Deno.serve's fast streaming implementation was not keeping the request
body resource ID alive. We were taking the `Rc<Resource>` from the
resource table during the response, so a hairpin duplex response that
fed back the request body would work.
However, if any JS code attempted to read from the request body (which
requires the resource ID to be valid), the response would fail with a
difficult-to-diagnose "EOF" error.
This was affecting more complex duplex uses of `Deno.fetch` (though as
far as I can tell was unreported).
Simple test:
```ts
const reader = request.body.getReader();
return new Response(
new ReadableStream({
async pull(controller) {
const { done, value } = await reader.read();
if (done) {
controller.close();
} else {
controller.enqueue(value);
}
},
}),
```
And then attempt to use the stream in duplex mode:
```ts
async function testDuplex(
reader: ReadableStreamDefaultReader<Uint8Array>,
writable: WritableStreamDefaultWriter<Uint8Array>,
) {
await writable.write(new Uint8Array([1]));
const chunk1 = await reader.read();
assert(!chunk1.done);
assertEquals(chunk1.value, new Uint8Array([1]));
await writable.write(new Uint8Array([2]));
const chunk2 = await reader.read();
assert(!chunk2.done);
assertEquals(chunk2.value, new Uint8Array([2]));
await writable.close();
const chunk3 = await reader.read();
assert(chunk3.done);
}
```
In older versions of Deno, this would just lock up. I believe after
23ff0e722e, it started throwing a more
explicit error:
```
httpServerStreamDuplexJavascript => ./cli/tests/unit/serve_test.ts:1339:6
error: TypeError: request or response body error: error reading a body from connection: Connection reset by peer (os error 54)
at async Object.pull (ext:deno_web/06_streams.js:810:27)
```
Fixes #19737 by adding brotli compression parameters.
Time after:
`Accept-Encoding: gzip`:
```
real 0m0.214s
user 0m0.005s
sys 0m0.013s
```
`Accept-Encoding: br`:
Before:
```
real 0m10.303s
user 0m0.005s
sys 0m0.010s
```
After:
```
real 0m0.127s
user 0m0.006s
sys 0m0.014s
```
Fixes for various `Attemped to access invalid request` bugs (#19058,
#15427, #17213).
We did not wait for both a drop event and a completion event before
removing items from the slab table. This ensures that we do so.
In addition, the slab methods are refactored out into `slab.rs` for
maintainability.
`Content-Encoding: gzip` support for `Deno.serve`. This doesn't support
Brotli (`br`) yet, however it should not be difficult to add. Heuristics
for compression are modelled after those in `Deno.serveHttp`.
Tests are provided to ensure that the gzip compression is correct. We
chunk a number of different streams (zeros, hard-to-compress data,
already-gzipped data) in a number of different ways (regular, random,
large/small, small/large).
This is a rewrite of the `Deno.serve` API to live on top of hyper
1.0-rc3. The code should be more maintainable long-term, and avoids some
of the slower mpsc patterns that made the older code less efficient than
it could have been.
Missing features:
- `upgradeHttp` and `upgradeHttpRaw` (`upgradeWebSocket` is available,
however).
- Automatic compression is unavailable on responses.
