265 lines
9.8 KiB
JavaScript
265 lines
9.8 KiB
JavaScript
// server/http/files.js — one file on disk → an HTTP response (static.js and media.js decide which file):
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// MIME types incl. .mjs/.js text/javascript, .skel application/octet-stream, .atlas text/plain;
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// gzip for text-like types, .skel and uncompressed fonts when the client accepts it (small files are
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// compressed once and cached in memory); strong ETag + Last-Modified with 304s; Cache-Control
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// (html & code/data: no-cache + revalidate; public/assets|fonts|vendor: 1 day; any `?v=` URL: immutable);
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// single byte-range requests (206/416, used by <audio>).
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import fs from 'node:fs';
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import fsp from 'node:fs/promises';
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import path from 'node:path';
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import zlib from 'node:zlib';
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import { promisify } from 'node:util';
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import { pipeline } from 'node:stream/promises';
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/** Extension → Content-Type. */
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export const MIME = Object.freeze({
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'.html': 'text/html; charset=utf-8',
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'.htm': 'text/html; charset=utf-8',
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'.js': 'text/javascript; charset=utf-8',
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'.mjs': 'text/javascript; charset=utf-8',
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'.css': 'text/css; charset=utf-8',
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'.json': 'application/json; charset=utf-8',
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'.map': 'application/json; charset=utf-8',
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'.webmanifest': 'application/manifest+json; charset=utf-8',
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'.txt': 'text/plain; charset=utf-8',
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'.md': 'text/markdown; charset=utf-8',
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'.csv': 'text/csv; charset=utf-8',
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'.xml': 'application/xml; charset=utf-8',
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'.atlas': 'text/plain; charset=utf-8',
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'.skel': 'application/octet-stream',
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'.bin': 'application/octet-stream',
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'.wasm': 'application/wasm',
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'.png': 'image/png',
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'.jpg': 'image/jpeg',
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'.jpeg': 'image/jpeg',
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'.gif': 'image/gif',
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'.webp': 'image/webp',
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'.avif': 'image/avif',
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'.svg': 'image/svg+xml; charset=utf-8',
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'.ico': 'image/x-icon',
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'.mp3': 'audio/mpeg',
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'.ogg': 'audio/ogg',
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'.oga': 'audio/ogg',
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'.opus': 'audio/ogg',
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'.wav': 'audio/wav',
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'.m4a': 'audio/mp4',
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'.aac': 'audio/aac',
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'.webm': 'video/webm',
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'.mp4': 'video/mp4',
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'.woff2': 'font/woff2',
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'.woff': 'font/woff',
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'.otf': 'font/otf',
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'.ttf': 'font/ttf',
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});
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/** Extensions worth gzipping (text-like, .skel, uncompressed fonts). */
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export const COMPRESSIBLE = new Set([
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'.html', '.htm', '.js', '.mjs', '.css', '.json', '.map', '.webmanifest', '.txt', '.md', '.csv', '.xml',
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'.atlas', '.skel', '.bin', '.wasm', '.svg', '.ico', '.otf', '.ttf', '.wav',
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]);
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const GZIP_MIN_BYTES = 512;
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const GZIP_CACHE_MAX_FILE = 8 << 20; // larger files are gzip-streamed on the fly
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const GZIP_CACHE_MAX_TOTAL = 96 << 20;
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// Asset URLs carry no content hash yet, and tools/fetch-assets.mjs / tools/vendor.mjs can rewrite files in
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// place (atlas + png + skel must stay consistent), so "long" is one day; revalidation after that is a cheap 304.
