Axios post sending body but body is undefined with fetch and Postman

Question

I'm not able to send a post body with fetch or Postman, but I can send the body with Axios.

Axios returns: User name = Fred, password is Flintstone

But Postman and fetch both return User name = undefined, password is undefined

How can I get the post body with fetch and postman?

Server File

const express = require("express");
const bodyParser = require("body-parser");
const app = express();
const axios = require("axios");

app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

app.post("/login", (req, res) => {
  var user_name = req.body.user;
  var password = req.body.password;
  console.log("User name = " + user_name + ", password is " + password);
  res.end("yes");
});

app.listen(3000, () => {
  console.log("Started on PORT 3000");
});

Axios

axios.post("http://localhost:3000/login", {
  user: "Fred",
  password: "Flintstone",
});

Fetch (client side)

fetch("http://localhost:3000/login", {
  method: "POST",
  body: JSON.stringify({ user: "Fred", password: "Flintstone" }),
  mode: "no-cors",
});

Postman

score 2 · Answer 1 · answered Oct 29 '20 at 14:07

2

In Postman you are trying to send JSON data as a text. Change the type of data sent from Text (what you have now) to JSON in Postman.

Also as a suggestion, you should leave 1 bodyParser in your server file

For fetch() I recommend you to take a look at this question, some adjustments must be made Fetch: POST json data

answered Oct 29 '20 at 14:07

Runsis

831
9
19

Thanks this solved my postman issue. And yea I wasn't sure about the bodyparser, thanks. – Dashiell Rose Bark-Huss Oct 29 '20 at 14:21
1

No problem, also try using `const` and `let` instead of `var` :) – Runsis Oct 29 '20 at 14:26

score 2 · Accepted Answer · answered Oct 29 '20 at 14:08

fetch doesn't default to posting JSON, which is why you had to encode the body explicitly. You also need to tell the server that you are sending JSON.

You can't do that without permission from CORS, so you must not set the mode to no-cors.

const headers = new Headers();
headers.append("Content-Type", "application/json");

fetch("http://localhost:3000/login", {
  method: "POST",
  body: JSON.stringify({ user: "Fred", password: "Flintstone" }),
  headers
});

The problem with Postman is probably the same (but not visible in the UI screenshot): You need to set the Content-Type header.

thanks. This worked combined with installing cors: `npm i cors` and adding `const cors = require("cors"); app.use(cors());` to the server file. — Dashiell Rose Bark-Huss, Oct 29 '20 at 14:19

score -2 · Answer 3 · answered Oct 29 '20 at 14:04

-2

Try this:

app.post("/login", (req, res) => {
  var user_name = req.body.user;
  var password = req.body.password;
  console.log("User name = " + user_name + ", password is " + password);
  res.json({ "user name": user_name, "password": password });
});

answered Oct 29 '20 at 14:04

ian natividad

79
6

1

Still got the same problem, and it also isn't sent back in the response. – Dashiell Rose Bark-Huss Oct 29 '20 at 14:08

Axios post sending body but body is undefined with fetch and Postman

Server File

Axios

Fetch (client side)

Postman

3 Answers3