Develop Reference

The simplest possible req.body is always empty

I'm just trying to pass the simplest data possible (at the moment, for test purposes) from client to server with a POST request, but I keep getting empty or undefined logs on req.body.
Server:
//jshint esversion:6
const express = require("express");
const bodyParser = require("body-parser");
const mongoose = require("mongoose");
const app = express();
app.set('view engine', 'ejs');
app.use(bodyParser.urlencoded({extended: true}));
app.use(express.static("public"));
mongoose.connect("mongodb://localhost:27017/sandbox", {useNewUrlParser: true});
app.get("/", function(req, res){
res.render("home", {});
})
app.post("/filter", function(req, res){
console.log(req.body);
res.redirect("/");
})
app.listen(3000, function() {
console.log("Server started on port 3000");
});
Client (version 1):
var yourdata = { "name": "The pertinent data"};
console.log(document.body)
$.ajax({
url : "/filter",
type: "POST",
dataType:'text',
data : yourdata,
contentType: "application/json",
});
Client (version 2):
var payload = {data: "The pertinent data"};
var req = new XMLHttpRequest();
req.open('POST', '/filter' , true);
req.send(JSON.stringify(payload))
I added both attempts at a code client-side, but I'm happy with whichever method works. Ideally I'll eventually tap into the payload or data with req.body.payload or something, but at the moment that's just giving me an undefined.
I've looked into quite a few similar posts and usually they were missing the "app.use(bodyParser.urlencoded({extended: true}));" or "app.use(bodyParser.json());" I've tried adding and removing those, changing from true to false, still empty.
The console.log(document.body) on the client script does work, giving me the expected body on the browser console, and the server route is working too, eventually redirecting to home.
I can't see how the issue is something I'm doing wrong on the client side, but oddly enough, if I create a form, with an action to that route, and submit, it seems to send the req.body normally. E.g.:
<form class="form" action="/filter" method="post">
<input name="newName" placeholder="Name">
<button type="submit">Submit</button>
</form>
That does indeed log a JSON object e.g.: { newName: 'John'}
In case it might be relevant, the HTML is the simplest one possible, almost empty, only really doing the pertinent links.
Thanks all in advance!

You need three things:
A request body encoded in some data format
A content-type request header which says which data format you are using
Body parsing middleware that can process that data format
When you submit a form, with no enctype attribute, it will submit the data in URL encoded format with the right content type. This matches the body parsing middleware you have (bodyParser.urlencoded({extended: true})).
1, 2, and 3 are all good.
Note that it does not create a JSON object. The client produces URL encoded data. The server parses that into a JavaScript object. There is no JSON.
Client (version 1):
Here you are passing an object to jQuery so it will URL encode the data in it and would normally set the correct content type.
It is failing because you have contentType: "application/json",.
Since you are falsely claiming that you are sending JSON, bodyParser.urlencoded ignores it.
If you had a JSON body parser in place, it would error because the data is not JSON.
1 and 3 are good, but 2 is a lie.
Remove the contentType property.
Client (version 2):
Now you are JSON encoding the data, but you aren't setting the content type request header, and you don't have body parsing middleware that can handle JSON.
3 is bad, and either 1 or 2 is too.

For the server-side part of your application, you need something that moves the body of the request out of the request string itself to a clear, easy-to-read, and use variable. The express json() method (middleware) does that exactly.
Use the express JSON parser middleware as follows:
app.use(express.json())
Code:
const express = require("express");
// const bodyParser = require("body-parser");
const mongoose = require("mongoose");
const app = express();
app.use(express.json()); // 👈 here
// ... the rest of your code
Just few notes about the middleware you're using
app.use(bodyParser.urlencoded({extended: true}));
We usually use this middleware to parse the HTML forms data, in other words, it's just like the express middleware express.json(), but the difference here is that it parses the requests which have the content type of HTML forms, while the express.json() converts the ones which have the content-type of application/json.
If you're using express v +4, you don't need the bodyParser package, express has the .urlencoded() and the .json() methods built into the express package itself, you can use them just as express.json() and express.urlencoded().
Tip, you can have both middlewares, the JSON parser, and the HTML form content type parser, when the server receives a content-type JSON, the express.json() middleware will parse the request body, and if the server receives an HTML form content-type the urlencoded middleware will fire:
code example:
const express = require("express");
// const bodyParser = require("body-parser"); ❌ not needed
const mongoose = require("mongoose");
const app = express();
app.use(express.json()); // 👈 here
app.use(express.urlencoded({ extended: true })) // 👈 here
// ... the rest of your code

I can not get request in body format in Node.js

I have problems receiving request in body format on my server.
I am using Express version 4.17.1. The documentation indicates that I don't have to use body-parserer, but I can do it directly with the express functionality "express.json ()"
However, I've been trying to get it to work for a long time but nothing happens: the console does not show anything. It seems that it does not recognize the request at all.
I'm doing all the request from Postman in body format JSON.
This is my code:
const express = require("express");
const formidable = require("express-formidable");
const cors = require("cors");
const dotenv = require("dotenv").config();
const app = express();
app.use(express.urlencoded({ extended: true }));
app.use(express.json());
app.use(formidable());
app.use(cors());
(...)
app.post("/list", async (req, res) => {
try {
console.log(req.body);
} catch (error) {
return res.status(400).json({ message: error.message });
}
});
What am I doing wrong?
Thank you very much for your time and help in advance.

