use postmoogle as general purpose SMTP server and allow other apps or scripts to send emails through it

bot/access.go

@@ -65,3 +65,18 @@ func (b *Bot) allowSend(actorID id.UserID, targetRoomID id.RoomID) bool {
 
 	return !cfg.NoSend()
 }
+
+// AllowAuth check if SMTP login (mailbox) and password are valid
+func (b *Bot) AllowAuth(mailbox, password string) bool {
+	roomID, ok := b.GetMapping(mailbox)
+	if !ok {
+		return false
+	}
+	cfg, err := b.getRoomSettings(roomID)
+	if err != nil {
+		b.log.Error("failed to retrieve settings: %v", err)
+		return false
+	}
+
+	return cfg.Password() != "" && cfg.Password() == password
+}

bot/command.go

@@ -73,6 +73,12 @@ func (b *Bot) initCommands() commandList {
 			sanitizer:   func(s string) string { return s },
 			allowed:     b.allowOwner,
 		},
+		{
+			key:         roomOptionPassword,
+			description: "Get or set SMTP password of the room's mailbox",
+			sanitizer:   func(s string) string { return strings.TrimSpace(s) },
+			allowed:     b.allowOwner,
+		},
 		{allowed: b.allowOwner}, // delimiter
 		{
 			key: roomOptionNoSend,
@@ -293,6 +299,11 @@ func (b *Bot) runSend(ctx context.Context) {
 		return
 	}
 
+	if !utils.AddressValid(to) {
+		b.Error(ctx, evt.RoomID, "email address is not valid")
+		return
+	}
+
 	cfg, err := b.getRoomSettings(evt.RoomID)
 	if err != nil {
 		b.Error(ctx, evt.RoomID, "failed to retrieve room settings: %v", err)

bot/email.go

@@ -46,8 +46,8 @@ func (b *Bot) GetMapping(mailbox string) (id.RoomID, bool) {
 }
 
 // Send email to matrix room
-func (b *Bot) Send2Matrix(ctx context.Context, email *utils.Email) error {
-	roomID, ok := b.GetMapping(utils.Mailbox(email.To))
+func (b *Bot) Send2Matrix(ctx context.Context, email *utils.Email, local bool) error {
+	roomID, ok := b.GetMapping(email.Mailbox(local))
 	if !ok {
 		return errors.New("room not found")
 	}
@@ -59,6 +59,10 @@ func (b *Bot) Send2Matrix(ctx context.Context, email *utils.Email) error {
 		b.Error(ctx, roomID, "cannot get settings: %v", err)
 	}
 
+	if !local && cfg.NoSend() {
+		return errors.New("that mailbox is receive-only")
+	}
+
 	var threadID id.EventID
 	if email.InReplyTo != "" && !cfg.NoThreads() {
 		threadID = b.getThreadID(roomID, email.InReplyTo)
@@ -81,6 +85,11 @@ func (b *Bot) Send2Matrix(ctx context.Context, email *utils.Email) error {
 	if !cfg.NoFiles() {
 		b.sendFiles(ctx, roomID, email.Files, cfg.NoThreads(), threadID)
 	}
+
+	if !local {
+		email.MessageID = fmt.Sprintf("<%s@%s>", eventID, b.domain)
+		return b.mta.Send(email.From, email.To, email.Compose(b.getBotSettings().DKIMPrivateKey()))
+	}
 	return nil
 }
 

bot/settings_room.go

@@ -21,6 +21,7 @@ const (
 	roomOptionNoHTML    = "nohtml"
 	roomOptionNoThreads = "nothreads"
 	roomOptionNoFiles   = "nofiles"
+	roomOptionPassword  = "password"
 )
 
 type roomSettings map[string]string
@@ -43,6 +44,10 @@ func (s roomSettings) Owner() string {
 	return s.Get(roomOptionOwner)
 }
 
+func (s roomSettings) Password() string {
+	return s.Get(roomOptionPassword)
+}
+
 func (s roomSettings) NoSend() bool {
 	return utils.Bool(s.Get(roomOptionNoSend))
 }