From b2b57d20e814e6c620ecc6e871cd8dfcaffffa98 Mon Sep 17 00:00:00 2001
From: "Christian R. Vozar" <christian@rogueethic.com>
Date: Wed, 10 Aug 2016 17:30:46 -0500
Subject: [PATCH] Pass Permanent Request Headers

---
 runtime/context.go      | 41 ++++++++++++++++++++++++++++++++++++++---
 runtime/context_test.go | 15 ++++++++-------
 2 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/runtime/context.go b/runtime/context.go
index ad42535662a..73a9da2fe24 100644
--- a/runtime/context.go
+++ b/runtime/context.go
@@ -15,7 +15,7 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
-const metadataHeaderPrefix = "Grpc-Metadata-"
+const metadataHeaderPrefix = "GrpcGateway-"
 const metadataTrailerPrefix = "Grpc-Trailer-"
 const metadataGrpcTimeout = "Grpc-Timeout"
 
@@ -48,8 +48,8 @@ func AnnotateContext(ctx context.Context, req *http.Request) (context.Context, e
 
 	for key, vals := range req.Header {
 		for _, val := range vals {
-			if key == "Authorization" {
-				pairs = append(pairs, "authorization", val)
+			if isPermanentHTTPHeader(key) {
+				pairs = append(pairs, strings.ToLower(fmt.Sprintf("%s%s", metadataHeaderPrefix, key)), val)
 				continue
 			}
 			if strings.HasPrefix(key, metadataHeaderPrefix) {
@@ -137,3 +137,38 @@ func timeoutUnitToDuration(u uint8) (d time.Duration, ok bool) {
 	}
 	return
 }
+
+// isPermanentHTTPHeader checks whether hdr belongs to the list of
+// permenant request headers maintained by IANA.
+// http://www.iana.org/assignments/message-headers/message-headers.xml
+func isPermanentHTTPHeader(hdr string) bool {
+	switch hdr {
+	case
+		"Accept",
+		"Accept-Charset",
+		"Accept-Language",
+		"Accept-Ranges",
+		"Authorization",
+		"Cache-Control",
+		"Content-Type",
+		"Cookie",
+		"Date",
+		"Expect",
+		"From",
+		"Host",
+		"If-Match",
+		"If-Modified-Since",
+		"If-None-Match",
+		"If-Schedule-Tag-Match",
+		"If-Unmodified-Since",
+		"Max-Forwards",
+		"Origin",
+		"Pragma",
+		"Referer",
+		"User-Agent",
+		"Via",
+		"Warning":
+		return true
+	}
+	return false
+}
diff --git a/runtime/context_test.go b/runtime/context_test.go
index abc1873fad9..9b30438b38a 100644
--- a/runtime/context_test.go
+++ b/runtime/context_test.go
@@ -1,6 +1,7 @@
 package runtime_test
 
 import (
+	"fmt"
 	"net/http"
 	"reflect"
 	"testing"
@@ -41,9 +42,9 @@ func TestAnnotateContext_ForwardsGrpcMetadata(t *testing.T) {
 		t.Fatalf("http.NewRequest(%q, %q, nil) failed with %v; want success", "GET", "http://www.example.com", err)
 	}
 	request.Header.Add("Some-Irrelevant-Header", "some value")
-	request.Header.Add("Grpc-Metadata-FooBar", "Value1")
-	request.Header.Add("Grpc-Metadata-Foo-BAZ", "Value2")
-	request.Header.Add("Grpc-Metadata-foo-bAz", "Value3")
+	request.Header.Add("GrpcGateway-FooBar", "Value1")
+	request.Header.Add("GrpcGateway-Foo-BAZ", "Value2")
+	request.Header.Add("GrpcGateway-foo-bAz", "Value3")
 	request.Header.Add("Authorization", "Token 1234567890")
 	annotated, err := runtime.AnnotateContext(ctx, request)
 	if err != nil {
@@ -52,16 +53,16 @@ func TestAnnotateContext_ForwardsGrpcMetadata(t *testing.T) {
 	}
 	md, ok := metadata.FromContext(annotated)
 	if got, want := len(md), emptyForwardMetaCount+3; !ok || got != want {
-		t.Errorf("Expected %d metadata items in context; got %d", got, want)
+		t.Errorf("Expected %d metadata items in context; got %d", got, want, md)
 	}
 	if got, want := md["foobar"], []string{"Value1"}; !reflect.DeepEqual(got, want) {
-		t.Errorf(`md["foobar"] = %q; want %q`, got, want)
+		t.Errorf(`md["GrpcGateway-foobar"] = %q; want %q`, got, want)
 	}
 	if got, want := md["foo-baz"], []string{"Value2", "Value3"}; !reflect.DeepEqual(got, want) {
-		t.Errorf(`md["foo-baz"] = %q want %q`, got, want)
+		t.Errorf(`md["GrpcGateway-foo-baz"] = %q want %q`, got, want)
 	}
 	if got, want := md["authorization"], []string{"Token 1234567890"}; !reflect.DeepEqual(got, want) {
-		t.Errorf(`md["authorization"] = %q want %q`, got, want)
+		t.Errorf(`md["GrpcGateway-authorization"] = %q want %q`, got, want)
 	}
 }