Express parse request body according to defined type in Content-Type header. Try to do request with header Content-Type: application/json.

How to access req.body via expressjs?

I cant access body when getting expressjs request
My main server.js file
app.use(express.urlencoded({extended: true}));
app.use(express.json());
app.use(router);
My router.js file
const express = require("express");
const articlesContr = require("./../controllers/articlesContr.js");
const router = express.Router();
router
.get("/articles", articlesContr.handleGet)
.post("/articles", articlesContr.handlePost)
.put("/articles", articlesContr.handleUpdate)
.delete("/articles", articlesContr.handleDelete);
adminPanelContr.js
const controller = {
handleGet: (req, res) => {
const query = req._parsedUrl.query;
const parsedQuery = querystring.parse(query);
// res.send(productsDb.getItem(parsedQuery));
console.log(req)
res.send(JSON.stringify(req.body))
}
};

GET requests don't have body parameters. Ordinarily .get() handler functions don't look for them.
If you use the same handler function for GET and other (POST, PUT, PATCH, DELETE) requests, you need logic to avoid looking at the body when you get a GET.
When you send a request with a JSON body, don't forget to tell your server it's JSON by including a Content-Type: application/json HTTP header. That way you're sure express will invoke its express.json middleware to parse the body into the req.body object.
When you .get() a GET, you don't get a request body. There's gotta be some sort of doggerel poetry in there someplace.
If you use res.json(object) rather than res.send(JSON.stringify(object)) express does a good job of setting the HTTP response headers to useful values for JSON.
And, I'm sure you know this: Responding to a request with its own request body is a little strange.

Handling form input in nodejs

I would like user to submit a URL as form input (e.g: "http://api.open-notify.org/astros.json") and read the content from the submitted URL.
I'm not sure if my current approach is correct. What should i put in the URL field below?
var options = {
url: '....',
method: 'GET',
headers: {'Content-Type' : 'application/x-www-form-urlencoded' }
}

You could do something like this (I guess this is what you want):
I suggest using request-promise package
const rp = require('request-promise');
// post router
app.post('/readUrl', async (req, res) => {
const uri = req.body.url // http://api.open-notify.org/astros.json
const options = {
uri,
headers: {
// maybe set some headers to accept other formats of response
},
// Automatically parses the JSON string in the response
json: true
};
const data = await rp(options);
// data is json
res.json(data);
})

It seems like you already have the Express logic loaded. IMO, if you have express already working, create a post route that the user can hit:
app.post("/form",(req,res)=>{
//See the request body here.
console.log(req.body)
);
You would then make your AJAX call with the URL you have above. It is worth noting that you will need a body parser on your server.js file.
const bodyParser = require("body-parser");
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
The plugin allows easier parsing on the server side from the client.

How to access the request body when POSTing using Node.js and Express?

I have the following Node.js code:
var express = require('express');
var app = express.createServer(express.logger());
app.use(express.bodyParser());
app.post('/', function(request, response) {
response.write(request.body.user);
response.end();
});
Now if I POST something like:
curl -d user=Someone -H Accept:application/json --url http://localhost:5000
I get Someone as expected. Now, what if I want to get the full request body? I tried doing response.write(request.body) but Node.js throws an exception saying "first argument must be a string or Buffer" then goes to an "infinite loop" with an exception that says "Can't set headers after they are sent."; this also true even if I did var reqBody = request.body; and then writing response.write(reqBody).
What's the issue here?
Also, can I just get the raw request without using express.bodyParser()?

