How to set X-Frame-Options in express.js node.js

Question

I have some static assets that I want to serve inside iframes of several desktop / mobile web clients.

Now, how do I whitelist a specific set of origins to be allowed setting of X-Frame-Options headers so that the resource can be embedded as iframes inside different desktop / mobile web clients. and for all other origins denies the access to this resource.

With a little digging I started off with -

const app = express();

var allowCrossDomain = function (req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
    res.header('Access-Control-Allow-Headers', 'Content-Type, X-Requested-With, Authorization');
    if (req.method === "OPTIONS") res.send(200);
    else next();
}
app.use(allowCrossDomain);

Now here how do I set the X-Frame-Options header with the whitelisted origin values here -

Answer 1

You should import helmet and use frameguard to get some origins whitelisted. More on this topic: MDN X-FRAME-OPTIONS Best Practice Security

Answer 2

all you need is helmet

npm install helmet --save 

const express = require('express')
const helmet = require('helmet')

const app = express()

app.use(helmet.frameguard())