Understanding the Basics

Before diving deep into the process of custom server configurations, it's crucial to understand why this is vital. A custom server in NextJS allows you to start a server to handle requests instead of the default NextJS server. This functionality becomes essential when you want to include existing express/connect middlewares or integrate with other servers like Go, PHP, etc.

This process provides enhanced flexibility and adaptability, which is invaluable in managing more complex applications.

Setting up a custom server in NextJS is simple, leveraging the flexibility of JavaScript and the power of Express.js.

```javascript

const express = require('express')

const next = require('next')

const dev = process.env.NODE_ENV !== 'production'

const app = next({ dev })

const handle = app.getRequestHandler()

app.prepare()

.then(() => { const server = express() server.get('/a', (req, res) => { return app.render(req, res, '/b', req.query) }) server.get('/b', (req, res) => { return app.render(req, res, '/a', req.query) }) server.get('*', (req, res) => { return handle(req, res) }) server.listen(3000, (err) => { if (err) throw err console.log('> Ready on http://localhost:3000') }) }) .catch((ex) => { console.error(ex.stack) process.exit(1) }) ```

Note: We use express in the example, but you can replace it with any other server framework that can handle http requests.

Delving Deeper into Custom Server Configurations

As we move into more complex custom server configurations, we can see how we can better leverage NextJS's built-in features, such as dynamic routes and automatic static optimization.

The crucial point to remember is that NextJS generates and optimizes many things automatically, such as pages in the `/pages` folder becoming routes automatically. Still, the introduction of a custom server will disable this automatic static file serving.

This behavior facilitates an environment where you can create more complex configurations using NextJS's built-in Router. Additionally, it also allows for server-side rendering and server-side loading data.

Here's a basic example of a route with data fetching. It can be useful for scenarios like search engine optimization (SEO), where you want to display essential information in the HTML that is sent from the server.

```javascript

server.get('/post/:id', (req, res) => {

const actualPage = '/post' const queryParams = { id: req.params.id } app.render(req, res, actualPage, queryParams) }) ```

On the other hand, with server-side rendering, you can generate the return response on the server. This process involves receiving a request, fetching the necessary data, and rendering the page to HTML.

```javascript

server.get('/post/:id', async (req, res) => {

const post = await getPostData(req.params.id) res.send( `Hello World! Post: ${post.title}` ) }) ```

Wrap Up

Custom server configuration in NextJS has its advantages and complexities, but overall, it's an extremely powerful feature that can take your web application to another level. With the knowledge of how to create and manage these configurations efficiently, you can significantly enhance your project's flexibility and functionality.

Before we end this guide, we'd like to introduce you to PullTheCode, a NextJS boilerplate designed to streamline your development process. It provides essential features like SEO & blog integration, Stripe payments, SQL with Prisma, SSO with PassportJS, Google Analytics, etc. It's targeted towards developers and startups aiming to launch their MVPs quickly and efficiently.

PullTheCode also offers weekly updates and specific modules like the Scraping module or in-progress Internationalization module, to keep up with evolving web app development needs. It’s an ideal solution to harness the full potential of NextJS without the hassle of setting up everything from scratch. Explore PullTheCode today to take your NextJS development to the next level.