Merge pull request #9 from JSainsburyPLC/feature/proxy-response-headers

proxy response headers

Author: webbgeorge

README.md

@@ -50,6 +50,9 @@ See `examples/config.json`
   }],
   "proxy_pass_headers": { // additional proxy headers. Optional
     "Referer": "https://www.test.example.com"
+  },
+  "proxy_response_headers": { // set response headers. Optional
+    "Cache-Control": "no-cache"
   }
 }
 ```

domain/config.go

@@ -17,13 +17,14 @@ type Config struct {
 }
 
 type Route struct {
-	Type             string            `json:"type"`
-	PathPattern      *PathPattern      `json:"path_pattern"`
-	Backend          *Backend          `json:"backend"`
-	Mock             *Mock             `json:"mock"`
-	Rewrite          []Rewrite         `json:"rewrite"`
-	Redirect         *Redirect         `json:"redirect"`
-	ProxyPassHeaders map[string]string `json:"proxy_pass_headers"`
+	Type                 string            `json:"type"`
+	PathPattern          *PathPattern      `json:"path_pattern"`
+	Backend              *Backend          `json:"backend"`
+	Mock                 *Mock             `json:"mock"`
+	Rewrite              []Rewrite         `json:"rewrite"`
+	Redirect             *Redirect         `json:"redirect"`
+	ProxyPassHeaders     map[string]string `json:"proxy_pass_headers"`
+	ProxyResponseHeaders map[string]string `json:"proxy_response_headers"`
 }
 
 type Rewrite struct {

examples/config.json

@@ -36,6 +36,9 @@
       }],
       "proxy_pass_headers": {
         "Referer": "https://www.test1.example.co.uk/"
+      },
+      "proxy_response_headers": {
+        "Cache-Control": "no-cache"
       }
     },
     {

go.mod

@@ -3,7 +3,7 @@ module github.com/JSainsburyPLC/ui-dev-proxy
 go 1.13
 
 require (
-	github.com/steinfletcher/apitest v1.3.13
-	github.com/stretchr/testify v1.4.0
+	github.com/steinfletcher/apitest v1.4.4
+	github.com/stretchr/testify v1.5.1
 	github.com/urfave/cli v1.22.1
 )

go.sum

@@ -11,9 +11,13 @@ github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5I
 github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/steinfletcher/apitest v1.3.13 h1:E0BAXde9dke8jEjK1hqTGvmI20vyyfC+xSdE9nmTc84=
 github.com/steinfletcher/apitest v1.3.13/go.mod h1:pCHKMM2TcH1pezw/xbmilaCdK9/dGsoCZBafwaqJ2sY=
+github.com/steinfletcher/apitest v1.4.4 h1:ZT/Wa3J615x7mBuarTf92o43AseYfHEFsLhnl1dBkl4=
+github.com/steinfletcher/apitest v1.4.4/go.mod h1:yaYc9GDlj4fa0qUUDywqAmrELlNbDrBwd36Zgo5hMZo=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
+github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/urfave/cli v1.22.1 h1:+mkCCcOFKPnCmVYVcURKps1Xe+3zP90gSYGNfRkjoIY=
 github.com/urfave/cli v1.22.1/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

proxy/proxy.go

@@ -32,8 +32,9 @@ func NewProxy(
 	logger *log.Logger,
 ) *Proxy {
 	reverseProxy := &httputil.ReverseProxy{
-		Director:     director(defaultBackend, logger),
-		ErrorHandler: errorHandler(logger),
+		Director:       director(defaultBackend, logger),
+		ModifyResponse: modifyResponse(),
+		ErrorHandler:   errorHandler(logger),
 	}
 	return &Proxy{
 		server: &http.Server{
@@ -92,6 +93,22 @@ func director(defaultBackend *url.URL, logger *log.Logger) func(req *http.Reques
 	}
 }
 
+func modifyResponse() func(*http.Response) error {
+	return func(res *http.Response) error {
+		route, ok := res.Request.Context().Value(routeCtxKey).(*domain.Route)
+		if !ok {
+			// if route not set, then default backend was used and no route match config available
+			return nil
+		}
+
+		for k, v := range route.ProxyResponseHeaders {
+			res.Header.Set(k, v)
+		}
+
+		return nil
+	}
+}
+
 func errorHandler(logger *log.Logger) func(http.ResponseWriter, *http.Request, error) {
 	return func(w http.ResponseWriter, r *http.Request, err error) {
 		logger.Printf("%+v\n", err)
@@ -135,6 +152,7 @@ func handler(
 				logger.Printf(err.Error())
 				w.WriteHeader(http.StatusBadGateway)
 				_, _ = w.Write([]byte("Bad gateway"))
+				return
 			}
 
 			http.Redirect(w, r, u.String(), redirectStatusCode(matchedRoute.Redirect.Type))

proxy/proxy_test.go

@@ -58,6 +58,7 @@ func TestProxy_ProxyBackend_UserProxy_Success(t *testing.T) {
 		Get("/test-ui/users/info").
 		Expect(t).
 		Status(http.StatusOK).
+		Header("Cache-Control", "no-cache").
 		Body(`{"user_id": "123"}`).
 		End()
 }
@@ -271,6 +272,9 @@ func config() domain.Config {
 				ProxyPassHeaders: map[string]string{
 					"Referer": "https://www.test.example.com",
 				},
+				ProxyResponseHeaders: map[string]string{
+					"Cache-Control": "no-cache",
+				},
 			},
 			{
 				Type:        "proxy",