Getting a JSON object using node.js

Question

Im making a simple app to learn how node.js works. Using jquery and ajax i pass a JSON object to a node.js method. The problem is that i don't know how to get the specific JSON data in the node.js method.

client-side code:

        $(document).ready(function(){

        $('#guardarVehiculo').click(function(){
            var car = JSON.stringify(agregarCarro());
            $.ajax({
                type: 'POST',
                data: car,
                url: '/saveCar',
                dataType: 'JSON'
            }).done(function( response ) {
                console.log(response);
            });
        });

    });

    function addCar(){
        var id = getById('id').value;
        var brand = getById('brand').value;
        var model = getById('model').value;
        var transmission = getById('automatic').checked ? getById('automatico').value : getById('mechanic').value;
        var comment = getById('comment').value;

        var car = new Car(id, brand, model, transmission, comment);

        return car;

    }

node.js code:

var express = require('express');
var fs = require('fs');
var app = express();

app.get('/', function(req, res){
    res.sendFile(__dirname + "/index.html");
});

app.post('/saveCar', function(req, res){
    console.log(req);
});

var server = app.listen(8000, function(){
  var host = server.address().address;
  var port = server.address().port;
  console.log('Server running at: ' + host + ':' + port);
});

Thanks in advance.

If you're going to POST the data, you'll probably want a BodyParser that does this for you, otherwise GET data is easily available in req.query — adeneo
– adeneo, Commented Mar 5, 2016 at 6:21
Thanks for the advice, now i know what to use un every case. — DCruz22
– DCruz22, Commented Mar 5, 2016 at 6:30

DCruz22 · Accepted Answer · 2016-03-05 06:55:11Z

3

You could use the bodyParser middleware

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

and then req.body will contain the parsed JSON object:

app.post('/saveCar', function(req, res) {
    console.log(req.body);
});

There's just one gotcha. You need to set the proper Content-Type header when making the AJAX call so that the body parser knows that it should process JSON:

.ajax({
    type: 'POST',
    data: car,
    url: '/saveCar',
    contentType: 'application/json',
    dataType: 'JSON'
}).done(function( response ) {
    console.log(response);
});

edited Mar 5, 2016 at 6:55

DCruz22

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answered Mar 5, 2016 at 6:21

Darin Dimitrov

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1 Comment

DCruz22 Over a year ago

I was exactly looking for that. Thanks a lot!

Zeeshan Hassan Memon · Accepted Answer · 2016-03-05 06:48:31Z

1

Answer to understand flow.

JSON data posted from client is received in req.body.

req.body contains key-value pairs of data submitted in the request body. By default, it is undefined, and is populated when you use body-parsing middleware such as body-parser.

using body-parsing middleware to populate req.body as:

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

magic req.body will server JSON data, sent by client:

app.post('/save-car', function(req, res) {
    //hey! i am req.body and i have all data :)
});

answered Mar 5, 2016 at 6:48

Zeeshan Hassan Memon

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1 Comment

DCruz22 Over a year ago

Thanks for the explanation!

7urkm3n · Accepted Answer · 2016-03-05 06:58:47Z

0

Use BodyParser module.

Server:

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

Route:

cars{
  brand: "Tesla",
  model: "S-sport",
  color: "white"
}

app.post('/saveCar', function (req, res) {
    console.log(req.body);
    //to response back as Json.
    res.json(cars);
});

answered Mar 5, 2016 at 6:58

7urkm3n

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