mirror of
https://github.com/storytold/effectcraft.git
synced 2026-10-30 13:08:07 -06:00
G.J.R. Timmer
df9207d1be
An explicit demo startup no longer saves the session, so the demo cannot replace the last visit's project. The config request is aborted after 5 s, stops reading once the body passes the size limit, and is skipped for ?empty and ?demo. The packaged hosting notes link to the published docs.
74 lines
3.0 KiB
Rust
74 lines
3.0 KiB
Rust
//! `./effectcraft-config.json`, fetched once per page load and shared by whoever reads a key.
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use std::cell::RefCell;
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use wasm_bindgen::{JsCast, closure::Closure};
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use wasm_bindgen_futures::JsFuture;
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use crate::startup::{self, Startup};
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/// Longest the request and the body read may take (ms); a stalled server must not hold up start-up.
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const TIMEOUT_MS: i32 = 5_000;
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thread_local! {
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/// `None`: not fetched yet; `Some(None)`: no usable file.
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static FILE: RefCell<Option<Option<Vec<u8>>>> = const { RefCell::new(None) };
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}
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/// The config file's bytes, or `None` when it is missing, too large, unreadable or the request
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/// takes longer than [`TIMEOUT_MS`] (the timer aborts the request and covers the body read).
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async fn fetch() -> Option<Vec<u8>> {
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let win = web_sys::window()?;
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let ctl = web_sys::AbortController::new().ok()?;
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let init = web_sys::RequestInit::new();
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// Always ask the server: the file is the operator's switch, never a cached copy.
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init.set_cache(web_sys::RequestCache::NoCache);
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init.set_signal(Some(&ctl.signal()));
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let on_timeout = Closure::once(move || ctl.abort());
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let timer = win.set_timeout_with_callback_and_timeout_and_arguments_0(on_timeout.as_ref().unchecked_ref(), TIMEOUT_MS).ok()?;
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let out = read(&win, &init).await;
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win.clear_timeout_with_handle(timer);
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out
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}
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/// Fetch the file and read its body chunk by chunk, giving up as soon as it passes `CONFIG_MAX`.
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async fn read(win: &web_sys::Window, init: &web_sys::RequestInit) -> Option<Vec<u8>> {
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let req = web_sys::Request::new_with_str_and_init("effectcraft-config.json", init).ok()?;
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let resp: web_sys::Response = JsFuture::from(win.fetch_with_request(&req)).await.ok()?.dyn_into().ok()?;
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if resp.status() != 200 {
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return None;
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}
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let reader: web_sys::ReadableStreamDefaultReader = resp.body()?.get_reader().unchecked_into();
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let mut out = Vec::new();
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loop {
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let chunk = JsFuture::from(reader.read()).await.ok()?;
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if js_sys::Reflect::get(&chunk, &"done".into()).ok()?.as_bool() == Some(true) {
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return Some(out);
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}
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let bytes: js_sys::Uint8Array = js_sys::Reflect::get(&chunk, &"value".into()).ok()?.dyn_into().ok()?;
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if out.len().saturating_add(bytes.length() as usize) > startup::CONFIG_MAX {
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// Stop the download: the limit is enforced while reading, not after the whole body arrived.
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let _ = reader.cancel();
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return None;
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}
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out.extend_from_slice(&bytes.to_vec());
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}
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}
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/// The config file's bytes (`None` when there is none), fetched on the first call.
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pub async fn bytes() -> Option<Vec<u8>> {
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if let Some(done) = FILE.with(|f| f.borrow().clone()) {
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return done;
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}
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let got = fetch().await;
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FILE.with(|f| *f.borrow_mut() = Some(got.clone()));
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got
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}
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/// The configured startup behaviour.
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pub async fn startup() -> Startup {
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let s = bytes().await.map(|b| startup::parse(&b)).unwrap_or_default();
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log::info!("startup: {s:?}");
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s
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}
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