diff --git a/src/util.js b/src/util.js
index 37d0f11..b97ae4c 100644
--- a/src/util.js
+++ b/src/util.js
@@ -9,7 +9,13 @@ module.exports = function(req, body, url, res) {
 
 	/* N parameter specifies worksheet index */
 	const N = url.query.N ? parseInt(url.query.N,10) : 0;
+	
+	const addr = url.query.addr || null;
+	const val = url.query.val || null;
 
+	if (addr != null && val != null) {
+		XLSX.utils.sheet_add_aoa(wb.Sheets[wb.SheetNames[0]], [[val]], { origin: addr });
+	}
 	/* -1 -> return sheet names */
 	if(N < 0) switch(url.query.t || "csv") {
 		case "json": return res.status(200).send(JSON.stringify(wb.SheetNames.join("\n")));
@@ -28,6 +34,11 @@ module.exports = function(req, body, url, res) {
 	switch(url.query.t) {
 		case "json": return res.status(200).json(XLSX.utils.sheet_to_json(ws, {header:1, raw:true}));
 		case "html": return XLSX.stream.to_html(ws).pipe(res);
+		case "file": 
+			const buf = XLSX.write(wb, { type: "buffer", bookType: "xlsx" });
+			res.header("Content-Type", "application/vnd.ms-excel");
+			res.header("Content-Disposition", 'attachment; filename="test2.xlsx"');
+			return res.status(200).end(buf);	
 		default: return XLSX.stream.to_csv(ws).pipe(res);
 	}
 };