Unobtrusive middle-ware for Expres.js to inspect request body - express

Question

Does there exist a thirdparty middleware or a way to create such middleware for Express.js that allows for intercepting all requests and inspecting the request's body content without affecting subsequent middleware such as bodyParser or route endpoints which may rely on the raw body such as express-http-proxy?
From what I can tell bodyParser itself seems to work in a somewhat obtrusive way that does not allow a route to override the default parsing behavior. The express documentation describes how request.body is filled in by middleware such as bodyParser. This behavior of bodyParser makes sense from simplicity and performance perspective but doesn't make it a great candidate for creating middleware which needs to inspect the contents of a request and let the remaining portion of the app working without modification. This is especially true seeing that depending on the parsing middleware the results may be in entirely different formats. After some digging I'm left wondering if it's generally possible to pull this off with express or perhaps once you read the request body you eliminate the ability to make use of further middleware such as bodyParser or express-http-proxy which expect to access the body directly.
Possibly related:
express req.pipe() does not work

Answer 1

You could always use the raw-body package with express middleware like so:
var getRawBody = require('raw-body');
var typer = require('media-typer');
app.use(function (req, res, next) {
getRawBody(req, {
length: req.headers['content-length'],
limit: '1mb',
encoding: typer.parse(req.headers['content-type']).parameters.charset
}, function (err, string) {
if (err) return next(err)
req.text = string
next()
})
})
If your only concern is performance, I wouldn't worry too much about body-parser as it's unlikely to have a massive performance impact. If you can, I'd suggest you just use body-parser with a typical express middleware app.use(..) to inspect the request body.