fix http.Flusher and io.ReaderFrom implementation

http/interceptor.go

@@ -108,7 +108,23 @@ func (i *rwInterceptor) Header() http.Header {
 	return i.w.Header()
 }
 
-var _ http.ResponseWriter = (*rwInterceptor)(nil)
+func (i *rwInterceptor) ReadFrom(r io.Reader) (n int64, err error) {
+	return io.Copy(i, r)
+}
+
+func (i *rwInterceptor) Flush() {
+	if !i.wroteHeader {
+		i.WriteHeader(http.StatusOK)
+	}
+}
+
+type responseWriter interface {
+	http.ResponseWriter
+	io.ReaderFrom
+	http.Flusher
+}
+
+var _ responseWriter = (*rwInterceptor)(nil)
 
 // wrap wraps the interceptor into a response writer that also preserves
 // the http interfaces implemented by the original response writer to avoid
@@ -168,110 +184,28 @@ func wrap(w http.ResponseWriter, r *http.Request, tx types.Transaction) (
 	var (
 		hijacker, isHijacker = i.w.(http.Hijacker)
 		pusher, isPusher     = i.w.(http.Pusher)
-		flusher, isFlusher   = i.w.(http.Flusher)
-		reader, isReader     = i.w.(io.ReaderFrom)
 	)
 
 	switch {
-	case !isHijacker && !isPusher && !isFlusher && !isReader:
+	case !isHijacker && isPusher:
 		return struct {
-			http.ResponseWriter
-		}{i}, responseProcessor
-	case !isHijacker && !isPusher && !isFlusher && isReader:
-		return struct {
-			http.ResponseWriter
-			io.ReaderFrom
-		}{i, reader}, responseProcessor
-	case !isHijacker && !isPusher && isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
-			http.Flusher
-		}{i, flusher}, responseProcessor
-	case !isHijacker && !isPusher && isFlusher && isReader:
-		return struct {
-			http.ResponseWriter
-			http.Flusher
-			io.ReaderFrom
-		}{i, flusher, reader}, responseProcessor
-	case !isHijacker && isPusher && !isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
+			responseWriter
 			http.Pusher
 		}{i, pusher}, responseProcessor
-	case !isHijacker && isPusher && !isFlusher && isReader:
-		return struct {
-			http.ResponseWriter
-			http.Pusher
-			io.ReaderFrom
-		}{i, pusher, reader}, responseProcessor
-	case !isHijacker && isPusher && isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
-			http.Pusher
-			http.Flusher
-		}{i, pusher, flusher}, responseProcessor
-	case !isHijacker && isPusher && isFlusher && isReader:
+	case isHijacker && !isPusher:
 		return struct {
-			http.ResponseWriter
-			http.Pusher
-			http.Flusher
-			io.ReaderFrom
-		}{i, pusher, flusher, reader}, responseProcessor
-	case isHijacker && !isPusher && !isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
+			responseWriter
 			http.Hijacker
 		}{i, hijacker}, responseProcessor
-	case isHijacker && !isPusher && !isFlusher && isReader:
+	case isHijacker && isPusher:
 		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			io.ReaderFrom
-		}{i, hijacker, reader}, responseProcessor
-	case isHijacker && !isPusher && isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Flusher
-		}{i, hijacker, flusher}, responseProcessor
-	case isHijacker && !isPusher && isFlusher && isReader:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Flusher
-			io.ReaderFrom
-		}{i, hijacker, flusher, reader}, responseProcessor
-	case isHijacker && isPusher && !isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
+			responseWriter
 			http.Hijacker
 			http.Pusher
 		}{i, hijacker, pusher}, responseProcessor
-	case isHijacker && isPusher && !isFlusher && isReader:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-			io.ReaderFrom
-		}{i, hijacker, pusher, reader}, responseProcessor
-	case isHijacker && isPusher && isFlusher && !isReader:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-			http.Flusher
-		}{i, hijacker, pusher, flusher}, responseProcessor
-	case isHijacker && isPusher && isFlusher && isReader:
-		return struct {
-			http.ResponseWriter
-			http.Hijacker
-			http.Pusher
-			http.Flusher
-			io.ReaderFrom
-		}{i, hijacker, pusher, flusher, reader}, responseProcessor
 	default:
 		return struct {
-			http.ResponseWriter
+			responseWriter
 		}{i}, responseProcessor
 	}
 }