runtime: fix chunk encoding

Author: emcfarlane

runtime/handler.go

@@ -58,7 +58,7 @@ func ForwardResponseStream(ctx context.Context, mux *ServeMux, marshaler Marshal
 			grpclog.Printf("Failed to marshal response chunk: %v", err)
 			return
 		}
-		if _, err = fmt.Fprintf(w, "%s\n", buf); err != nil {
+		if _, err = w.Write(buf); err != nil {
 			grpclog.Printf("Failed to send response chunk: %v", err)
 			return
 		}

runtime/handler_test.go

@@ -0,0 +1,67 @@
+package runtime_test
+
+import (
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/golang/protobuf/proto"
+	pb "github.com/grpc-ecosystem/grpc-gateway/examples/examplepb"
+	"github.com/grpc-ecosystem/grpc-gateway/runtime"
+	"golang.org/x/net/context"
+)
+
+func TestForwardResponseStream(t *testing.T) {
+	var (
+		msgs = []proto.Message{
+			&pb.SimpleMessage{Id: "One"},
+			&pb.SimpleMessage{Id: "Two"},
+		}
+
+		ctx = runtime.NewServerMetadataContext(
+			context.Background(), runtime.ServerMetadata{},
+		)
+		mux       = runtime.NewServeMux()
+		marshaler = &runtime.JSONPb{}
+		req       = httptest.NewRequest("GET", "http://example.com/foo", nil)
+		resp      = httptest.NewRecorder()
+		count     = 0
+		recv      = func() (proto.Message, error) {
+			if count >= len(msgs) {
+				return nil, io.EOF
+			}
+			count++
+			return msgs[count-1], nil
+		}
+	)
+
+	runtime.ForwardResponseStream(ctx, mux, marshaler, resp, req, recv)
+
+	w := resp.Result()
+	if w.StatusCode != http.StatusOK {
+		t.Errorf(" got %d want %d", w.StatusCode, http.StatusOK)
+	}
+	if h := w.Header.Get("Transfer-Encoding"); h != "chunked" {
+		t.Errorf("ForwardResponseStream missing header chunked")
+	}
+	body, err := ioutil.ReadAll(w.Body)
+	if err != nil {
+		t.Errorf("Failed to read response body with %v", err)
+	}
+	w.Body.Close()
+
+	var want []byte
+	for _, msg := range msgs {
+		b, err := marshaler.Marshal(map[string]proto.Message{"result": msg})
+		if err != nil {
+			t.Errorf("marshaler.Marshal() failed %v", err)
+		}
+		want = append(want, b...)
+	}
+
+	if string(body) != string(want) {
+		t.Errorf("ForwardResponseStream() = \"%s\" want \"%s\"", body, want)
+	}
+}