add JoinDefaultPort for servers' configuration

1 files changed, 17 insertions, 0 deletions

diff --git a/internal/server.go b/internal/server.go
index 3efdf6e..e3fbfb2 100644
--- a/internal/server.go
+++ b/internal/server.go
@@ -3,6 +3,7 @@ package internal
 import (
 	"context"
 	"net"
+	"strings"
 	"sync"
 )
 
@@ -126,3 +127,19 @@ func (s *Server) propagateClose() {
 		_ = s.Listener.Close()
 	}()
 }
+
+// JoinDefaultPort appends ":<port>" iff the address does not already contain a port.
+func JoinDefaultPort(address string, port string) string {
+	if address[0] == '[' {
+		hend := strings.LastIndexByte(address, ']')
+		if len(address) > hend+1 && address[hend+1] == ':' {
+			return address
+		}
+		return net.JoinHostPort(address[1:hend], port)
+	}
+
+	if strings.Contains(address, ":") {
+		return address
+	}
+	return net.JoinHostPort(address, port)
+}