50 lines
1.6 KiB
JavaScript
50 lines
1.6 KiB
JavaScript
import { readFile, writeFile, mkdir } from "node:fs/promises";
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import { parseWord, PARSER_VERSION } from "./parser.js";
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import { request, MIN_REFRESH } from "./source.js";
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import { DATA } from "./paths.js";
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const data = DATA + "parsed/";
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// When each document was last downloaded, and the downloads under way: a forced refresh
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// downloads a document at most once per MIN_REFRESH, and simultaneous ones share a download.
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const fetchedAt = new Map(),
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loading = new Map();
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/** A parsed catalog document, from the disk cache while the file and parser are unchanged. */
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export async function scheduleFor(file, { refresh = false } = {}) {
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const cache = data + file.id + ".json";
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if (refresh && Date.now() - (fetchedAt.get(file.id) || 0) < MIN_REFRESH) refresh = false;
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if (!refresh)
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try {
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const cached = JSON.parse(await readFile(cache, "utf8"));
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if (
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cached.schemaVersion === PARSER_VERSION &&
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cached.source.modified === file.modified
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)
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return cached;
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} catch {}
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if (!loading.has(file.id))
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loading.set(
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file.id,
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download(file, cache).finally(() => loading.delete(file.id)),
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);
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return loading.get(file.id);
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}
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async function download(file, cache) {
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const buffer = await request(file.path);
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fetchedAt.set(file.id, Date.now());
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const parsed = await parseWord(buffer, {
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name: file.name,
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url: file.url,
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faculty: file.faculty,
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modified: file.modified,
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fileId: file.id,
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form: file.form,
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course: file.course,
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year: file.year,
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});
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await mkdir(data, { recursive: true });
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await writeFile(cache, JSON.stringify(parsed));
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return parsed;
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}
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