Implement fallback DNS resolution

This uses A / AAAA records while the preferred method in XMPP are SRV
records.

1 files changed, 30 insertions, 15 deletions

diff --git a/go/main.go b/go/main.go
index 8bfb1fa..4688055 100644
--- a/go/main.go
+++ b/go/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"image/color"
 	"log"
+	"net"
 	"os"
 
 	"gioui.org/app"
@@ -28,6 +29,7 @@ type Limox struct {
 	JidEditor  widget.Editor
 	PwdEditor  widget.Editor
 	MainButton widget.Clickable
+	XmppError  chan error
 	State      LimoxState
 	Window     *app.Window
 	Operations op.Ops
@@ -56,21 +58,26 @@ func NewLimox() Limox {
 		),
 		Operations: op.Ops{},
 		Theme:      material.NewTheme(gofont.Collection()),
+		XmppError:  make(chan error),
 		State:      Disconnected,
 	}
 }
 
 func (l *Limox) run() error {
 	for {
-		e := <-l.Window.Events()
-		switch e := e.(type) {
-		case system.DestroyEvent:
-			return e.Err
-		case system.FrameEvent:
-			if l.MainButton.Clicked() {
-				l.buttonCallback()
+		select {
+		case e := <-l.Window.Events():
+			switch e := e.(type) {
+			case system.DestroyEvent:
+				return e.Err
+			case system.FrameEvent:
+				if l.MainButton.Clicked() {
+					l.buttonCallback()
+				}
+				l.draw(e)
 			}
-			l.draw(e)
+		case <-l.XmppError:
+			l.State = Disconnected
 		}
 	}
 }
@@ -79,7 +86,7 @@ func (l *Limox) buttonCallback() {
 	switch l.State {
 	case Disconnected:
 		log.Println("Starting connection establishment")
-		go xmpp(l.JidEditor.Text(), l.PwdEditor.Text())
+		go l.xmpp(l.JidEditor.Text(), l.PwdEditor.Text())
 		l.State = Connecting
 	case Connecting:
 		log.Println("Aborted connection establishment")
@@ -90,9 +97,19 @@ func (l *Limox) buttonCallback() {
 	}
 }
 
-func xmpp(jid string, pwd string) {
+func (l *Limox) xmpp(jid string, pwd string) {
 	log.Printf("JID: '%s' PWD: '%s'\n", jid, pwd)
-	log.Printf("Domain: '%s'\n", domainpart(jid))
+
+	domain := domainpart(jid)
+	log.Printf("Domain: '%s'\n", domain)
+
+	tcpServer, err := net.ResolveTCPAddr("tcp", domain+":"+"5222")
+	if err != nil {
+		log.Print(err)
+		l.XmppError <- err
+		return
+	}
+	log.Printf("Server: %s\n", tcpServer)
 }
 
 // domainpart extracts the domain name from a JID / XMPP address. See
@@ -100,17 +117,15 @@ func xmpp(jid string, pwd string) {
 func domainpart(jid string) string {
 	list := []rune(jid)
 
-	for i, v := range(list) {
+	for i, v := range list {
 		if v == '/' {
-			log.Printf("Index of / rune: %d\n", i)
 			list = list[:i]
 			break
 		}
 	}
 
-	for i, v := range(list) {
+	for i, v := range list {
 		if v == '@' {
-			log.Printf("Index of @ rune: %d\n", i)
 			list = list[i+1:]
 			break
 		}