Chad Kimes (Feb 20 2024 at 22:15): Chad Kimes (Feb 20 2024 at 22:15):Hi! I'm poking at ComponentizeJS and trying to figure out how to explicitly drop a resource. I have this code targeting WASI preview 2 HTTP working in Rust:
if let Some(body) = body {
let req_body = req.body().expect("getting body");
let stream = req_body.write().expect("getting body");
stream.blocking_write_and_flush(body).expect("writing content");
drop(stream);
OutgoingBody::finish(req_body, None).expect("finishing body");
}
As per the WIT definitions, dropping the writer is necessary before calling OutgoingBody::finish:
resource outgoing-body {
/// Returns a stream for writing the body contents.
///
/// The returned `output-stream` is a child resource: it must be dropped
/// before the parent `outgoing-body` resource is dropped (or finished),
/// otherwise the `outgoing-body` drop or `finish` will trap.
///
/// Returns success on the first call: the `output-stream` resource for
/// this `outgoing-body` may be retrieved at most once. Subsequent calls
/// will return error.
write: func() -> result<output-stream>;
However I can't figure out how to cause the drop to execute in JS:
if (body) {
let reqBody = req.body();
let stream = reqBody.write();
stream.blockingWriteAndFlush(body);
stream.drop(); // TypeError: stream.drop is not a function
OutgoingBody.finish(reqBody);
}
I know that I'm mostly on the right path, since GET methods work but my POSTs with a body are failing. Eliding the drop altogether results in the documented trap when calling OutgoingBody.finish. How can I force this stream to be dropped?
Guy Bedford (Feb 20 2024 at 22:25):You can use stream[Symbol.for('dispose')](); to do the dispose from JS
Chad Kimes (Feb 20 2024 at 22:25):And of course 5 minutes after posting that I find: https://github.com/bytecodealliance/ComponentizeJS/blob/89ac2c5730866ebe47afaf3a8ae231c59761796e/test/cases/resource-borrow-import/source.js#L3
I had tried with Symbol.dispose previously and that didn't work, so apparently the magic was Symbol.for('dispose')
Guy Bedford (Feb 20 2024 at 22:25):When Spidermonkey supports Symbol.dispose we will switch to that
Guy Bedford (Feb 20 2024 at 22:25):so then it will be the new using syntax eventually
Guy Bedford (Feb 20 2024 at 22:26):we should better document this though certainly
Chad Kimes (Feb 20 2024 at 22:26):Right, and I suppose if I had adopted typescript's using then I wouldn't have seen this at all
Chad Kimes (Feb 20 2024 at 22:32):While you're active - is there a recommended bundler for joining multiple JS files together? I just want to unclutter my main file by putting some helpers somewhere else, but naive concat quickly runs into import collisions
Chad Kimes (Feb 20 2024 at 22:32):preferably something invokeable from the mjs file
Guy Bedford (Feb 20 2024 at 22:46):Note it's still Symbol.for('dispose') instead of Symbol.dispose. We could directly define Symbol.dispose = Symbol.for('dispose') to make this easier I suppose, posted https://github.com/bytecodealliance/ComponentizeJS/pull/81. For bundling modules, esbuild / swc / rollup are all good.
Chad Kimes (Feb 20 2024 at 22:53):oh nice! that looks great
Notification Bot (Feb 20 2024 at 23:06):Chad Kimes has marked this topic as resolved.
Last updated: Oct 23 2024 at 20:03 UTC