Simple Backend-For-Frontend server

[!WARNING]
It's fine if you use this library from NPM package with a static versioning in case you want it for some pet-project or to test it's capabilities.

But for production use it's strongly recommended to create a fork, because I do not write Changelogs and may break / add some functionality without notice.

Extensible BFF server based on Express that handles static and security.

Features

• Handles static resources with Brotli/Gzip support (should be generated by bundler)
• Supports security rules
• Supports HTTPS (locally) / HTTP protocols
• Supports async template modifications for SSR
• Restricts cache for HTML template
• Can respond with versionIdentifier using GET /get-app-version for notifying users when new version is released
• Handles 404 errors
• Gathers performance metrics that could be injected in template

Usage

1. Create file ex. ./server.ts

import path from 'path';

import { runServer } from 'dk-bff-server';

import { env } from '../env';
import { paths } from '../paths';

void runServer({
  port: env.EXPRESS_PORT, // number
  https: env.HTTPS_BY_NODE, // boolean
  templatePath: path.resolve(paths.build, 'template.html'), // path string
  staticFilesPath: paths.build, // path string
  versionIdentifier: env.GIT_COMMIT, // string
  compressedFilesGenerated: env.GENERATE_COMPRESSED, // boolean
  templateModifier: ({ template }) => {
    return Promise.resolve(
      template
        .replace(
          '<!-- HOST_DEPENDENT_CONFIG -->',
          JSON.stringify({
            API_HOST: env.API_HOST,
            IMAGE_STORAGE_URL: env.IMAGE_STORAGE_URL,
          })
        )
    );
  },
  injectMeasures: ({ template, measures }) =>
    template.replace('<!-- MEASURES -->', JSON.stringify({ server: measures }, null, 2)),
  
  customMiddlewares: [
    (app) => {
      // your middlewares
      // app.use(cookieParser());
    }
  ],

  /**
   * @docs: https://github.com/helmetjs/helmet
   * @docs: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
   */

  helmetOptions: {
    contentSecurityPolicy: {
      directives: {},
    }
  },
});

2. Build via you bundler
3. Start using recipe in package.json, ex.

{
  "scripts": {
    "start": "node -r dotenv/config ./build/server.js"
  }
}