* Throw error if res is accessed after gSSP returns
Currently it's possible to access the `ServerResponse` through `context.res`
in `getServerSideProps()`. If one was to store that response and mutate
its headers or status code after gSSP returns (e.g. during rendering), it
would currently happen to work because of when headers are sent. However,
this is an anti-pattern that relies an implementation detail of the framework
and shouldn't be allowed. This will be particularly important once Next.js
starts to support basic streaming (two-part flush: routing then data) because
then the headers will be sent as soon as gSSP returns, which explicitly breaks
this pattern.
With this commit, the framework now throws an error in development mode if
the ServerResponse is accessed after gSSP returns.
* fixup! Throw error if res is accessed after gSSP returns
Use `Writable` instead of `Observable` and remove the `zen-observable` dependencies. I initially opted to use `Observable` for simplicity and fast iteration, but we should really just use `Writable` directly (or some other stream in the future).
React's streaming SSR has some [specific requirements](https://github.com/reactwg/react-18/discussions/66#discussioncomment-944266) on the stream API. Rather than trying to also squeeze a `Readable` in here, which might be more standard for node apps, I've just followed React's lead. By limiting ourselves to just `Writable`, it ought to be easier to adopt a different stream type in the future if desired.
The React `pipeToNodeWritable` API requires us to pass a stream immediately, but we don't actually have a `ServerResponse` to give it until `RenderResult.pipe(...)` is called later. For that reason, we pass React a `Writable` that we will simply forward to `res` later. This mechanism of deferring is `NodeWritablePiper`, which is just a function that can be called with `ServerResponse` (or another `Writable`, as we now do to render to string for static results) to have content written to it. `NodeWritablePiper` takes a `next` argument so that we can chain both synchronous and asynchronous pipers together.
Also does some clean up and adds another streaming test for backpressure.
This ensures we have the correct `cache-control` header when `revalidate` is used with `notFound: true` on `getStaticProps` or `getServerSideProps` pages.
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Errors have helpful link attached, see `contributing.md`
Fixes: https://app.clubhouse.io/vercel/story/23445
We're no longer currently planning on supporting caching for dynamic responses, so we can do some cleaning & simplification:
* Multiplexing can be removed since we only ever subscribe once (via `RenderResult.pipe`, described below)
* `RenderResult.toUnchunkedString` can become synchronous since static responses are never chunked
* `RenderResult.forEach` can become `RenderResult.pipe` which helps encapsulate some of the details of `RenderResult`
Updates the React 18 concurrent tests to support streaming, by using webdriver (instead of cheerio) to support dynamic updates, and being more explicit about SSR vs. hydrated content.
Also enables streaming support by setting `supportsDynamicHTML: true` in `pipe(...)` for non-bot user agents.
Previous to this change, getServerSideProps could only return plain objects
for props, e.g.:
```javascript
export async function getServerSideProps() {
return {
props: {
text: 'some value',
}
}
}
```
With this commit, the props object can also be a Promise, e.g.
```javascript
export async function getServerSideProps() {
return {
props: (async function () {
return {
text: 'promise value',
}
})(),
}
}
```
For now, the framework simply waits for the results of the props Promise to resolve,
but this small change sets the groundwork for later allowing props to be streamed (cc @devknoll).
## Feature
- [x] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR. -- *This is part of @devknoll's ongoing work to support streaming.*
- [ ] 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. *not sure if this applies here*
- [ ] Errors have helpful link attached, see `contributing.md`
This ensures we handle 204 and 304 status codes correctly in API routes.
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Errors have helpful link attached, see `contributing.md`
Fixes: https://github.com/vercel/next.js/issues/28464
This is similar to https://github.com/vercel/next.js/pull/27126 , https://github.com/vercel/next.js/pull/27446 and https://github.com/vercel/next.js/pull/27974
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] 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`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [x] Make sure the linting passes
This is a follow-up to https://github.com/vercel/next.js/pull/28227 to ensure `_app` and `_document` HMR correctly when you start the dev server and then add `_app` and `_document`.
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Errors have helpful link attached, see `contributing.md`
x-ref: https://github.com/vercel/next.js/issues/27888
Our `Observable` use has gotten sufficiently complex that it makes sense to just use a 3rd party implementation and not worry about maintaining it ourselves. As a bonus, it doesn't rely on Node APIs.
