Routing: Route Handlers | Next.js

Inhalt

Route Handlers allow you to create custom request handlers for a given route using the Web Request and Response APIs.

Route.js Special FileRoute.js Special File

Good to know: Route Handlers are only available inside the app directory. They are the equivalent of API Routes inside the pages directory meaning you do not need to use API Routes and Route Handlers together.

Convention

Route Handlers are defined in a route.js|ts file inside the app directory:

export const dynamic = 'force-dynamic' // defaults to auto
export async function GET(request: Request) {}

Route Handlers can be nested inside the app directory, similar to page.js and layout.js. But there cannot be a route.js file at the same route segment level as page.js.

Supported HTTP Methods

The following HTTP methods are supported: GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS. If an unsupported method is called, Next.js will return a 405 Method Not Allowed response.

Extended NextRequest and NextResponse APIs

In addition to supporting native Request and Response. Next.js extends them withNextRequest and NextResponse to provide convenient helpers for advanced use cases.

Behavior

Caching

Route Handlers are cached by default when using the GET method with the Response object.

export async function GET() {
  const res = await fetch('https://data.mongodb-api.com/...', {
    headers: {
      'Content-Type': 'application/json',
      'API-Key': process.env.DATA_API_KEY,
    },
  })
  const data = await res.json()

return Response.json({ data }) }

TypeScript Warning: Response.json() is only valid from TypeScript 5.2. If you use a lower TypeScript version, you can use NextResponse.json() for typed responses instead.

Opting out of caching

You can opt out of caching by:

For example:

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url)
  const id = searchParams.get('id')
  const res = await fetch(`https://data.mongodb-api.com/product/${id}`, {
    headers: {
      'Content-Type': 'application/json',
      'API-Key': process.env.DATA_API_KEY!,
    },
  })
  const product = await res.json()

return Response.json({ product }) }

Similarly, the POST method will cause the Route Handler to be evaluated dynamically.

export async function POST() {
  const res = await fetch('https://data.mongodb-api.com/...', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'API-Key': process.env.DATA_API_KEY!,
    },
    body: JSON.stringify({ time: new Date().toISOString() }),
  })

const data = await res.json()

return Response.json(data) }

Good to know: Like API Routes, Route Handlers can be used for cases like handling form submissions. A new abstraction for handling forms and mutations that integrates deeply with React is being worked on.

Route Resolution

You can consider a route the lowest level routing primitive.

  • They do not participate in layouts or client-side navigations like page.
  • There cannot be a route.js file at the same route as page.js.

| Page | Route | Result | | -------------------- | ---------------- | -------- | | app/page.js | app/route.js | Conflict | | app/page.js | app/api/route.js | Valid | | app/[user]/page.js | app/api/route.js | Valid |

Each route.js or page.js file takes over all HTTP verbs for that route.

export default function Page() {
  return <h1>Hello, Next.js!</h1>
}

// ❌ Conflict // app/route.js export async function POST(request) {}

Examples

The following examples show how to combine Route Handlers with other Next.js APIs and features.

Revalidating Cached Data

You can revalidate cached data using the next.revalidate option:

export async function GET() {
  const res = await fetch('https://data.mongodb-api.com/...', {
    next: { revalidate: 60 }, // Revalidate every 60 seconds
  })
  const data = await res.json()

return Response.json(data) }

Alternatively, you can use the revalidate segment config option:

export const revalidate = 60

Dynamic Functions

Route Handlers can be used with dynamic functions from Next.js, like cookies and headers.

Cookies

You can read or set cookies with cookies from next/headers. This server function can be called directly in a Route Handler, or nested inside of another function.

Alternatively, you can return a new Response using the Set-Cookie header.

import { cookies } from 'next/headers'

export async function GET(request: Request) { const cookieStore = cookies() const token = cookieStore.get('token')

return new Response('Hello, Next.js!', { status: 200, headers: { 'Set-Cookie': token=${token.value} }, }) }

You can also use the underlying Web APIs to read cookies from the request (NextRequest):

import { type NextRequest } from 'next/server'

export async function GET(request: NextRequest) { const token = request.cookies.get('token') }

You can read headers with headers from next/headers. This server function can be called directly in a Route Handler, or nested inside of another function.

This headers instance is read-only. To set headers, you need to return a new Response with new headers.

import { headers } from 'next/headers'

export async function GET(request: Request) { const headersList = headers() const referer = headersList.get('referer')

return new Response('Hello, Next.js!', { status: 200, headers: { referer: referer }, }) }

You can also use the underlying Web APIs to read headers from the request (NextRequest):

import { type NextRequest } from 'next/server'

export async function GET(request: NextRequest) { const requestHeaders = new Headers(request.headers) }

Redirects 

import { redirect } from 'next/navigation'

export async function GET(request: Request) { redirect('https://nextjs.org/') }

Dynamic Route Segments

We recommend reading the Defining Routes page before continuing.

