refactor mappings getter

smtp/session.go

@@ -30,23 +30,18 @@ func (s *session) Mail(from string, opts smtp.MailOptions) error {
 
 func (s *session) Rcpt(to string) error {
 	sentry.GetHubFromContext(s.ctx).Scope().SetTag("to", to)
-	mappings, err := s.client.GetMappings(s.ctx)
-	if err != nil {
-		s.log.Error("cannot get mappings: %v", err)
-		return err
-	}
-	s.log.Debug("mappings: %v", mappings)
-	_, ok := mappings[utils.Mailbox(to)]
-	if !ok {
-		s.log.Debug("mapping for %s not found", to)
-		return smtp.ErrAuthRequired
-	}
 
 	if utils.Hostname(to) != s.domain {
 		s.log.Debug("wrong domain of %s", to)
 		return smtp.ErrAuthRequired
 	}
 
+	_, ok := s.client.GetMapping(s.ctx, utils.Mailbox(to))
+	if !ok {
+		s.log.Debug("mapping for %s not found", to)
+		return smtp.ErrAuthRequired
+	}
+
 	s.to = to
 	s.log.Debug("mail to %s", to)
 	return nil

smtp/smtp.go

@@ -9,6 +9,6 @@ import (
 
 // Client interface to send emails
 type Client interface {
-	GetMappings(context.Context) (map[string]id.RoomID, error)
+	GetMapping(context.Context, string) (id.RoomID, bool)
 	Send(ctx context.Context, from, mailbox, subject, body string, files []*utils.File) error
 }