templates: Parse host successfully when port is implicit (fixes #292)

middleware/context.go

@@ -97,6 +97,10 @@ func (c Context) URI() string {
 func (c Context) Host() (string, error) {
 	host, _, err := net.SplitHostPort(c.Req.Host)
 	if err != nil {
+		if !strings.Contains(c.Req.Host, ":") {
+			// common with sites served on the default port 80
+			return c.Req.Host, nil
+		}
 		return "", err
 	}
 	return host, nil