express-bff

An Express middleware for simple way to create BFF (backend-for-frontend) server for your RIA/SPA applications.

Features

• Automated client-side security.
• Built-in sessions.
• File-based REST API controllers with automatic route-matching.
• Server-sent event (SSE) support out-of-the-box.
• Automated proxying of requests to backend server.
• Easy integration with Server-side rendering (SSR) engines.
• Static files serving if needed.
• Query to SQL (QSQL) support. (coming soon)
• Memoization of response based on request params. (coming soon)
• GrapthQL integration. (coming soon)
• Websockets support. (coming soon)

Install

npm i express-bff --save

Usage

Configuration

const path = require('path');
const express = require('express');
const bff = require('express-bff');

const app = express();

bff(app, {
    security: {
        cors: false,
        secure,
    },
    session: {
        persist: true,
        // OR
        persist({ secret, ttl }) {
          return new CustomStore();
        }
    },
    sse: {
        path: '/events',
        // option serializer callback for objects
        serializer(key, val) {
          return val;
        }
    },
    api: {
        dir: path.join(__dirname, 'routes'),
    },
    proxy: {
        target: 'https://192.x.x.x:3030',
    },
    static: {
        dir: path.join(__dirname, 'static'),
        single: true,
        dev,
    },
    ssr: {
      template: 'index', // provide template name for express render engine
      handler(req) {
        return { /* any locals to render in template */ };
      }
    }
});

app.listen(process.env.PORT);

REST API controller

// ./routes/posts/index.js => /posts

module.exports = {
    get,
    post,
    patch,
    put,
    delete: del
};

async function get(req, res) {
  // ...
}

async function post(req, res) {
  // ...
}

async function put(req, res) {
  // ...
}

async function patch(req, res) {
  // ...
}

async function del(req, res) {
  // ...
}

Route with dynamic parameters:

// ./routes/posts/:id.js => /posts/:id

module.exports = {
    get,
    ...
};

async function get(req, res) {
  console.log('ID is ', req.params.id);
}

Changelog

1.1.0

• Improve SSR support, including support of Express template engines for SSR.
• Add typings.
• Update deps.
• New serializer option is added to sse middleware.