Add local web server to serve the app

cmd/txqr-tester/.gitignore

@@ -0,0 +1 @@
+txqr-tester

cmd/txqr-tester/app/main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"github.com/gopherjs/vecty"
+)
+
+func main() {
+	app := NewApp()
+
+	vecty.SetTitle("TXQR Automated Tester")
+	vecty.AddStylesheet("css/bulma.css")
+	vecty.AddStylesheet("css/bulma-extensions.min.css")
+	vecty.AddStylesheet("css/custom.css")
+	vecty.RenderBody(app)
+}

cmd/txqr-tester/ip.go

@@ -0,0 +1,20 @@
+package main
+
+import "net"
+
+// GetLocalIP returns the non loopback local IP of the host.
+func GetLocalIP() string {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return ""
+	}
+	for _, address := range addrs {
+		// check the address type and if it is not a loopback the display it
+		if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
+			if ipnet.IP.To4() != nil {
+				return ipnet.IP.String()
+			}
+		}
+	}
+	return ""
+}

cmd/txqr-tester/main.go

@@ -1,15 +1,14 @@
 package main
 
 import (
-	"github.com/gopherjs/vecty"
+	"flag"
+	"log"
 )
 
 func main() {
-	app := NewApp()
+	flag.Parse()
 
-	vecty.SetTitle("TXQR Automated Tester")
-	vecty.AddStylesheet("css/bulma.css")
-	vecty.AddStylesheet("css/bulma-extensions.min.css")
-	vecty.AddStylesheet("css/custom.css")
-	vecty.RenderBody(app)
+	if err := StartApp(":1999"); err != nil {
+		log.Fatalf("[ERROR] Can't start web server to serve the app")
+	}
 }

cmd/txqr-tester/web.go

@@ -0,0 +1,67 @@
+//go:generate go-bindata-assetfs app/index.html app/css/... app/txqr-tester.js
+package main
+
+import (
+	"fmt"
+	"html/template"
+	"net/http"
+	"os"
+	"os/exec"
+	"runtime"
+)
+
+type PageInfo struct {
+	Title string
+}
+
+// indexTmpl is a html template for index page.
+var (
+	indexTmpl *template.Template
+)
+
+func init() {
+	data, err := Asset("app/index.html")
+	if err != nil {
+		panic(err)
+	}
+	indexTmpl = template.Must(template.New("index.html").Parse(string(data)))
+}
+
+// StartApp generates app page, serves it via http
+// and tries to open it using default browser.
+func StartApp(bind string) error {
+	http.Handle("/", http.FileServer(assetFS()))
+	go StartBrowser("http://localhost" + bind)
+
+	return http.ListenAndServe(bind, nil)
+}
+
+// handler handles index page.
+func handler(w http.ResponseWriter, r *http.Request, info *PageInfo) {
+	err := indexTmpl.Execute(w, info)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprintln(os.Stderr, "[ERROR] Failed to render template:", err)
+		return
+	}
+}
+
+// StartBrowser tries to open the URL in a browser
+// and reports whether it succeeds.
+//
+// Orig. code: golang.org/x/tools/cmd/cover/html.go
+func StartBrowser(url string) bool {
+	// try to start the browser
+	var args []string
+	switch runtime.GOOS {
+	case "darwin":
+		args = []string{"open"}
+	case "windows":
+		args = []string{"cmd", "/c", "start"}
+	default:
+		args = []string{"xdg-open"}
+	}
+	cmd := exec.Command(args[0], append(args[1:], url)...)
+	fmt.Println("If browser window didn't appear, please go to this url:", url)
+	return cmd.Start() == nil
+}