nitro-conditional-middleware

Development

install

npm install

test

npm run test

lint

npm run lint:fix

build

npm run build

Documentation

A brief explanation on how middlewares in nitrojs work.

NitroJS provides as base for their middlewares H3 event handlers created by defineEventHandler.

Middlewares in the nitrojs framework are executed in every request.

Real life scenarios

In this diagram we display 3 different scenarios that our server needs to handle:

• Open API requests
• Authenticated API requests
• HealthCheck Requests

Problem

Knowing that all events will pass through all middlewares, we need to plan the flow based on conditions that will run or skip these middlewares

Skipping middlewares

With the constrain that the event flow will pass through all middleware event handlers, we needed a way to skip a middleware for some events that will go through the middleware pipeline based on a particular condition.

This library creates a way to pass a condition as parameter to create defineMiddlewareHandler functions with a run condition. This function has the same signature as as H3's defineEventHandler. Making it a 1:1 substitute.

type condition = (event: H3Event) => boolean

// This function would return a handler as H3's `defineEventHandler`
const defineMiddlewareHandler = createMiddlewareHandler(condition)

Creating and using multiple middlewareHandlers

// defineApiMiddleware.ts
import { createMiddlewareHandler } from 'nitro-conditional-middleware'

const apiV1MiddlewareHandler = createMiddlewareHandler((event) => {
  return event.path.includes('/api/v1/')
})

const apiV2ConditionFn = (event: H3Event) => boolean {
  return event.path.includes('/api/v2/')
}

const apiV2MiddlewareHandler = createMiddlewareHandler(apiV2ConditionFn)

// usage 1.my-first-middleware.ts
import { apiV1MiddlewareHandler } from './defineApiMiddleware'

const myFirstMiddleware = (event) => {
  console.log('myFirstMiddleware: This will only run in api/v1 endpoints')
}

export default apiV1MiddlewareHandler(myFirstMiddleware)

// usage 2.my-second-middleware.ts
import { apiV2MiddlewareHandler } from './defineApiMiddleware'

export default apiV2MiddlewareHandler((event) => {
  console.log('mySecondMiddleware: This will only run in api/v2 endpoints')
})