Solution to issue 71 "undefined headers.origin"

[DaliuSinger]

I am not sure if this is cors issue or in general express issue however, there was a disscussion about that, so I decided to post my solution.

I was running into problems with getting req.headers.origin from "GET" method while using node.js with "express" router. However, using other methods, like POST req.headers.origin was working as expected.

In the discussion (https://github.com/expressjs/cors/issues/71) mentioned, was a solution to replace missing origin link with host:
req.headers.origin = req.headers.origin || req.headers.host;
However, I realised that referer always includes a full host link. Here is my solution that eventually replaces origin with another link scrambled from refefer.

app.use(function(req,res,next){
  if(!req.headers.origin) {
    if(req.headers.referer) {
      const url = new URL(req.headers.referer);
      req.headers.origin = url.origin;
    }
  }
  next();
});

What this does is scramble link from referer if original headers.origin is undefined and replaces correct link to headers.origin.
Hope this helps anyone who still has issues with this problem.

[dougwilson]

Thanks for sharing!