mirror of
https://github.com/mauriceboe/TREK.git
synced 2026-11-13 15:51:00 +00:00
John Jahn
04b1fb72bb
Every file under assets/ was compressed again on each download, at the low level a request path can afford. They carry their content hash in the name and never change, so the client build now writes a Brotli copy beside each compressible one (postbuild, scripts/precompress.mjs) and production points a browser that accepts Brotli at that copy before express.static serves it. Measured on a production build of 5.1.2, fetching the 652 precached files the way a service worker install does: 16.3 MB -> 13.9 MB on the wire and about 1.0 s -> 0.2 s of server CPU per install. A client without Brotli, a range request and a build without copies are served exactly as before.
61 lines
2.2 KiB
JavaScript
61 lines
2.2 KiB
JavaScript
/*
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* The work behind scripts/precompress.mjs: a Brotli copy (<file>.br) beside every
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* compressible build file under dist/assets.
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*
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* The server compresses a build file on every download otherwise, at the low level
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* a request path can afford. A file under assets/ carries its content hash in its
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* name and never changes, so it is compressed once here, at the level a build can
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* afford, and the server hands that copy out as it is
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* (server/src/nest/platform/precompressed-static.ts).
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*/
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import { readdirSync, readFileSync, writeFileSync } from 'node:fs';
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import { join } from 'node:path';
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import { brotliCompressSync, constants } from 'node:zlib';
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/** What the server's own compression would take; fonts, images and video are compressed formats already. */
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const COMPRESSIBLE = /\.(?:m?js|css|svg|json|wasm|html|webmanifest)$/i;
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/** The server leaves anything below 1 kB uncompressed too: the headers cost more than the saving. */
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export const MIN_BYTES = 1024;
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/** Quality 11 takes about ten times as long per byte as 9, so the largest chunks get 9. */
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const BIG_BYTES = 1024 * 1024;
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function* walk(dir) {
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for (const entry of readdirSync(dir, { withFileTypes: true })) {
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const full = join(dir, entry.name);
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if (entry.isDirectory()) yield* walk(full);
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else yield full;
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}
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}
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/**
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* Writes the .br copies under `dir` and returns what it did. A copy that would not be
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* smaller than its file is not written, and a directory that does not exist is no work.
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*/
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export function precompress(dir) {
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const result = { files: 0, before: 0, after: 0 };
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let files;
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try {
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files = [...walk(dir)];
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} catch (err) {
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if (err.code === 'ENOENT') return result;
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throw err;
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}
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for (const file of files) {
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if (!COMPRESSIBLE.test(file)) continue;
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const input = readFileSync(file);
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if (input.length < MIN_BYTES) continue;
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const output = brotliCompressSync(input, {
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params: {
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[constants.BROTLI_PARAM_QUALITY]: input.length > BIG_BYTES ? 9 : 11,
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[constants.BROTLI_PARAM_SIZE_HINT]: input.length,
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},
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});
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if (output.length >= input.length) continue;
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writeFileSync(`${file}.br`, output);
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result.files += 1;
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result.before += input.length;
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result.after += output.length;
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}
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return result;
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}
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