Express.js req.body undefined

Question

I have this as configuration of my Express server

app.use(app.router); 
app.use(express.cookieParser());
app.use(express.session({ secret: \"keyboard cat\" }         


        

Answer 1

Credit to @spikeyang for the great answer (provided below). After reading the suggested article attached to the post, I decided to share my solution.

When to use?

The solution required you to use the express router in order to enjoy it.. so: If you have you tried to use the accepted answer with no luck, just use copy-and-paste this function:

function bodyParse(req, ready, fail) 
{
    var length = req.header('Content-Length');

    if (!req.readable) return fail('failed to read request');

    if (!length) return fail('request must include a valid `Content-Length` header');

    if (length > 1000) return fail('this request is too big'); // you can replace 1000 with any other value as desired

    var body = ''; // for large payloads - please use an array buffer (see note below)

    req.on('data', function (data) 
    {
        body += data; 
    });

    req.on('end', function () 
    {
        ready(body);
    });
}

and call it like:

bodyParse(req, function success(body)
{

}, function error(message)
{

});

NOTE: For large payloads - please use an array buffer (more @ MDN)

Answer 2

The Content-Type in request header is really important, especially when you post the data from curl or any other tools.

Make sure you're using some thing like application/x-www-form-urlencoded, application/json or others, it depends on your post data. Leave this field empty will confuse Express.

Answer 3

Most of the time req.body is undefined due to missing JSON parser

const express = require('express');
app.use(express.json());

could be missing for the body-parser

const bodyParser  = require('body-parser');
app.use(bodyParser.urlencoded({extended: true}));

and sometimes it's undefined due to cros origin so add them

const cors = require('cors');
app.use(cors())

Answer 4

var bodyParser = require('body-parser');
app.use(bodyParser.json());

This saved my day.

Answer 5

As already posted under one comment, I solved it using

app.use(require('connect').bodyParser());

instead of

app.use(express.bodyParser());

I still don't know why the simple express.bodyParser() is not working...

Answer 6

in Express 4, it's really simple

const app = express()
const p = process.env.PORT || 8082

app.use(express.json())