--- parser: v2 author_name: Thomas Jung author_profile: https://github.com/jung-thomas primary_tag: products>sap-hana tags: [ tutorial>intermediate, products>sap-hana, products>sap-hana\,-express-edition ] time: 15 slug: xsa-node-websockets canonical_url: https://developers.sap.com/tutorials/xsa-node-websockets --- # SAP HANA XS Advanced - Web Sockets within Node.js SAP HANA applications Using web sockets with Node.js and SAP HANA ## Prerequisites - This tutorial is designed for SAP HANA on premise and SAP HANA, express edition. It is not designed for SAP HANA Cloud. - **Tutorials:** [Text Bundles](https://developers.sap.com/tutorials/xsa-node-text.html) ## You will learn This section will demonstrate the ease at which you can tap into the powerful web sockets capabilities of Node.js You will use web sockets to build a simple chat application. Any message sent from the SAPUI5 client side application will be propagated by the server to all listening clients. --- ### Require new module Add an express route handler for this `chatServer` module and pass the server variable in as well. ```JavaScript /*eslint no-console: 0, no-unused-vars: 0, no-undef:0, no-process-exit:0*/ /*eslint-env node, es6 */ "use strict"; module.exports = (app, server) => { app.use("/node", require("./routes/myNode")()); app.use("/node/excAsync", require("./routes/exerciseAsync")(server)); app.use("/node/textBundle", require("./routes/textBundle")()); app.use("/node/chat", require("./routes/chatServer")(server)); app.use( (err, req, res, next) => { console.error(JSON.stringify(err)); res.status(500).send(`System Error ${JSON.stringify(err)}`); }); }; ``` ### Add route handler Create a file called `chatServer.js` inside your `routes` folder with the following code: ```JavaScript /*eslint no-console: 0, no-unused-vars: 0, new-cap: 0*/ /*eslint-env node, es6 */ "use strict"; var WebSocketServer = require("ws").Server; var express = require("express"); module.exports = function (server) { var app = express.Router(); app.use((req, res) => { var output = `

Node.js Web Socket Examples


/exerciseChat - Chat Application for Web Socket Example
`; res.type("text/html").status(200).send(output); }); var wss = new WebSocketServer({ // server: server, noServer: true, path: "/node/chatServer" }); server.on("upgrade", function upgrade(request, socket, head) { const url = require("url"); const pathname = url.parse(request.url).pathname; if (pathname === "/node/chatServer") { wss.handleUpgrade(request, socket, head, function done(ws) { wss.emit("connection", ws, request); }); } }); wss.broadcast = (data) => { wss.clients.forEach(function each(client) { try { client.send(data); } catch (e) { console.log("Broadcast Error: %s", e.toString()); } }); console.log("sent: %s", data); }; wss.on("connection", (ws) => { console.log("Connected"); ws.on("message", (message) => { console.log("received: %s", message); wss.broadcast(message); }); ws.send(JSON.stringify({ user: "XS", text: "Hello from Node.js XS Server" })); }); return app; }; ``` >Note: You can find more information on the `WebSockets` module and how it works the their [GitHub repository](https://github.com/websockets/ws) ### Create a UI5 interface The file structure for this interface will be simple as it is not the focus for this tutorial. Create a folder called `exerciseChat` in your web module, in `resources`: ![folder](https://raw.githubusercontent.com/sap-tutorials/Tutorials/master/tutorials/xsa-node-websockets/3.png) Create a folder called `view` within that folder. It will contain one file, with the following name and code: `view/App.view.xml` ```XML