Reorder Auth and TLSClientHeaders middleware

This provides ForwardAuth the chance to inspect and make decisions based
on the TLS information.

server/server_middlewares.go

@@ -112,6 +112,15 @@ func (s *Server) buildMiddlewares(frontendName string, frontend *types.Frontend,
 		middle = append(middle, handler)
 	}
 
+	// TLSClientHeaders
+	tlsClientHeadersMiddleware := middlewares.NewTLSClientHeaders(frontend)
+	if tlsClientHeadersMiddleware != nil {
+		log.Debugf("Adding TLSClientHeaders middleware for frontend %s", frontendName)
+
+		handler := s.tracingMiddleware.NewNegroniHandlerWrapper("TLSClientHeaders", tlsClientHeadersMiddleware, false)
+		middle = append(middle, handler)
+	}
+
 	// Authentication
 	if frontend.Auth != nil {
 		authMiddleware, err := mauth.NewAuthenticator(frontend.Auth, s.tracingMiddleware)
@@ -123,15 +132,6 @@ func (s *Server) buildMiddlewares(frontendName string, frontend *types.Frontend,
 		middle = append(middle, handler)
 	}
 
-	// TLSClientHeaders
-	tlsClientHeadersMiddleware := middlewares.NewTLSClientHeaders(frontend)
-	if tlsClientHeadersMiddleware != nil {
-		log.Debugf("Adding TLSClientHeaders middleware for frontend %s", frontendName)
-
-		handler := s.tracingMiddleware.NewNegroniHandlerWrapper("TLSClientHeaders", tlsClientHeadersMiddleware, false)
-		middle = append(middle, handler)
-	}
-
 	return middle, buildModifyResponse(secureMiddleware, headerMiddleware), postConfig, nil
 }