Fast Angular Universal SSR server example with Redis, compression, map "security" (for curious developers) and API proxy endpoint

server.ts

import 'zone.js/node';
import 'dotenv/config';
import '@ng-web-apis/universal/mocks';

import { ngExpressEngine } from '@nguniversal/express-engine';
import * as express from 'express';
import { join } from 'path';

import { AppServerModule } from './src/main.server';
import { APP_BASE_HREF } from '@angular/common';
import { existsSync, readFileSync } from 'fs';
import { renderModule } from '@angular/platform-server';
import { enableProdMode, LOCALE_ID } from '@angular/core';

import * as url   from 'url';
import * as proxy from 'express-http-proxy';

import * as Redis from 'ioredis';
import * as compression from 'shrink-ray-current';

// const dotenv = require('dotenv');
// dotenv.config();
// console.log('process.env: ', process.env);

enableProdMode();

const distFolder = join(process.cwd(), 'dist/myproject/browser');
const indexFile = existsSync(join(distFolder, 'index.original.html')) ? 'index.original.html' : 'index.html';
const indexHtml = readFileSync(join(distFolder, indexFile), 'utf-8').toString();

const useRedisCache = process.env['USE_REDIS'] === 'true';
let redisClient: Redis.Redis;
if(useRedisCache) {
  redisClient = new Redis({
      port    : parseInt(process.env['REDIS_PORT'] ?? '6379', 10),
      host    : process.env['REDIS_HOST'] || 'localhost',
      username: process.env['REDIS_USR']  || 'default',
      password: process.env['REDIS_PWD']  || 'docker',
      db: 0,
    });
}

function execRenderModule(renderUrl: string, res: express.Response, req: express.Request, useRedisCache: boolean) {
  renderModule(AppServerModule, {
    document: indexHtml,
    url: renderUrl,
    extraProviders: [ 
      { provide: APP_BASE_HREF, useValue: req.baseUrl },
      {provide: LOCALE_ID, useValue: 'es-CL'} 
    ]
  })
  .then(html => {
    if(useRedisCache) {
      redisClient.set(renderUrl, html, (err: any, result: any) => {
        if(err) {
          console.error('Error setting Redis cache: ', err);
        }
        if(result) {
          console.log('Set Redis cache: ', renderUrl);
        }
      });
    }

    res.setHeader("Content-Type", "text/html")
    res.status(200).send(html);
  })
  .catch(err => {
      console.error(err);
      res.sendStatus(500);
  });
}

// The Express app is exported so that it can be used by serverless Functions.
export function app() {
  const server = express();

  // Our Universal express-engine (found @ https://github.com/angular/universal/tree/master/modules/express-engine)
  server.engine('html', ngExpressEngine({
    bootstrap: AppServerModule,
  }));

  server.set('view engine', 'html');
  server.set('views', distFolder);

  server.set('etag', 'strong');
  server.set('x-powered-by', false);

  server.use(
    compression({
      cache: () => true,
      zlib: {
          level: 2
      },
      brotli: {
          quality: 4
      }
    } as any)
  );

//   // TODO: implement data requests securely
//   server.get('/api/**', (req, res) => {
//     res.status(404).send('data requests are not yet supported');
//   });
  console.log('SSR proxy:', 'http://localhost:' + (process.env['API_PORT'] || 3000)  + '/api')
  const ssrProxyHost = 'http://localhost:' + (process.env['API_PORT'] || 3000);
  server.use('/api/*', (proxy as any)(ssrProxyHost, {
    proxyReqPathResolver: (req: any): string | null => {
          const targetUrl = url.parse(req.baseUrl).path;
          console.log('SSR proxy:', req.originalUrl, targetUrl);
          return targetUrl as string;
      }
  }));
  server.use('/img/*', (proxy as any)(ssrProxyHost, {
    proxyReqPathResolver: (req: any): string | null => {
          const targetUrl = url.parse(req.baseUrl).path;
          console.log('SSR proxy:', req.originalUrl, targetUrl);
          return targetUrl as string;
      }
  }));

  // Endpoint para la captura de las peticiones sobre archivos de extension .map que pueden eventualmente no existir
  server.route(/(.*)\.(css|js)\.map$/).get((req, res, next) => {
    console.log(`[${new Date().toISOString()}] - [${req.method}] - [${req.url}]: Curioso tratando de  debuguear un archivo .map desde ${req.headers['cf-connecting-ip'] || req.headers['x-forwarded-for'] || req.connection.remoteAddress}`);
    res.status(200).json({ version: 3, file: `${req.url || req.originalUrl}`, sources: [], names: [], mappings: [] });
  });

  // Serve static files from /browser
  server.get('*.*', express.static(distFolder, {
    maxAge: '1y'
  }));

  // All regular routes use the Universal engine
  server.get('*', (req, res) => {
    console.log('GET *: ', req.url);
    // res.setHeader("Content-Type", "text/html");
    // res.render(indexFile, { req, res, providers: [{ provide: APP_BASE_HREF, useValue: req.baseUrl }] });
    const renderUrl: string = req.url;
    console.log('Rendering SSR: ', renderUrl);
    if(useRedisCache) {
      const _cache = redisClient.get(renderUrl, (err: any, result: any) => {
        if(err) {
          console.log('Error getting Redis cache: ', err);
        }
        if(result) {
          console.log('Got Redis cache: ', renderUrl);
          res.setHeader("Content-Type", "text/html");
          res.status(200).send(result);
        } else {
          console.log('No Redis cache: ', renderUrl);
          execRenderModule(renderUrl, res, req, useRedisCache);
        }
      });
    }
    
    
  });

  return server;
}

function run() {
  const port = process.env['SSR_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';