API Link User Token Authentication

import { sign } from "jsonwebtoken";

const userData = {
  userId: "abc123",              // ✅ REQUIRED: Unique ID for this user
  email: "[email protected]",     // ⚠️ Optional but recommended
  locale: "en",                  // ✅ REQUIRED: Language code (e.g., "en", "fr", "es")
};

function signUserToken(input) {
  const clientSecret = "YOUR_CLIENT_SECRET"; // From API Configuration
  return sign(input, clientSecret, { expiresIn: "1h" });
}

const userToken = signUserToken(userData);
console.log("Generated token:", userToken);

const domain = "loyalty.mycompany.com";     // Your Nudj domain
const clientId = "YOUR_CLIENT_ID";          // From API Configuration
const userToken = "YOUR_GENERATED_TOKEN";   // From previous step

const linkUrl = `https://${domain}/api/link?userToken=${userToken}&clientId=${clientId}`;

// Redirect the user to this URL
window.location.href = linkUrl;

const express = require("express");
const { sign } = require("jsonwebtoken");
const app = express();

// These come from your Nudj API Configuration
const NUDJ_CLIENT_ID = "your_client_id";
const NUDJ_CLIENT_SECRET = "your_client_secret";
const NUDJ_DOMAIN = "loyalty.mycompany.com";

// Endpoint that generates the login link
app.get("/nudj-login-link", (req, res) => {
  // Get the authenticated user from your system
  const user = req.user; // Assuming you have authentication middleware

  // Create the token payload
  const tokenPayload = {
    userId: user.id,
    email: user.email,
    locale: user.preferredLanguage || "en",
    username: user.displayName,
  };

  // Sign the token
  const userToken = sign(tokenPayload, NUDJ_CLIENT_SECRET, {
    expiresIn: "1h",
  });

  // Build the Nudj login URL
  const loginUrl = `https://${NUDJ_DOMAIN}/api/link?userToken=${userToken}&clientId=${NUDJ_CLIENT_ID}`;

  // Return the URL to your frontend
  res.json({ loginUrl });
});

app.listen(3000, () => console.log("Server running"));

import { useEffect, useState } from "react";

export function NudjLoginButton() {
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(null);

  const handleLogin = async () => {
    setLoading(true);
    setError(null);

    try {
      // Call your backend to get the login URL
      const response = await fetch("/nudj-login-link");
      const { loginUrl } = await response.json();

      // Redirect to Nudj
      window.location.href = loginUrl;
    } catch (err) {
      setError("Failed to generate login link");
      setLoading(false);
    }
  };

  return (
    <div>
      <button onClick={handleLogin} disabled={loading}>
        {loading ? "Connecting..." : "Go to Loyalty Program"}
      </button>
      {error && <p style={{ color: "red" }}>{error}</p>}
    </div>
  );
}