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May 25, 2020 22:44
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Angular Express Server with Redis Caching
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import 'zone.js/dist/zone-node'; | |
import { APP_BASE_HREF } from '@angular/common'; | |
import { ngExpressEngine } from '@nguniversal/express-engine'; | |
import * as express from 'express'; | |
import { existsSync } from 'fs'; | |
import { join } from 'path'; | |
import * as redis from 'redis'; | |
import { AppServerModule } from './src/main.server'; | |
// The Express app is exported so that it can be used by serverless Functions. | |
export function app(): express.Application { | |
const server = express(); | |
const distFolder = join(process.cwd(), 'dist/browser'); | |
const indexHtml = existsSync(join(distFolder, 'index.original.html')) | |
? 'index.original.html' | |
: 'index'; | |
// Redis cache client | |
const redisClient = redis.createClient(); | |
// Creates a cache key using the request URL | |
const cacheKey: (req: express.Request) => string = (req) => | |
`ssr_${req.originalUrl}`; | |
// Universal express-engine | |
server.engine( | |
'html', | |
ngExpressEngine({ | |
bootstrap: AppServerModule, | |
}) | |
); | |
server.set('view engine', 'html'); | |
server.set('views', distFolder); | |
// Middleware to send a cached response if one exists | |
const cachedResponse: express.RequestHandler = (req, res, next) => | |
redisClient.get(cacheKey(req), (error: Error, reply: string) => { | |
if (reply?.length) { | |
// Cache exists. Send the response. | |
res.send(reply); | |
} else { | |
// Use the Universal engine to render a response. | |
next(); | |
} | |
}); | |
// Middleware to render a response using the Universal engine | |
const universalRenderer: express.RequestHandler = (req, res) => { | |
res.render( | |
indexHtml, | |
{ | |
req, | |
providers: [{ provide: APP_BASE_HREF, useValue: req.baseUrl }], | |
}, | |
(error: Error, html: string) => { | |
if (error) { | |
return req.next(error); | |
} | |
if (res.statusCode === 200) { | |
// Cache the rendered HTML | |
redisClient.set(cacheKey(req), html); | |
} | |
res.send(html); | |
} | |
); | |
}; | |
// Serve static files from dist/browser | |
server.get( | |
'*.*', | |
express.static(distFolder, { | |
maxAge: '1y', | |
}) | |
); | |
// All regular routes use the Universal engine | |
server.get('*', cachedResponse, universalRenderer); | |
return server; | |
} | |
function run() { | |
const port = process.env.PORT || 4000; | |
// Start up the Node server | |
const server = app(); | |
server.listen(port, () => { | |
console.log(`Node Express server listening on http://localhost:${port}`); | |
}); | |
} | |
// Webpack will replace 'require' with '__webpack_require__' | |
// '__non_webpack_require__' is a proxy to Node 'require' | |
// The below code is to ensure that the server is run only when not requiring the bundle. | |
declare const __non_webpack_require__: NodeRequire; | |
const mainModule = __non_webpack_require__.main; | |
const moduleFilename = mainModule && mainModule.filename || ''; | |
if (moduleFilename === __filename || moduleFilename.includes('iisnode')) { | |
run(); | |
} | |
export * from './src/main.server'; |
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follow: https://www.newline.co/courses/newline-guide-to-angular-universal/redis-middleware