core/corehttp: Added cache headers to gatewayy requests

core/corehttp/gateway_handler.go

@@ -130,6 +130,8 @@ func (i *gatewayHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("X-IPFS-Path", p)
+	w.Header().Set("Etag", path.Base(p))
+	w.Header().Set("Cache-Control", "public, max-age=29030400")
 
 	dr, err := i.NewDagReader(nd)
 	if err == nil {