Express.js

Express.js is popular for building web applications and APIs because it is lightweight, minimal, and unopinionated, allowing flexible project structure. It provides a simple routing system, middleware support, and seamless integration with Node.js, making server-side development fast and efficient. Its large ecosystem and active community contribute to quick prototyping and robust production-ready applications.

Example Use

This example assumes you are familiar with the @zeroad.network/token module, its use cases, and installation process. If not, please review the Node, Bun, and Deno page first.

The following demonstrates how to use the module with the express framework. It serves as a reference and starting point. Full examples are available in the examples section of our GitHub repository:

src/my-express-app/app.js
import { randomUUID } from "node:crypto";

import express from "express";
import { Site, FEATURES } from "@zeroad.network/token";

/**
 * Module initialization (once at startup)
 *
 * Option 1: Provide the pre-generated "Welcome Header" value, e.g., via process.env:
 *   const site = Site(process.env.ZERO_AD_NETWORK_WELCOME_HEADER_VALUE);
 *
 * Option 2: Pass an options object to define your site's feature list:
 *   const site = Site({
 *     siteId: 'd867b6ff-cb12-4363-be54-db4cec523235',
 *     features: [FEATURES.ADS_OFF, FEATURES.COOKIE_CONSENT_OFF, FEATURES.MARKETING_DIALOG_OFF]
 *   });
 */

const site = Site({
  // For demo purposes, we'll generate a siteId UUID
  siteId: randomUUID(),
  // Specify supported site features
  features: [FEATURES.ADS_OFF, FEATURES.COOKIE_CONSENT_OFF, FEATURES.MARKETING_DIALOG_OFF],
});

// -----------------------------------------------------------------------------
// Middleware
// -----------------------------------------------------------------------------
function tokenMiddleware(req, res, next) {
  // Inject the "X-Better-Web-Welcome" server header into every response
  res.setHeader(site.SERVER_HEADER_NAME, site.SERVER_HEADER_VALUE);

  // Parse the incoming user token from the client header
  // Attach parsed token data to request for downstream use
  req.tokenContext = site.parseToken(req.headers[site.CLIENT_HEADER_NAME]);

  next();
}

// -----------------------------------------------------------------------------
// Express app setup
// -----------------------------------------------------------------------------
const app = express();
app.use(tokenMiddleware);

app.get("/", (req, res) => {
  // Access parsed tokenContext for this request
  const tokenContext = req.tokenContext;

  // Render HTML template using tokenContext to adjust feature display
  const state = (value) => (value && '<b style="background: #b0b0b067">YES</b>') || "NO";
  const template = `
    <html>
      <body>
        <h1>Hello</h1>
        <h3>Contents of "tokenContext" variable for this request:</h3>
        <pre style="display: inline-block; border: 1px solid #5b5b5ba4; padding: 0.5rem; background: #b0b0b067">tokenContext = ${JSON.stringify(tokenContext, null, 2)}</pre>

        <h3>Site Feature toggles to be used while rendering this page:</h3>
        <ul>
          <li>Skip rendering Advertisements: ${state(tokenContext.ADS_OFF)}</li>
          <li>Skip rendering Cookie Consent Dialog: ${state(tokenContext.COOKIE_CONSENT_OFF)}</li>
          <li>Skip rendering Marketing Dialog: ${state(tokenContext.MARKETING_DIALOG_OFF)}</li>
          <li>Remove Content Paywall: ${state(tokenContext.CONTENT_PAYWALL_OFF)}</li>
          <li>Provide SaaS Access to Basic Subscription Plan: ${state(tokenContext.SUBSCRIPTION_ACCESS_ON)}</li>
        </ul>
      </body>
    </html>
  `;

  res.send(template);
});

app.get("/json", (req, res) => {
  // Return JSON response with tokenContext for API usage
  res.json({
    message: "OK",
    tokenContext: req.tokenContext,
  });
});

// -----------------------------------------------------------------------------
// Start Express server
// -----------------------------------------------------------------------------
app.listen(3000, () => {
  console.log(`Express server listening at port 3000
    · HTML template example:        http://localhost:3000
    · Plain JSON endpoint example:  http://localhost:3000/json`);
});

Example Use​

Example Use