Get referrer value in express?

Question

I have a domain. I have two applications using this domain:

www.mydomain.com/first

www.mydomain.com/second

I do a redirect from www.mydomain.com/first to www.mydomain.com/second via the command: res.redirect('/second');

I'd like the application located at www.mydomain.com/second to then do a redirect back to www.mydomain.com/first dynamically (not via hardcoding the address).

So I was thinking that www.mydomain.com/second could get the request referrer field via the command: req.get('Referrer'). I was expecting this to return the value either www.mydomain.com/first, /first or first but it returns undefined.

How do I get a hold of the value?

It sounds to me like you're creating an infinite loop where first redirects to second which redirects to first which redirects to second and so on... — jfriend00, Feb 09 '17 at 09:37
@zeronone - The Express doc says that "the Referrer and Referer fields are interchangeable" with `req.get()` here: https://expressjs.com/en/api.html#req.get — jfriend00, Feb 09 '17 at 09:41
@jfriend00 Not really. The second application will set a cookie which is required by the first domain. So it may appear so, but the logic behind it is sound :) — basickarl, Feb 09 '17 at 09:45
I think you're banking on something that isn't in the spec. From the little bit I've read on this, the Referer header when redirecting to /second is not set to be /first. If what you're trying to do is to let your server know that the when the request comes in for /second that it came from a redirect, then you should either set a cookie or use a query parameter on the redirect URL. Your server can then see that. A query parameter would probably be better because it's temporal, but you could also set a cookie for the server to see and then remove the cookie when it is seen. — jfriend00, Feb 09 '17 at 10:06

score 0 · Answer 1 · answered Feb 09 '17 at 11:15

Because you want both applications to live on the same domain you can create a wrapper app that holds both 'children'.

var express = require('express');

var app1 = express();
app1.get('/first', function(req, res) {
  res.send('response from the first app');
})

var app2 = express();
app2.get('/second', function(req, res) {
  res.send('response from the second app');
});

var app = express();
app.use(app1);
app.use(app2);

app.listen(1337);

Because both apps now live on the same domain, you can redirect to what ever url you want as if it was within the same app.

Get referrer value in express?

1 Answers1