Set window title by control message

app/app.go

@@ -1,19 +1,17 @@
 package app
 
 import (
-	"bytes"
 	"crypto/rand"
 	"encoding/base64"
-	htemplate "html/template"
+	"errors"
 	"log"
 	"math/big"
 	"net"
 	"net/http"
-	"os"
 	"os/exec"
 	"strconv"
 	"strings"
-	ttemplate "text/template"
+	"text/template"
 
 	"github.com/elazarl/go-bindata-assetfs"
 	"github.com/gorilla/websocket"
@@ -23,7 +21,8 @@ import (
 type App struct {
 	options Options
 
-	upgrader *websocket.Upgrader
+	upgrader      *websocket.Upgrader
+	titleTemplate *template.Template
 }
 
 type Options struct {
@@ -36,7 +35,12 @@ type Options struct {
 	Command     []string
 }
 
-func New(options Options) *App {
+func New(options Options) (*App, error) {
+	titleTemplate, err := template.New("title").Parse(options.TitleFormat)
+	if err != nil {
+		return nil, errors.New("Title format string syntax error")
+	}
+
 	return &App{
 		options: options,
 
@@ -45,7 +49,8 @@ func New(options Options) *App {
 			WriteBufferSize: 1024,
 			Subprotocols:    []string{"gotty"},
 		},
-	}
+		titleTemplate: titleTemplate,
+	}, nil
 }
 
 func (app *App) Run() error {
@@ -56,15 +61,13 @@ func (app *App) Run() error {
 
 	endpoint := app.options.Address + ":" + app.options.Port
 
-	indexHandler := http.HandlerFunc(app.handleIndex)
 	wsHandler := http.HandlerFunc(app.handleWS)
 	staticHandler := http.FileServer(
 		&assetfs.AssetFS{Asset: Asset, AssetDir: AssetDir, Prefix: "static"},
 	)
 
 	var siteMux = http.NewServeMux()
-	siteMux.Handle(path+"/", indexHandler)
-	siteMux.Handle(path+"/static/", http.StripPrefix(path+"/static/", staticHandler))
+	siteMux.Handle(path+"/", http.StripPrefix(path+"/", staticHandler))
 	siteMux.Handle(path+"/ws", wsHandler)
 
 	siteHandler := http.Handler(siteMux)
@@ -94,36 +97,6 @@ func (app *App) Run() error {
 	return nil
 }
 
-type TitleVars struct {
-	Command  string
-	Hostname string
-}
-
-type IndexVars struct {
-	Title string
-}
-
-func (app *App) handleIndex(w http.ResponseWriter, r *http.Request) {
-	title := make([]byte, 0)
-	titleBuf := bytes.NewBuffer(title)
-	hostname, _ := os.Hostname()
-	titleVars := TitleVars{
-		Command:  strings.Join(app.options.Command, " "),
-		Hostname: hostname,
-	}
-	titleTmpl, _ := ttemplate.New("title").Parse(app.options.TitleFormat)
-	titleTmpl.Execute(titleBuf, titleVars)
-
-	data, _ := Asset("templates/index.html")
-	tmpl, _ := htemplate.New("index").Parse(string(data))
-
-	vars := IndexVars{
-		Title: titleBuf.String(),
-	}
-
-	tmpl.Execute(w, vars)
-}
-
 func (app *App) handleWS(w http.ResponseWriter, r *http.Request) {
 	log.Printf("New client connected: %s", r.RemoteAddr)
 

app/client_context.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"os"
 	"os/exec"
+	"strings"
 	"syscall"
 	"unsafe"
 
@@ -26,11 +27,23 @@ const (
 	ResizeTerminal = '1'
 )
 
+const (
+	Output         = '0'
+	SetWindowTitle = '1'
+)
+
 type argResizeTerminal struct {
 	Columns float64
 	Rows    float64
 }
 
+type ContextVars struct {
+	Command    string
+	Pid        int
+	Hostname   string
+	RemoteAddr string
+}
+
 func (context *clientContext) goHandleClient() {
 	exit := make(chan bool, 2)
 
@@ -56,6 +69,11 @@ func (context *clientContext) goHandleClient() {
 }
 
 func (context *clientContext) processSend() {
+	if err := context.sendInitialize(); err != nil {
+		log.Printf(err.Error())
+		return
+	}
+
 	buf := make([]byte, 1024)
 	utf8f := utf8reader.New(context.pty)
 
@@ -71,11 +89,34 @@ func (context *clientContext) processSend() {
 			return
 		}
 
+		writer.Write([]byte{Output})
 		writer.Write(buf[:size])
 		writer.Close()
 	}
 }
 
+func (context *clientContext) sendInitialize() error {
+	hostname, _ := os.Hostname()
+	titleVars := ContextVars{
+		Command:    strings.Join(context.app.options.Command, " "),
+		Pid:        context.command.Process.Pid,
+		Hostname:   hostname,
+		RemoteAddr: context.request.RemoteAddr,
+	}
+
+	writer, err := context.connection.NextWriter(websocket.TextMessage)
+	if err != nil {
+		return err
+	}
+	writer.Write([]byte{SetWindowTitle})
+	if err = context.app.titleTemplate.Execute(writer, titleVars); err != nil {
+		return err
+	}
+	writer.Close()
+
+	return nil
+}
+
 func (context *clientContext) processReceive() {
 	for {
 		_, data, err := context.connection.ReadMessage()