k8s.io/apiserver@v0.31.1/pkg/server/filters/hsts.go (about) 1 /* 2 Copyright 2020 The Kubernetes Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package filters 18 19 import ( 20 "net/http" 21 "strings" 22 ) 23 24 // WithHSTS is a simple HSTS implementation that wraps an http Handler. 25 // If hstsDirectives is empty or nil, no HSTS support is installed. 26 func WithHSTS(handler http.Handler, hstsDirectives []string) http.Handler { 27 if len(hstsDirectives) == 0 { 28 return handler 29 } 30 allDirectives := strings.Join(hstsDirectives, "; ") 31 return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) { 32 // Chrome and Mozilla Firefox maintain an HSTS preload list 33 // issue : golang.org/issue/26162 34 // Set the Strict-Transport-Security header if it is not already set 35 if _, ok := w.Header()["Strict-Transport-Security"]; !ok { 36 w.Header().Set("Strict-Transport-Security", allDirectives) 37 } 38 handler.ServeHTTP(w, req) 39 }) 40 }