To avoid duplicate response headers, only populate MultiValueHeaders (awslabs#73)

Author: jancona

core/response.go

@@ -103,15 +103,8 @@ func (r *ProxyResponseWriter) GetProxyResponse() (events.APIGatewayProxyResponse
 		isBase64 = true
 	}
 
-	proxyHeaders := make(map[string]string)
-
-	for h := range r.headers {
-		proxyHeaders[h] = r.headers.Get(h)
-	}
-
 	return events.APIGatewayProxyResponse{
 		StatusCode:        r.status,
-		Headers:           proxyHeaders,
 		MultiValueHeaders: http.Header(r.headers),
 		Body:              output,
 		IsBase64Encoded:   isBase64,

core/response_test.go

@@ -153,8 +153,8 @@ var _ = Describe("ResponseWriter tests", func() {
 			proxyResponse, err := response.GetProxyResponse()
 			Expect(err).To(BeNil())
 
-			// Headers are also written to `Headers` field
-			Expect(1).To(Equal(len(proxyResponse.Headers)))
+			// Headers are not also written to `Headers` field
+			Expect(0).To(Equal(len(proxyResponse.Headers)))
 			Expect(1).To(Equal(len(proxyResponse.MultiValueHeaders["Content-Type"])))
 			Expect("application/json").To(Equal(proxyResponse.MultiValueHeaders["Content-Type"][0]))
 		})
@@ -167,8 +167,8 @@ var _ = Describe("ResponseWriter tests", func() {
 			proxyResponse, err := response.GetProxyResponse()
 			Expect(err).To(BeNil())
 
-			// Headers are also written to `Headers` field
-			Expect(2).To(Equal(len(proxyResponse.Headers)))
+			// Headers are not also written to `Headers` field
+			Expect(0).To(Equal(len(proxyResponse.Headers)))
 
 			// There are two headers here because Content-Type is always written implicitly
 			Expect(2).To(Equal(len(proxyResponse.MultiValueHeaders["Set-Cookie"])))