HTTP Response not sending X-Auth-Token in Header

Question

I´m trying to make a post request to a third party API.

In this request I have to send my username and password on the header, and It will return a response header with the X-Auth_token. The problem is that I´m not getting the X-Auth-Token in the header if I make the posto from a client to my server and then to the API. If I make the request from Postman directly to the API url, it works fine.

This is the code:

SERVER

app.post("/signin", async (req, res) => {
  console.log("BODY", await req.body);
  try {
    const xToken = await axios.post(loginUrl, {
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",

        "X-Username": req.body.username,
        "X-Password": req.body.password,
      },
    });
    console.log(xToken.headers);

    //res.send(xToken);
  } catch (error) {
    console.log("SERVER Error: ", error.message);
  }
});

CLIENT

const signin = async () => {
  try {
    const TOKEN = await axios.post("http://localhost:3000/signin", {
      username: "AGU",
      password: "MIOTTI",
    });

    
    console.log("TOKEN", TOKEN);

    return TOKEN;
  } catch (error) {
    console.log("CLIENT Error: ", error.message);
  }
};

signin();

What can be the problem?

some data of postman:

This is the response header when you try to make the post with postman directly to https://api.remarkets.primary.com.ar/auth/getToken:

and this is the response header when you make the reques to the serven on express:

Answer 1

The Server side as server.js file

const express = require("express")
const axios = require('axios')
const cors = require("cors")
const bodyParser = require('body-parser')
const corsOptions = {
    exposedHeaders: 'Authorization',
};

const app = express()
app.use(cors(corsOptions))
app.use(bodyParser())

const loginUrl = 'https://api.remarkets.primary.com.ar/auth/getToken'

app.post("/signin", async (req, res) => {
    console.log("BODY", await req.body);
    const response = await axios.post(
        url = loginUrl,
        '',
        config = {
            headers: {
                "X-Username": req.body.username,
                "X-Password": req.body.password,
            }
        })
    return res.send(response.headers["x-auth-token"])
});

app.listen(3000, () => { console.log("Listening on :3000") })

The Cliet side as client.js file

const axios = require('axios')
const signin = async () => {
    try {
        const response = await axios.post("http://localhost:3000/signin", {
            username: "<your id>",
            password: "<your password>",
        });
        return Promise.resolve(response.data);
    } catch (error) {
        return Promise.reject(error);
    }
};

signin()
    .then(token => {
        console.log('token is : ' + token);
    })
    .catch(error => {
        console.log(error.message);
    });

Install dependencies

npm install express axios cors body-parser

Confirmed dependencies

$ npm ls --depth=0
@ D:\temp\working
├── axios@1.3.2
├── body-parser@1.20.1
├── cors@2.8.5
└── express@4.18.2

Run Server first

node server.js

Run client later

node client.js

Result in client

References

Axios get access to response header fields

Unable to access JSON property with "-" dash