const express = require('express') const next = require('next') const LRUCache = require('lru-cache') const dev = process.env.NODE_ENV !== 'production' const app = next({ dir: '.', dev }) const handle = app.getRequestHandler() // This is where we cache our rendered HTML pages const ssrCache = new LRUCache({ max: 100, maxAge: 1000 * 60 * 60 // 1hour }) app.prepare() .then(() => { const server = express() // Use the `renderAndCache` utility defined below to serve pages server.get('/', (req, res) => { renderAndCache(req, res, '/') }) server.get('/blog/:id', (req, res) => { const queryParams = { id: req.params.id } renderAndCache(req, res, '/blog', queryParams) }) server.get('*', (req, res) => { return handle(req, res) }) server.listen(3000, (err) => { if (err) throw err console.log('> Ready on http://localhost:3000') }) }) function renderAndCache (req, res, pagePath, queryParams) { // If we have a page in the cache, let's serve it if (ssrCache.has(req.url)) { console.log(`CACHE HIT: ${req.url}`) res.send(ssrCache.get(req.url)) return } // If not let's render the page into HTML app.renderToHTML(req, res, pagePath, queryParams) .then((html) => { // Let's cache this page console.log(`CACHE MISS: ${req.url}`) ssrCache.set(req.url, html) res.send(html) }) .catch((err) => { app.renderError(err, req, res, pagePath, queryParams) }) }