No cache in Node.js server

Question

I have read that to avoid caching in Node.js, it is necessary to use:

res.header(\'Cache-Control\', \'no-cache, private         


        

Answer 1

Make use of a middleware to add no-cache headers. Use this middleware where-ever you intend to turn caching off.

function nocache(req, res, next) {
  res.header('Cache-Control', 'private, no-cache, no-store, must-revalidate');
  res.header('Expires', '-1');
  res.header('Pragma', 'no-cache');
  next();
}

Use the middleware in your routes definition:

app.get('/getfile', nocache, sendContent);

function sendContent(req, res) {
  var localPath = 'some-file';
  var mimeType = '';
  fs.readFile(localPath, 'utf8', function (err, contents) {
    if (!err && contents) {
      res.header('Content-Type', mimeType);
      res.header('Content-Length', contents.length);
      res.end(contents);
    } else {
      res.writeHead(500);
      res.end();
    }
  });
}

Let me know if this works for you.

Answer 2

After spelunking through source code for the express and fresh modules, this works from the server side (before res.end is called):

req.headers['if-modified-since'] = undefined;
req.headers['if-none-match'] = undefined;

Nasty, but it works.

Answer 3

You can use nocache Middleware to turn off caching.

npm install --save nocache

Apply the middleware to your app

const nocache = require('nocache');
...
app.use(nocache());

This disables browser caching.

Answer 4

Pylinux's answer worked for me, but upon further inspection, I found the helmet module for express that handles some other security features for you.

http://webapplog.com/express-js-security-tips/

To use, install and require helmet in express.js, then call app.use(helmet.noCache());

Answer 5

Set these headers on your response:

'Cache-Control': 'private, no-cache, no-store, must-revalidate'
'Expires': '-1'
'Pragma': 'no-cache'

If you use express you can add this middleware to have no cache on all requests:

// var app = express()
app.use(function (req, res, next) {
    res.header('Cache-Control', 'private, no-cache, no-store, must-revalidate');
    res.header('Expires', '-1');
    res.header('Pragma', 'no-cache');
    next()
});

Answer 6

You've already written your headers. I don't think you can add more after you've done that, so just put your headers in your first object.

res.writeHead(200, {
  'Content-Type': mimeType,
  'Content-Length': contents.length,
  'Accept-Ranges': 'bytes',
  'Cache-Control': 'no-cache'
});