fe797c1074
Internal suggestion to remove `en-US` from Mozilla urls since MDN is available in multiple languages nowadays it will automatically redirect to the viewer’s language preference. Closes [DX-2076](https://linear.app/vercel/issue/DX-2076/make-external-mozilla-links-language-agnostic-in-nextjs-docs)
40 lines
1.6 KiB
Text
40 lines
1.6 KiB
Text
---
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title: Middleware Relative URLs
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---
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## Why This Error Occurred
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You are using a Middleware function that uses `Response.redirect(url)`, `NextResponse.redirect(url)` or `NextResponse.rewrite(url)` where `url` is a relative or an invalid URL. Prior to Next.js 12.1, we allowed passing relative URLs. However, constructing a request with `new Request(url)` or running `fetch(url)` when `url` is a relative URL **does not** work. For this reason and to bring consistency to Next.js Middleware, this behavior has been deprecated and now removed.
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## Possible Ways to Fix It
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To fix this error you must always pass absolute URL for redirecting and rewriting. There are several ways to get the absolute URL but the recommended way is to clone `NextURL` and mutate it:
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```ts filename="middleware.ts"
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import type { NextRequest } from 'next/server'
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import { NextResponse } from 'next/server'
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export function middleware(request: NextRequest) {
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const url = request.nextUrl.clone()
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url.pathname = '/dest'
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return NextResponse.rewrite(url)
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}
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```
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Another way to fix this error could be to use the original URL as the base but this will not consider configuration like `basePath` or `locale`:
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```ts filename="middleware.ts"
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import type { NextRequest } from 'next/server'
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import { NextResponse } from 'next/server'
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export function middleware(request: NextRequest) {
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return NextResponse.rewrite(new URL('/dest', request.url))
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}
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```
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You can also pass directly a string containing a valid absolute URL.
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## Useful Links
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- [URL Documentation](https://developer.mozilla.org/docs/Web/API/URL)
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- [Response Documentation](https://developer.mozilla.org/docs/Web/API/Response)
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