How to retrieve POST query parameters?

Question

Here is my simple form:

<form id="loginformA" action="userlogin" method="post">
    <div>
        <label for="email">Email: </label>
        <input type="text" id="email" name="email"></input>
    </div>
<input type="submit" value="Submit"></input>
</form>

Here is my Express.js/Node.js code:

app.post('/userlogin', function(sReq, sRes){    
    var email = sReq.query.email.;   
}

I tried sReq.query.email or sReq.query['email'] or sReq.params['email'], etc. None of them work. They all return undefined.

When I change to a Get call, it works, so .. any idea?

Answer 1

For Express 4.1 and above

As most of the answers are using to Express, bodyParser, connect; where multipart is deprecated. There is a secure way to send post multipart objects easily.

Multer can be used as replacement for connect.multipart().

To install the package

$ npm install multer

Load it in your app:

var multer = require('multer');

And then, add it in the middleware stack along with the other form parsing middleware.

app.use(express.json());
app.use(express.urlencoded());
app.use(multer({ dest: './uploads/' }));

connect.json() handles application/json

connect.urlencoded() handles application/x-www-form-urlencoded

multer() handles multipart/form-data

Answer 2

use express-fileupload package

var app = require('express')();
var http = require('http').Server(app);
const fileUpload = require('express-fileupload')

app.use(fileUpload());

app.post('/', function(req, res) {
var email = req.body.email;
res.send('<h1>Email :</h1> '+email);
});

http.listen(3000, function(){
  console.log('Running Port:3000');
});

Answer 3

app.use(express.bodyParser());

Then for app.post request you can get post values via req.body.{post request variable}.

Answer 4

Backend:

import express from 'express';
import bodyParser from 'body-parser';

const app = express();
app.use(bodyParser.json()); // add a middleware (so that express can parse request.body's json)

app.post('/api/courses', (request, response) => {
  response.json(request.body);
});

Frontend:

fetch("/api/courses", {
  method: 'POST',
  body: JSON.stringify({ hi: 'hello' }), // stringify JSON
  headers: new Headers({ "Content-Type": "application/json" }); // add headers
});

Answer 5

You shoudn't use app.use(express.bodyParser()). BodyParser is a union of json + urlencoded + mulitpart. You shoudn't use this because multipart will be removed in connect 3.0.

To resolve that, you can do this:

app.use(express.json());
app.use(express.urlencoded());

It´s very important know that app.use(app.router) should be used after the json and urlencoded, otherwise it does not work!

Answer 6

Things have changed once again starting Express 4.16.0, you can now use express.json() and express.urlencoded() just like in Express 3.0.

This was different starting Express 4.0 to 4.15:

$ npm install --save body-parser

and then:

var bodyParser = require('body-parser')
app.use( bodyParser.json() );       // to support JSON-encoded bodies
app.use(bodyParser.urlencoded({     // to support URL-encoded bodies
  extended: true
})); 

The rest is like in Express 3.0:

Firstly you need to add some middleware to parse the post data of the body.

Add one or both of the following lines of code:

app.use(express.json());       // to support JSON-encoded bodies
app.use(express.urlencoded()); // to support URL-encoded bodies

Then, in your handler, use the req.body object:

// assuming POST: name=foo&color=red            <-- URL encoding
//
// or       POST: {"name":"foo","color":"red"}  <-- JSON encoding

app.post('/test-page', function(req, res) {
    var name = req.body.name,
        color = req.body.color;
    // ...
});

---

Note that the use of express.bodyParser() is not recommended.

app.use(express.bodyParser());

...is equivalent to:

app.use(express.json());
app.use(express.urlencoded());
app.use(express.multipart());

Security concerns exist with express.multipart(), and so it is better to explicitly add support for the specific encoding type(s) you require. If you do need multipart encoding (to support uploading files for example) then you should read this.