githubmirror/next.js

errors/nested-middleware.mdx

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Delba de Oliveira

docs: Migrate error messages to MDX and App Router. (#52038)

05 июл 2023, 16:11

05 июл 2023, 16:1144d1a1c

---
title: Nested Middleware
---

## Why This Error Occurred

You are defining a Middleware file in a location different from `<root>/middleware`, which is not allowed.

While in beta, a Middleware file under specific pages would _only_ be executed when pages below its declaration were matched, allowing nesting Middleware files. Based on customer feedback, we have replaced this API with a single root Middleware.

## Possible Ways to Fix It

Declare your Middleware in the root folder and use `NextRequest` parsed URL to define which path the Middleware should be executed for.

For example, a Middleware at `pages/about/_middleware.ts` can move the logic to `<root>/middleware.ts` in the root of your repository. Then, a conditional statement can be used to only run the Middleware when it matches the `about/*` path:

```ts filename="middleware.ts"
import type { NextRequest } from 'next/server'

export function middleware(request: NextRequest) {
  if (request.nextUrl.pathname.startsWith('/about')) {
    // This logic is only applied to /about
  }

  if (request.nextUrl.pathname.startsWith('/dashboard')) {
    // This logic is only applied to /dashboard
  }
}
```

If you have more than one Middleware, you should combine them into a single file and model their execution depending on the incoming request.