This adds a proper error when we fail to load a user's `next.config.js` as the default node error can be confusing on its own and makes it seem like something failed internally in Next.js. We can expand on the included error doc added and potentially also add better syntax errors by parsing with acorn when we fail to load this file in the future.
<details>
<summary>screenshot</summary>
<img width="962" alt="Screen Shot 2021-08-13 at 21 46 09" src="https://user-images.githubusercontent.com/22380829/129432211-6d858062-eea0-4bb9-8725-5bde98bdc47b.png">
</details>
This fixes revalidation not occurring correctly when `notFound: true` is returned during build, additional tests have been added to ensure this is working correctly for dynamic and non-dynamic pages returning `notFound: true` during build and then revalidating afterwards.
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Errors have helpful link attached, see `contributing.md`
Fixes: https://github.com/vercel/next.js/issues/21453
Implements `renderToString` in terms of a new `renderToStream`. The former is used for legacy documents that generate the body HTML as part of `getInitialProps`. The latter will be used directly in #27794 when streaming dynamic HTML.
Since we're exposing an actual streaming response for dynamic HTML (instead of buffering with `resultFromChunks`), we use `multiplexResult` to buffer and multiplex the underlying result to multiple subscribers.
We generate the HTML for a document in two steps: First, we generate the body (i.e. everything under `<div id="__next">`). Then we generate the rest of the document and embed the body in it.
This doesn't work when the body is a stream, because React can't render the body for us unless we buffer it, and buffering it means not streaming. This PR takes the existing approach for AMP and uses it for all scenarios: instead of rendering HTML, we just render a placeholder that we can replace with HTML later. This will be used in a follow-up PR to let us know where to concatenate the body stream.
I also used the opportunity to split out `HtmlContext` from `DocumentProps`, as these will not be the same thing with functional document components.
This PR adds the `poweredByHeader` and `webpack` fields to the public `NextConfig` type.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] 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`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes
Allows opting in to support for new concurrent features, like server-side Suspense.
**!!! DO NOT USE !!!**
This is highly experimental. We **will** be gating additional breaking changes behind this same flag.
**!!! DO NOT USE !!!**
Also resolves suspense for static pages (i.e. `getStaticProps` or `next build`/`next export`) since we can't currently support streaming for those cases anyway.
Remove unnecessary `React.Suspense` checks, as the minimum supported version is `react@>=17.0.1`. Also removes some files from the `react-18` integration test that are no longer necessary as of #26664.
fixes#27210
maybe related: #19668
currently, the image optimizer returns 400 when an image url contains non-ascii characters. this pr uri-encodes the `url` query parameter to fix it. also see https://github.com/vercel/next.js/issues/27210#issuecomment-890305204
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] 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`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] 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`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes
In this PR I've added the `Content-Disposition` header to the response of the image `/_next/image` route. That header is used by the browser when showing the dialog for the `Save image as...` action.
There are some differences between the browsers, ex:
When requesting the image `test.jpg`, the response header `Content-Type: image/webp` - in FF the filename from the `Save image as...` dialog would be `test.webp` but in Chrome `test.jpg` even if the `Content-Disposition: inline; filename="test.webp"` is present in the headers. The same about png images, the rest types are fine. It looks like FF is checking the `Content-Type` for the extension but the Chrome does not and is doing another type of check.
Fixes#26737
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [x] Make sure the linting passes
Adds `RenderResult`, replacing the `string` that `renderToHTML` used to return, with an `Observable`-like API that callers can use to subscribe and get a callback when chunks are available to flush, etc.
This is the last architectural change needed for streaming. There are, however, other things currently standing in the way of streaming. For example, it is common to mutate `res` in `getServerSideProps` to do routing work, or write headers, before fetching page data. This pattern effectively nullifies any advantages of streaming. I may do a follow-up PR that adds an experimental alternative for applications not using React 18, but the main purpose for this support is for Suspense and Server Components.
For that reason, there's no actual streaming here yet: instead we just flush a single chunk. A follow-up PR will add support for streaming suspense boundaries in React 18.
