Dust.js and helmet - not rendering HTML - stream

Question

I have a Dust.js template and want to use it as async mode (so stream), to load my stuff.
It works very well, but when I add use(helmet()) it does not show as html anymore, just as plain text
I tried using dust.stream, tried hoffman, tried adaro. nothing works, the second helmet is introduced, it does not work.
hoffman
hoffman = require('hoffman'),
express = require('express'),
helmet = require('helmet'),
request = require('request');
var app = express();
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'dust');
app.engine('dust', hoffman.__express());
app.use(helmet());
// This is the important part-- it adds res.stream()
app.use(hoffman.stream);
app.get('/', function (req, res) {
res.stream("hello", {
"async": function(chunk, context, bodies, params) {
return chunk.map(function(chunk) {
// Introducting an artificial delay to make streaming more apparent
setTimeout(function() {
request('http://www.dustjs.com/')
.on('data', chunk.write.bind(chunk))
.on('end', chunk.end.bind(chunk));
}, 3000);
});
}
});
});
const port = process.env.PORT | 3007;
app.listen(port, function () {
console.log(`Visit http://localhost:${port} to see streaming!`);
});
Dust.stream:
var fs = require('fs'),
path = require('path'),
express = require('express'),
request = require('request'),
helmet = require('helmet'),
dust = require('dustjs-linkedin');
dust.config.whitespace = true;
dust.config.cache = false;
// Define a custom `onLoad` function to tell Dust how to load templates
dust.onLoad = function(tmpl, cb) {
fs.readFile(path.join('./views', path.relative('/', path.resolve('/', tmpl + '.dust'))),
{ encoding: 'utf8' }, cb);
};
var app = express();
app.use(helmet());
app.get('/streaming', function(req, res) {
dust.stream('hello', {
"async": request('http://www.dustjs.com/')
}).pipe(res)
.on('end', function() {
console.log('Done streaming!');
});
});
app.get('/rendering', function(req, res) {
dust.render('hello', {
"async": request('http://www.dustjs.com/')
}, function(err, out) {
res.send(out);
console.log('Done rendering!');
});
});
const port = process.env.PORT | 3002;
app.listen(port, function () {
console.log(`Visit http://localhost:${port} to see streaming!`);
});
When not using helmet, the html is rendered, when adding helmet, no rendering is done, and I see the html page as text

Answer 1

Ok, so dust does a nice job with async.
The bit I was missing was:
res.setHeader('Content-Type', 'text/html; charset=utf-8');
and now it works with helmet!