What this is about

This package exports some common Next.js API middleware patterns that you might need across different applications. It aims to provide useful and mostly flexible drop-in functions.

What is included

• Authorization: Basic, Bearer (JWT), Custom
• Route Guarding: Make sure certain fields are present in the request
• RESTify Your Routes: A simple function allowing you to map different handlers to http methods
• Error Catching: Wrap your handlers with a convenient error handling middleware

If you have something in mind that is generally help- or useful and is not included in this list, please feel free to open an issue.

Getting Started

Installation

Yarn

yarn add nextjs-api-common-middleware

NPM

npm install --save nextjs-api-common-middleware

Configuration

While generally not required, it is recommended that you re-export the middleware collection with your own default configuration.

Create a file called middleware.js/middleware.ts somewhere that suits you well, the contents of the file should look something like this:

import { createExport } from 'nextjs-api-common-middleware';

const m = createExport({
    catch: (_req, res, err) => {
        console.error(err);
        res.status(500).send('An unknown error occurred');
    },
    auth: {
        strategy: 'custom',
        custom: (authHeaderValue, _req) => {
            if (authHeaderValue && authHeaderValue === 'test') {
                return {
                    uid: 123,
                    user: {
                        firstname: 'Test',
                        lastname: 'User',
                    },
                };
            }
            return null;
        },
    },
});

export default m;

Usage

Basic Example

// src/pages/api/hello.js
import m from '../../middleware'; // or 'nextjs-api-common-middleware'

async function handler(req, res) {
    res.json({ hello: 'world' });
}

export default m.auth(handler); // second argument could be additional options

Chaining Middleware

// src/pages/api/hello.js
import m from '../../middleware'; // or 'nextjs-api-common-middleware'

async function handler(req, res) {
    res.json({ hello: 'world' });
}

export default m._.chain([m.auth, m.guard], handler, {
    // auth options are still remembered from the initial configuration
    guard: {
        required: ['foo'],
    },
});