	});
 }
 
+var ws;
+
 function connect() {
 	var port = document.getElementById('connect-port').value;
 	var baud = document.getElementById('connect-baud').value;
@@ -93,7 +95,7 @@ <h1>Arduino Create Agent - Debug</h1>
 	var codeEl = document.getElementById('connect-code');
 
 	codeEl.textContent = '';
-	var ws = new WebSocket("ws://localhost:9000/v1/connect?port=" + port + "&baud=" + baud);
+	ws = new WebSocket("ws://localhost:9000/v1/connect?port=" + port + "&baud=" + baud);
 	ws.onopen = function () {
 		formEl.removeAttribute('hidden')
 	}
@@ -102,6 +104,7 @@ <h1>Arduino Create Agent - Debug</h1>
 		codeEl.textContent = codeEl.textContent + 'DISCONNECTED\n';
 	}
 	ws.onmessage = function (event) {
+		console.debug(event.data)
 		codeEl.textContent = codeEl.textContent + event.data + '\n';
 	}
 
@@ -116,5 +119,10 @@ <h1>Arduino Create Agent - Debug</h1>
 	console.debug(port, baud)
 }
 
+function send() {
+	var msg = document.getElementById('connect-msg').value;
+	ws.send(msg)
+}
+
 	</script>
 </body>