Starting from express v4.16 there is no need to require any additional modules, just use the built-in JSON middleware:
app.use(express.json())
Like this:
const express = require('express')
app.use(express.json()) // <==== parse request body as JSON
app.listen(8080)
app.post('/test', (req, res) => {
res.json({requestBody: req.body}) // <==== req.body will be a parsed JSON object
})
Note - body-parser, on which this depends, is already included with express.
Also don't forget to send the header Content-Type: application/json

Express 4.0 and above:
$ npm install --save body-parser
And then in your node app:
const bodyParser = require('body-parser');
app.use(bodyParser);
Express 3.0 and below:
Try passing this in your cURL call:
--header "Content-Type: application/json"
and making sure your data is in JSON format:
{"user":"someone"}
Also, you can use console.dir in your node.js code to see the data inside the object as in the following example:
var express = require('express');
var app = express.createServer();
app.use(express.bodyParser());
app.post('/', function(req, res){
console.dir(req.body);
res.send("test");
});
app.listen(3000);
This other question might also help: How to receive JSON in express node.js POST request?
If you don't want to use the bodyParser check out this other question: https://stackoverflow.com/a/9920700/446681

As of Express 4, the following code appears to do the trick.
Note that you'll need to install body-parser using npm.
var express = require('express');
var bodyParser = require('body-parser');
var app = express();
app.use(bodyParser.urlencoded({ extended: false }));
app.listen(8888);
app.post('/update', function(req, res) {
console.log(req.body); // the posted data
});

For 2019, you don't need to install body-parser.
You can use:
var express = require('express');
var app = express();
app.use(express.json())
app.use(express.urlencoded({extended: true}))
app.listen(8888);
app.post('/update', function(req, res) {
console.log(req.body); // the posted data
});

You should not use body-parser it is deprecated. Try this instead
const express = require('express')
const app = express()
app.use(express.json()) //Notice express.json middleware
The app.use() function is used to mount the specified middleware function(s) at the path which is being specified. It is mostly used to set up middleware for your application.
Now to access the body just do the following
app.post('/', (req, res) => {
console.log(req.body)
})

var express = require('express');
var bodyParser = require('body-parser');
var app = express();
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json())
var port = 9000;
app.post('/post/data', function(req, res) {
console.log('receiving data...');
console.log('body is ',req.body);
res.send(req.body);
});
// start the server
app.listen(port);
console.log('Server started! At http://localhost:' + port);
This will help you. I assume you are sending body in json.

This can be achieved without body-parser dependency as well, listen to request:data and request:end and return the response on end of request, refer below code sample. ref:https://nodejs.org/en/docs/guides/anatomy-of-an-http-transaction/#request-body
var express = require('express');
var app = express.createServer(express.logger());
app.post('/', function(request, response) {
// push the data to body
var body = [];
request.on('data', (chunk) => {
body.push(chunk);
}).on('end', () => {
// on end of data, perform necessary action
body = Buffer.concat(body).toString();
response.write(request.body.user);
response.end();
});
});

In my case, I was missing to set the header:
"Content-Type: application/json"

Try this:
response.write(JSON.stringify(request.body));
That will take the object which bodyParser has created for you and turn it back into a string and write it to the response. If you want the exact request body (with the same whitespace, etc), you will need data and end listeners attached to the request before and build up the string chunk by chunk as you can see in the json parsing source code from connect.

The accepted answer only works for a body that is compatible with the JSON format. In general, the body can be accessed using
app.use(
Express.raw({
inflate: true,
limit: '50mb',
type: () => true, // this matches all content types
})
);
like posted here. The req.body has a Buffer type and can be converted into the desired format.
For example into a string via:
let body = req.body.toString()
Or into JSON via:
let body = req.body.toJSON();

If you're lazy enough to read chunks of post data.
you could simply paste below lines
to read json.
Below is for TypeScript similar can be done for JS as well.
app.ts
import bodyParser from "body-parser";
// support application/json type post data
this.app.use(bodyParser.json());
// support application/x-www-form-urlencoded post data
this.app.use(bodyParser.urlencoded({ extended: false }));
In one of your any controller which receives POST call use as shown below
userController.ts
public async POSTUser(_req: Request, _res: Response) {
try {
const onRecord = <UserModel>_req.body;
/* Your business logic */
_res.status(201).send("User Created");
}
else{
_res.status(500).send("Server error");
}
};
_req.body should be parsing you json data into your TS Model.

I'm absolutely new to JS and ES, but what seems to work for me is just this:
JSON.stringify(req.body)
Let me know if there's anything wrong with it!

Install Body Parser by below command
$ npm install --save body-parser
Configure Body Parser
const bodyParser = require('body-parser');
app.use(bodyParser);
app.use(bodyParser.json()); //Make sure u have added this line
app.use(bodyParser.urlencoded({ extended: false }));

What you claim to have "tried doing" is exactly what you wrote in the code that works "as expected" when you invoke it with curl.
The error you're getting doesn't appear to be related to any of the code you've shown us.
If you want to get the raw request, set handlers on request for the data and end events (and, of course, remove any invocations of express.bodyParser()). Note that the data events will occur in chunks, and that unless you set an encoding for the data event those chunks will be buffers, not strings.

You use the following code to log post data:
router.post("/users",function(req,res){
res.send(JSON.stringify(req.body, null, 4));
});