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https://github.com/vercel/next.js.git
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Justin Ridgewell
31d2b720d9
### What?
This reimplements our stream cancellation code for a few more cases:
1. Adds support in all stream-returning APIs
2. Fixes cancellation detection in node 16
3. Implements out-of-band detection, so can cancel in the middle of a
read
It also (finally) adds tests for all the cases I'm aware of.
### Why?
To allow disconnecting from an AI service when a client disconnects. $$$
### How?
1. Reuses a single pipe function in all paths to push data from the
dev's `ReadableStream` into our `ServerResponse`
2. Uses `ServerResponse` to detect disconnect, instead of the
`IncomingMessage` (request)
- The `close` event fire once all incoming body data is read
- The request `abort` event will not fire after the incoming body data
has been fully read
3. Using `on('close')` on the writable destination allows us to detect
close
- Checking for `res.destroyed` in the body of the loop meant we had to
wait for the `await stream.read()` to complete before we could possibly
cancel the stream
- - -
#52157 (and #51594) had an issue with Node 16, because I was using
`res.closed` to detect when the server response was closed by the client
disconnecting. But, `closed` wasn't
[added](https://github.com/nodejs/node/pull/45672) until
[v18.13.0](https://nodejs.org/en/blog/release/v18.13.0#:~:text=%5Bcbd710bbf4%5D%20%2D%20http%3A%20make%20OutgoingMessage%20more%20streamlike%20(Robert%20Nagy)%20%2345672).
This fixes it by using `res.destroyed`.
Reverts #52277
Relands #52157
Fixes #52809
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32 lines
658 B
TypeScript
32 lines
658 B
TypeScript
import * as stream from 'stream'
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import { Deferred, sleep } from './sleep'
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export function Readable(write: number) {
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const encoder = new TextEncoder()
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const cleanedUp = new Deferred()
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const aborted = new Deferred()
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let i = 0
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const readable = {
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finished: Promise.all([cleanedUp.promise, aborted.promise]).then(() => i),
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abort() {
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aborted.resolve()
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},
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stream: new stream.Readable({
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async read() {
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if (i >= write) {
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return
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}
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await sleep(100)
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this.push(encoder.encode(String(i++)))
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},
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destroy() {
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cleanedUp.resolve()
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},
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}),
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}
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return readable
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}
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