hmpps-open-layers-map/dist/scripts/tile-token-proxy/index.js

A native Web Component for displaying maps using OpenLayers.

import express from 'express';
import superagent from 'superagent';
import qs from 'qs';
let cachedToken = null;
function isTokenExpired(token) {
    const expiryTime = token.issued_at + parseInt(token.expires_in, 10) * 1000;
    return Date.now() >= expiryTime - 60_000; // refresh 1 min before expiry
}
async function fetchNewToken(authUrl, apiKey, apiSecret) {
    const response = await superagent
        .post(authUrl)
        .auth(apiKey, apiSecret)
        .set({ 'Content-Type': 'application/x-www-form-urlencoded' })
        .send(qs.stringify({ grant_type: 'client_credentials' }));
    const token = response.body;
    token.issued_at = Date.now();
    return token;
}
export function mojMapMiddleware({ authUrl, apiKey, apiSecret }) {
    if (!authUrl || !apiKey || !apiSecret) {
        throw new Error('Missing OS Maps credentials. Ensure authUrl, apiKey, and apiSecret are provided.');
    }
    const router = express.Router();
    router.get('/map/token', async (_req, res, next) => {
        try {
            if (!cachedToken || isTokenExpired(cachedToken)) {
                cachedToken = await fetchNewToken(authUrl, apiKey, apiSecret);
            }
            res.json({ access_token: cachedToken.access_token });
        }
        catch (error) {
            next(error);
        }
    });
    return router;
}