Prevent express body-parser from removing body prior to request.pipe

I am trying to create a simple express middleware filter which should look at the POST body and determine if it should be piped to the correct server, or blocked. If I use body-parser it appears that I do get the req.body available to me, but it disappears from the request when I pipe the request to another external server.

The way I have tried to solve this is the following:

//Router
router.route('')
    .post(authController.isAuthenticated,
        urlHelper.bodyParser,             //Without these two, everything pipes correctly
        urlHelper.filterBasedOnSomething, //Without these two, everything pipes correctly
        urlHelper.pipeToTrustedZone);

In urlHelper:

const filterBasedOnSomething = function (req, res, next) {
        if (req.body
            && req.body.something === 'some string'
            && req.body.somethingElse === 'some other value') {
            return res.status(403).send("You shall not pass");
        } else {
            next();
        }
    }
const pipeToTrustedZone = function (req, res) {
        //Here we are figuring out the correct forwarding url. This is simplified a little for the question, but it is well tested and works.
        var url = getProxiedPath(req.baseUrl) + req.originalUrl;
        req.pipe(request({ qs: req.query, uri: url }).on('error', function (err) {
            log.info(err);
            return res.sendStatus(400);
        }))
            .pipe(res);

};
module.exports = {
  bodyParser: require('body-parser').json(),
  filterBasedOnSomething: filterBasedOnSomething,
  pipeToTrustedZone: pipeToTrustedZone,
  //..
}

This seem to give me the req.body in my filter-method, but the body is consumed and is not received after it has been piped forward. I have tried multiple things, like req.emit('data', JSON.stringify(req.body)); and req.write(.., but it all seem to fail.

Is there a way for me to look at the request body before piping it further without deleting it? Or is there an inherit problem with my approach?

I have found multiple github issues and SO questions relating to this, but I haven't been successful in getting any of those approaches to work.:

https://github.com/expressjs/body-parser/issues/74

Writing express middleware to get raw request body before body-parser

https://github.com/expressjs/body-parser/issues/94

via Cort3z