How to use `bodyParser.raw()` to get raw body? - node.js

Question

I am creating a web API using Express.
The feature is to allow API users to send a file to the server.
Here's my app setup code:
var express = require('express');
var path = require('path');
// ...
var bodyParser = require('body-parser');
var routes = require('./routes/index');
var users = require('./routes/users');
// API routes
var images = require('./routes/api/img');
var app = express();
app.use(bodyParser.raw());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(express.static(path.join(__dirname, 'public')));
app.use('/', routes);
app.use('/api', images);
// ...
module.exports = app;
Please notice that I am using app.use(bodyParser.raw());.
How do I get the raw bytes from POST requests?
const express = require('express');
const router = express.Router();
/* POST api/img */
router.post('/img', function(req, res, next) {
// how do I get the raw bytes?
});
module.exports = router;

Answer 1

if you want to send a raw data and get with body parser you just configure this way:
app.use(bodyParser.raw({ inflate: true, limit: '100kb', type: 'text/xml' }));
That behavior doesn't corrupt the body content.

Answer 2

To parse all content types I use:
app.use(
express.raw({
inflate: true,
limit: '50mb',
type: () => true, // this matches all content types
})
);
To get the raw body in just a single route:
app.put('/upload', express.raw({ inflate: true, limit: '50mb', type: () => true }), async (req, res) => {
res.json({ bodySize: req.body.length });
});
In that case note that the previously app.use()'d body parsers (json for example) are executed first - so check that req.body is indeed a Buffer, otherwise a malicious caller could send something like {"length":9999999} with Content-Type: application/json.

Answer 3

The parsed body should be set on req.body.
Keep in mind that middleware is applied in the order you set it with app.use, my understanding is that applying the bodyParser multiple times as you have will attempt to parse the body in that order, leaving you with the result of the last middleware to operate on req.body, i.e. since both bodyParser.json() and bodyParser.raw() both accept any inputs, you will actually end up attempting to parse everything from a Buffer into JSON.