Add body from basic auth plugin.

Fixes issue by adding unit test to make sure the body from
the plugin is written correctly and proxied to the client.

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

gateway/handlers/external_auth.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"context"
+	"io"
 	"net/http"
 	"time"
 )
@@ -36,5 +37,9 @@ func MakeExternalAuthHandler(next http.HandlerFunc, upstreamTimeout time.Duratio
 
 		copyHeaders(w.Header(), &res.Header)
 		w.WriteHeader(res.StatusCode)
+
+		if res.Body != nil {
+			io.Copy(w, res.Body)
+		}
 	}
 }

gateway/handlers/external_auth_test.go

@@ -1,6 +1,7 @@
 package handlers
 
 import (
+	"bytes"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -30,6 +31,36 @@ func Test_External_Auth_Wrapper_FailsInvalidAuth(t *testing.T) {
 	}
 }
 
+func Test_External_Auth_Wrapper_FailsInvalidAuth_WritesBody(t *testing.T) {
+
+	wantBody := []byte(`invalid credentials`)
+	s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusForbidden)
+		w.Write(wantBody)
+	}))
+
+	defer s.Close()
+
+	next := func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusNotImplemented)
+	}
+
+	passBody := false
+	handler := MakeExternalAuthHandler(next, time.Second*5, s.URL, passBody)
+
+	req := httptest.NewRequest(http.MethodGet, s.URL, nil)
+	rr := httptest.NewRecorder()
+	handler(rr, req)
+
+	if rr.Code == http.StatusOK {
+		t.Errorf("Status incorrect, did not want: %d, but got %d", http.StatusOK, rr.Code)
+	}
+
+	if bytes.Compare(rr.Body.Bytes(), wantBody) != 0 {
+		t.Errorf("Body incorrect, want: %s, but got %s", []byte(wantBody), rr.Body)
+	}
+}
+
 func Test_External_Auth_Wrapper_PassesValidAuth(t *testing.T) {
 
 	s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {