765791a6d1
This PR adds a feature in middleware to add, modify, or delete request headers. This feature is quite useful to pass data from middleware to Serverless/Edge API routes. ### Questions for Reviewers - Should we deny modifying standard request headers like `Transfer-Encoding`? - Should we throw an error if the header is too large? Real-world HTTP servers will accept up to only 8KB - 32KB. ### New APIs Adds a new option `request.headers` to the `MiddlewareResponseInit` parameter in `NextResponse.next()` and `NextResponse.rewrite()`. It's a [`Header`](https://developer.mozilla.org/en-US/docs/Web/API/Headers) object holding *all* request headers. Specifically: ```ts interface MiddlewareResponseInit extends ResponseInit { request?: { headers?: Headers } } ``` ### Example ```ts // pages/api/hello.ts export default (req, res) => { const valueFromMiddleware = req.headers['x-hello-from-middleware'] return res.send(valueFromMiddleware) } // middleware.ts import { NextRequest, NextResponse } from 'next/server' export default function middleware(request: NextRequest) { // Clone request headers const headers = new Headers(request.headers); // Add a new request header headers.set('x-hello-from-middleware', 'foo'); // Delete a request header from the client headers.delete('x-from-client'); const resp = NextResponse.next({ // New option `request.headers` which accepts a Headers object // overrides request headers with the specified new ones. request: { headers } }); // You can still set *response* headers to the client, as before. resp.headers.set('x-hello-client', 'bar'); return resp; } ``` ### New middleware headers - `x-middleware-override-headers`: A comma separated list of *all* request header names. Headers not listed will be deleted. - `x-middleware-request-<name>`: A new value for the header `<name>`. ## Related Discussions - https://github.com/vercel/next.js/discussions/31188 - https://github.com/vercel/next.js/discussions/39300 ## Bug - [ ] Related issues linked using `fixes #number` - [ ] Integration tests added - [ ] Errors have a helpful link attached, see `contributing.md` ## Feature - [x] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR. - [ ] Related issues linked using `fixes #number` - [x] Integration tests added - [x] Documentation added - [ ] Telemetry added. In case of a feature if it's used or not. - [ ] Errors have a helpful link attached, see `contributing.md` ## Documentation / Examples - [ ] Make sure the linting passes by running `pnpm lint` - [ ] The "examples guidelines" are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md) |
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sandbox | ||
spec-extension | ||
adapter.ts | ||
error.ts | ||
next-url.ts | ||
types.ts | ||
utils.ts |