prerender-hapi

Hapi plugin for Prerender.io. Intercepts requests from bots and crawlers and serves prerendered HTML, so your JavaScript-rendered app is fully indexable by search engines and social media scrapers.

Compatible with @hapi/hapi v21+ and Node.js 18+.

Installation

npm install prerender-hapi

Usage

constHapi=require('@hapi/hapi');constserver=Hapi.server({host: 'localhost',port: 3000});awaitserver.register({plugin: require('prerender-hapi'),options: {token: 'YOUR_PRERENDER_TOKEN'}});

The plugin registers an onRequest extension that transparently proxies bot requests to Prerender.io and returns the prerendered HTML. Regular browser requests are unaffected.

Options

Option	Type	Default	Description
token	string	process.env.PRERENDER_TOKEN	Your Prerender.io token
serviceUrl	string	process.env.PRERENDER_SERVICE_URL or https://service.prerender.io/	Prerender service URL (use this for self-hosted Prerender)
protocol	string	null	Force a protocol (http or https). Defaults to the server's protocol
beforeRender	async function(request)	async () => null	Called before each prerender request. Return a cached response object { status, headers, body } to skip the Prerender.io call
afterRender	async function(request, response)	async () => {}	Called after a successful prerender. Use this to cache the response. Can be sync or async

Environment variables

PRERENDER_TOKEN=your_token_here
PRERENDER_SERVICE_URL=https://service.prerender.io/ # optional

Self-hosted Prerender

awaitserver.register({plugin: require('prerender-hapi'),options: {serviceUrl: 'http://your-prerender-server:3000'}});

Caching example

constcache=newMap();awaitserver.register({plugin: require('prerender-hapi'),options: {token: 'YOUR_PRERENDER_TOKEN',beforeRender: async(request)=>{returncache.get(request.url.href)||null;},afterRender: (request,response)=>{cache.set(request.url.href,response);}}});

How it works

Requests are prerendered when all of the following are true:

• The HTTP method is GET
• The User-Agent matches a known bot/crawler (Googlebot, Bingbot, Twitterbot, GPTBot, ClaudeBot, etc.)
  — OR the URL contains _escaped_fragment_
  — OR the X-Bufferbot header is present
• The URL does not end with a static asset extension (.js, .css, .png, .woff2, .webp, etc.) — matched case-insensitively

Everything else passes through to your normal route handlers.

License

MIT