Route Handlers can use Dynamic Segments to create request handlers from dynamic data.

export async function GET(
  request: Request,
  { params }: { params: { slug: string } }
) {
  const slug = params.slug // 'a', 'b', or 'c'
}

| Route | Example URL | params | | --------------------------- | ----------- | ------------- | | app/items/[slug]/route.js | /items/a | { slug: 'a' } | | app/items/[slug]/route.js | /items/b | { slug: 'b' } | | app/items/[slug]/route.js | /items/c | { slug: 'c' } |

URL Query Parameters

The request object passed to the Route Handler is a NextRequest instance, which has some additional convenience methods, including for more easily handling query parameters.

import { type NextRequest } from 'next/server'

export function GET(request: NextRequest) { const searchParams = request.nextUrl.searchParams const query = searchParams.get('query') // query is "hello" for /api/search?query=hello }

Streaming

Streaming is commonly used in combination with Large Language Models (LLMs), such as OpenAI, for AI-generated content. Learn more about the AI SDK.

import OpenAI from 'openai'
import { OpenAIStream, StreamingTextResponse } from 'ai'

const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY, })

export const runtime = 'edge'

export async function POST(req: Request) { const { messages } = await req.json() const response = await openai.chat.completions.create({ model: 'gpt-3.5-turbo', stream: true, messages, })

const stream = OpenAIStream(response)

return new StreamingTextResponse(stream) }

These abstractions use the Web APIs to create a stream. You can also use the underlying Web APIs directly.

// https://developer.mozilla.org/docs/Web/API/ReadableStream#convert_async_iterator_to_stream
function iteratorToStream(iterator: any) {
  return new ReadableStream({
    async pull(controller) {
      const { value, done } = await iterator.next()

  if (done) {
    controller.close()
  } else {
    controller.enqueue(value)
  }
},

}) }

function sleep(time: number) { return new Promise((resolve) => { setTimeout(resolve, time) }) }

const encoder = new TextEncoder()

async function* makeIterator() { yield encoder.encode('<p>One</p>') await sleep(200) yield encoder.encode('<p>Two</p>') await sleep(200) yield encoder.encode('<p>Three</p>') }

export async function GET() { const iterator = makeIterator() const stream = iteratorToStream(iterator)

return new Response(stream) }

Request Body

You can read the Request body using the standard Web API methods:

export async function POST(request: Request) {
  const res = await request.json()
  return Response.json({ res })
}

Request Body FormData

You can read the FormData using the request.formData() function:

export async function POST(request: Request) {
  const formData = await request.formData()
  const name = formData.get('name')
  const email = formData.get('email')
  return Response.json({ name, email })
}

Since formData data are all strings, you may want to use zod-form-data to validate the request and retrieve data in the format you prefer (e.g. number).

CORS

You can set CORS headers for a specific Route Handler using the standard Web API methods:

export const dynamic = 'force-dynamic' // defaults to auto

export async function GET(request: Request) { return new Response('Hello, Next.js!', { status: 200, headers: { 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Methods': 'GET, POST, PUT, DELETE, OPTIONS', 'Access-Control-Allow-Headers': 'Content-Type, Authorization', }, }) }

Good to know:

Webhooks

You can use a Route Handler to receive webhooks from third-party services:

export async function POST(request: Request) {
  try {
    const text = await request.text()
    // Process the webhook payload
  } catch (error) {
    return new Response(`Webhook error: ${error.message}`, {
      status: 400,
    })
  }

return new Response('Success!', { status: 200, }) }

Notably, unlike API Routes with the Pages Router, you do not need to use bodyParser to use any additional configuration.

Edge and Node.js Runtimes

Route Handlers have an isomorphic Web API to support both Edge and Node.js runtimes seamlessly, including support for streaming. Since Route Handlers use the same route segment configuration as Pages and Layouts, they support long-awaited features like general-purpose statically regenerated Route Handlers.

You can use the runtime segment config option to specify the runtime:

export const runtime = 'edge' // 'nodejs' is the default

Non-UI Responses

You can use Route Handlers to return non-UI content. Note that sitemap.xml, robots.txt, app icons, and open graph images all have built-in support.

export const dynamic = 'force-dynamic' // defaults to auto

export async function GET() { return new Response( `<?xml version="1.0" encoding="UTF-8" ?> <rss version="2.0">

<channel> <title>Next.js Documentation</title> <link>https://nextjs.org/docs</link> <description>The React Framework for the Web</description> </channel>

</rss>`, { headers: { 'Content-Type': 'text/xml', }, } ) }

Segment Config Options

Route Handlers use the same route segment configuration as pages and layouts.

export const dynamic = 'auto'
export const dynamicParams = true
export const revalidate = false
export const fetchCache = 'auto'
export const runtime = 'nodejs'
export const preferredRegion = 'auto'

See the API reference for more details.

Verknüpfung
https://nextjs.org/docs/app/building-your-application/routing/route-handlers
Zusammenfassen
Route Handlers in Next.js allow for custom request handlers for specific routes using the Web Request and Response APIs. They are defined in a route.js|ts file inside the app directory and support HTTP methods such as GET, POST, PUT, PATCH, DELETE, HEAD, and OPTIONS. Route Handlers can be cached by default when using the GET method with the Response object, but caching can be opted out of using the Request object, other HTTP methods, dynamic functions, or segment config options. Examples of using Route Handlers with caching, revalidating cached data, dynamic functions, redirects, dynamic route segments, and URL query parameters are provided.