const express = require('express') const next = require('next') const LRUCache = require('lru-cache') const port = parseInt(process.env.PORT, 10) || 3000 const dev = process.env.NODE_ENV !== 'production' const app = next({ dev }) const handle = app.getRequestHandler() // This is where we cache our rendered HTML pages const ssrCache = new LRUCache({ length: function (n, key) { return n.toString().length + key.toString().length }, max: 100 * 1000 * 1000, // 100MB cache soft limit 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(port, err => { if (err) throw err console.log(`> Ready on http://localhost:${port}`) }) }) /* * NB: make sure to modify this to take into account anything that should trigger * an immediate page change (e.g a locale stored in req.session) */ function getCacheKey (req) { return `${req.url}` } async function renderAndCache (req, res, pagePath, queryParams) { const key = getCacheKey(req) // If we have a page in the cache, let's serve it if (ssrCache.has(key)) { res.setHeader('x-cache', 'HIT') res.send(ssrCache.get(key)) return } try { // If not let's render the page into HTML const html = await app.renderToHTML(req, res, pagePath, queryParams) // Something is wrong with the request, let's skip the cache if (res.statusCode !== 200) { res.send(html) return } // Let's cache this page ssrCache.set(key, html) res.setHeader('x-cache', 'MISS') res.send(html) } catch (err) { app.renderError(err, req, res, pagePath, queryParams) } }