This PR introduces [Edge Runtime](https://edge-runtime.vercel.app/) for emulating [Edge Functions](https://vercel.com/features/edge-functions) locally.
Every time you run a [middleware](https://nextjs.org/docs/advanced-features/middleware) locally via `next dev`, an isolated edge runtime context will be created.
These contexts have the same constraints as production servers, plus they don't pollute the global scope; Instead, all the code run in a vm on top of a Node.js process.
Additionally, `@edge-runtime/jest-environment` has been added to make easier testing Edge Functions in a programmatic way.
It dropped the following polyfills from Next.js codebase, since they are now part of Edge Runtime:
- abort-controller
- formdata
- uuid
- web-crypto
- web-streams
Co-authored-by: Gal Schlezinger <2054772+Schniz@users.noreply.github.com>
_Hello Next.js team! First PR here, I hope I've followed the right practices._
### What's in there?
It has been decided to only support the following uses cases in Next.js' middleware:
- rewrite the URL (`x-middleware-rewrite` response header)
- redirect to another URL (`Location` response header)
- pass on to the next piece in the request pipeline (`x-middleware-next` response header)
1. during development, a warning on console tells developers when they are returning a response (either with `Response` or `NextResponse`).
2. at build time, this warning becomes an error.
3. at run time, returning a response body will trigger a 500 HTTP error with a JSON payload containing the detailed error.
All returned/thrown errors contain a link to the documentation.
This is a breaking feature compared to the _beta_ middleware implementation, and also removes `NextResponse.json()` which makes no sense any more.
### How to try it?
- runtime behavior: `HEADLESS=true yarn jest test/integration/middleware/core`
- build behavior : `yarn jest test/integration/middleware/build-errors`
- development behavior: `HEADLESS=true yarn jest test/development/middleware-warnings`
### Notes to reviewers
The limitation happens in next's web adapter. ~The initial implementation was to check `response.body` existence, but it turns out [`Response.redirect()`](https://github.com/vercel/next.js/blob/canary/packages/next/server/web/spec-compliant/response.ts#L42-L53) may set the response body (https://github.com/vercel/next.js/pull/31886). Hence why the proposed implementation specifically looks at response headers.~
`Response.redirect()` and `NextResponse.redirect()` do not need to include the final location in their body: it is handled by next server https://github.com/vercel/next.js/blob/canary/packages/next/server/next-server.ts#L1142
Because this is a breaking change, I had to adjust several tests cases, previously returning JSON/stream/text bodies. When relevant, these middlewares are returning data using response headers.
About DevEx: relying on AST analysis to detect forbidden use cases is not as good as running the code.
Such cases are easy to detect:
```js
new Response('a text value')
new Response(JSON.stringify({ /* whatever */ })
```
But these are false-positive cases:
```js
function returnNull() { return null }
new Response(returnNull())
function doesNothing() {}
new Response(doesNothing())
```
However, I see no good reasons to let users ship middleware such as the one above, hence why the build will fail, even if _technically speaking_, they are not setting the response body.
## 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.
- [x] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [x] Make sure the linting passes by running `yarn lint`
Hello,
This is an iteration after first work at https://github.com/vercel/next.js/pull/36478.
What that PR missed is a way to just get a cookie value. Well, this PR adds two new things:
`cookies.get` returns the cookie value that could be `string | undefined`:
```js
const response = new NextResponse()
response.cookies.set('foo', 'bar', { path: '/test' })
const value = response.cookies.get('foo')
console.log(value) // => 'bar'
```
Additionally, if you want to know all the cookie details, you can use `cookies.getWithOptions`:
```js
const response = new NextResponse()
response.cookies.set('foo', 'bar', { path: '/test' })
const { value, options } response.cookies.getWithOptions('foo')
console.log(value) // => 'bar'
console.log(options) // => { Path: '/test' }
```
This PR introduces a more predictable API to manipulate cookies in an Edge Function context.
```js
const response = new NextResponse()
// set a cookie
response.cookies.set('foo, 'bar') // => set-cookie: 'foo=bar; Path=/'`
// set another cookie
response.cookies.set('fooz, 'barz') // => set-cookie: 'foo=bar; Path=/, fooz=barz; Path=/'`
// delete a cookie means mark it as expired
response.cookies.delete('foo') // => set-cookie: 'foo=; Path=/; Expires=Thu, 01 Jan 1970 00:00:00 GMT, fooz=barz; Path=/'`
// clear all cookies means mark all of them as expired
response.cookies.clear() // => set-cookie: 'fooz=; Path=/; Expires=Thu, 01 Jan 1970 00:00:00 GMT, foo=; Path=/; Expires=Thu, 01 Jan 1970 00:00:00 GMT'`
```
This new cookies API uses [Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) interface, and it's available for `NextRequest` and `NextResponse`.
Additionally, you can pass a specific cookies option as a third argument in `set` method:
```js
response.cookies.set('foo', 'bar', {
path: '/',
maxAge: 60 * 60 * 24 * 7,
httpOnly: true,
sameSite: 'strict',
domain: 'example.com'
}
```
**Note**: `maxAge` it's in seconds rather than milliseconds.
Any cookie manipulation will be reflected over the `set-cookie` header, transparently.
closes#31719
