Getting "first argument must be a string or Buffer" error

Question

// call the packages
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var figlet = require('figlet');
var querystring = require('querystring');
var http = require('http');
var fs = require('fs');
var request = require('request');

// configure app to use bodyParser()
// this will let app get the data from a POST
app.use(bodyParser.urlencoded({
    extended: true
}));
app.use(bodyParser.text());

// set port
var port = process.env.PORT || 8082;

// get an instance of the express Router
var router = express.Router();


// middleware to use for all requests
router.use(function(req, res, next) {

    // do logging
    console.log('UnitGener router invoking');
    // go to the next routes and don't stop here
    next();
});

// test route to make sure everything is working (accessed at GET http://localhost:8082/api)
router.get('/status', function(req, res) {
    res.json({
        message: 'UnitGener is ready to work!'
    });
});


//noinspection JSUnresolvedFunction
router.route('/function')

    .post(function(req, res) {
        console.log(req.body);
        var formatted = req.body;


        request.post({
            headers: {
                'content-type': 'application/x-www-form-urlencoded'
            },
            url: 'http://localhost:5000/generate',
            body: formatted
        }, function(error, response, body) {
            console.log(body);
        });

    });

app.use('/api', router);
app.listen(port);
});

Here is my complete code for creating a POST route with the given configs and then I am calling another post route within the post method. But I am getting the "throw new TypeError('first argument must be a string or Buffer');" this error. I did some google finding and did some changes also , non of them worked and still find it hard to point the error. I changed the body: formatted to body: formatted.toString() also but didn't work. Please give me some advice to find this out. Its a huge help for me.

Thanks in Advance

Solution 1

The error is in the request call. To submit the form correctly use

    request.post({
        url: 'http://localhost:5000/generate',
        form: formatted
    }, function(error, response, body) {
        console.log(body);
    });

I encourage you to use the npm module request-promise-native: https://github.com/request/request-promise-native https://www.npmjs.com/package/request-promise

var rp = require('request-promise');

var options = {
    method: 'POST',
    uri: 'http://api.posttestserver.com/post',
    body: {
        some: 'payload'
    },
    json: true // Automatically stringifies the body to JSON 
};

rp(options)
    .then(function (parsedBody) {
        // POST succeeded... 
    })
    .catch(function (err) {
        // POST failed... 
    });

Solution 2

your body is expected to be Buffer try this, json:true in request option

 request.post({
        headers: {
            'content-type': 'application/x-www-form-urlencoded'
        },
        url: 'http://localhost:5000/generate',
        body: formatted,
        json:true
    }, function(error, response, body) {
        console.log(body);
    });

Solution 3

why are you writing:

router.route('/function')
  .post(function(req, res) {

try:

router.post('/function', function(req, res) {

Comments

[Josh F]

Thank you! I was having this issue, and adding json: true in the request options is all that was needed to fix. Much appreciated.

[Lee O.]

I was using request-promise-native and was getting this same error. Adding the json: true to the options was what solved the issue for me.