index.js

// Require all the installs
import express from "express";
import session from "express-session";
import SteamSignIn from "steam-signin";
import dotenv from "dotenv";
dotenv.config();
import axios from "axios";

// Create a new SteamSignIn object
const realm = process.env.API_URL;
const signIn = new SteamSignIn(realm)

// Create an express app
const app = express();

// Let's set a port
const port = 3000;

// Set up the session
app.use(session({
    secret: process.env.SECRET,
    resave: false,
    saveUninitialized: true,
}));

// Spin up the server
app.listen(port, () => {
    console.log('Listening, port ' + port);
});

app.get('/api/v1/auth/steam', (req, res) => {
    res.statusCode = 302;
    res.setHeader(
        "Location",
        signIn.getUrl(process.env.API_URL + '/api/v1/auth/steam/return')
    )
    res.end();
});

app.get('/api/v1/auth/steam/return', async (req, res) => {
    res.setHeader('Content-Type', 'text/plain');
    try {
        let steamId = await signIn.verifyLogin(req.url);

        const steamid64 = steamId.getSteamID64();
        const response = await axios.get(`https://api.steampowered.com/ISteamUser/GetPlayerSummaries/v0002/?key=${process.env.STEAM_API_KEY}&steamids=${steamid64}`)
        const { avatarfull, personaname } = response.data.response.players[0];

        req.session.user = {
            steamid64,
            avatarfull,
            personaname,
        }
        await req.session.save()
    
        res.redirect(process.env.API_URL);
    } catch (error) {
        console.error(error);
        return res.status(500).send('There was an error signing in.');
    }
});

app.get('/', (req, res) => {
    const { user } = req.session;
    res.status(200).send(user);
});