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export const LONG_CACHE = 'public, max-age=86400'; // 1 day
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export const IMMUTABLE_CACHE = 'public, max-age=31536000, immutable';
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const LONG_CACHE_DIRS = ['assets', 'fonts', 'vendor']; // first path segment under public/
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const gzipAsync = promisify(zlib.gzip);
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// ---------------------------------------------------------------------------------------------------
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// gzip cache (LRU by bytes)
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// ---------------------------------------------------------------------------------------------------
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export class GzipCache {
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constructor(maxTotal = GZIP_CACHE_MAX_TOTAL) {
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this.maxTotal = maxTotal;
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this.total = 0;
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/** @type {Map<string, Buffer>} */ this.map = new Map();
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/** @type {Map<string, Promise<Buffer>>} */ this.inflight = new Map();
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}
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/** @returns {Promise<Buffer>} gzip of the file identified by (path, size, mtime) */
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get(absPath, stat) {
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const key = `${absPath}\0${stat.size}\0${stat.mtimeMs}`;
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const hit = this.map.get(key);
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if (hit) { this.map.delete(key); this.map.set(key, hit); return Promise.resolve(hit); }
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const pending = this.inflight.get(key);
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if (pending) return pending;
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const p = (async () => {
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const raw = await fsp.readFile(absPath);
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const gz = await gzipAsync(raw, { level: 6 });
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this.store(key, gz);
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return gz;
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})().finally(() => this.inflight.delete(key));
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this.inflight.set(key, p);
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return p;
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}
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store(key, buf) {
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if (buf.length > this.maxTotal) return;
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this.map.set(key, buf);
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this.total += buf.length;
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for (const [k, v] of this.map) {
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if (this.total <= this.maxTotal) break;
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this.map.delete(k);
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this.total -= v.length;
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}
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}
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}
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// ---------------------------------------------------------------------------------------------------
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// HTTP helpers
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// ---------------------------------------------------------------------------------------------------
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/** Does the Accept-Encoding header allow gzip (q > 0)? @param {string | undefined} header */
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export function acceptsGzip(header) {
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if (!header || typeof header !== 'string') return false;
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let gzipQ = null;
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let starQ = null;
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for (const part of header.split(',')) {
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const [token, ...params] = part.trim().toLowerCase().split(';');
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let q = 1;
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for (const p of params) {
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const m = /^\s*q=([0-9.]+)\s*$/.exec(p);
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if (m) q = Number(m[1]);
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}
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if (!Number.isFinite(q)) q = 0;
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if (token === 'gzip' || token === 'x-gzip') gzipQ = q;
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else if (token === '*') starQ = q;
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}
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if (gzipQ != null) return gzipQ > 0;
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return starQ != null && starQ > 0;
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}
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/**
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* Parse a single `bytes=` range against a file size.
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* @returns {{ start: number, end: number } | 'unsatisfiable' | null} null = ignore header (serve 200)
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*/
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export function parseRange(header, size) {
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if (typeof header !== 'string') return null;
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const m = /^\s*bytes\s*=\s*(\d*)\s*-\s*(\d*)\s*$/i.exec(header);
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if (!m) return null; // multi-range or malformed → ignore (RFC 9110 permits serving the full body)
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const [, a, b] = m;
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if (a === '' && b === '') return null;
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if (a === '') {
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const suffix = Number(b);
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if (suffix === 0 || size === 0) return 'unsatisfiable';
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return { start: Math.max(0, size - suffix), end: size - 1 };
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}
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const start = Number(a);
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const end = b === '' ? size - 1 : Math.min(Number(b), size - 1);
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if (b !== '' && Number(b) < start) return null;
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if (start >= size) return 'unsatisfiable';
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return { start, end };
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}
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const stripWeak = (tag) => tag.trim().replace(/^W\//, '');
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/** Conditional GET check (If-None-Match wins over If-Modified-Since). */
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export function isNotModified(req, etag, mtime) {
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const inm = req.headers['if-none-match'];
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if (typeof inm === 'string') {
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if (inm.trim() === '*') return true;
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return inm.split(',').some((t) => stripWeak(t) === etag);
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}
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const ims = req.headers['if-modified-since'];
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if (typeof ims === 'string') {
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const t = Date.parse(ims);
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if (Number.isFinite(t)) return Math.floor(mtime.getTime() / 1000) * 1000 <= t;
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}
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return false;
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}
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/** If-Range: serve the range only when the validator still matches. */
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function ifRangeMatches(req, etag, lastModified) {
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const v = req.headers['if-range'];
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if (typeof v !== 'string') return true;
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const s = v.trim();
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if (s.startsWith('"') || s.startsWith('W/')) return s === etag; // strong comparison
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return s === lastModified;
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}
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function cacheControlFor(ext, mountName, segments, query) {
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if (ext === '.html' || ext === '.htm') return 'no-cache';
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if (/(^|&)v=/.test(query)) return IMMUTABLE_CACHE;
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if (mountName === 'public' && segments.length > 1 && LONG_CACHE_DIRS.includes(segments[0])) return LONG_CACHE;
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return 'no-cache';
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}
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export async function serveFile(req, res, absPath, stat, mountName, segments, query, gzipCache, log) {
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const ext = path.extname(absPath).toLowerCase();
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const type = MIME[ext] || 'application/octet-stream';
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const compressible = COMPRESSIBLE.has(ext);
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const rangeHeader = req.headers.range;
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const useGzip = compressible && stat.size >= GZIP_MIN_BYTES && !rangeHeader && acceptsGzip(req.headers['accept-encoding']);
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const baseTag = `${stat.size.toString(16)}-${Math.floor(stat.mtimeMs).toString(16)}`;
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const etag = `"${baseTag}${useGzip ? '-gz' : ''}"`;
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const lastModified = stat.mtime.toUTCString();
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const isHead = req.method === 'HEAD';
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const headers = {
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'Content-Type': type,
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'Cache-Control': cacheControlFor(ext, mountName, segments, query),
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ETag: etag,
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'Last-Modified': lastModified,
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};
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if (compressible) headers.Vary = 'Accept-Encoding';
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if (isNotModified(req, etag, stat.mtime)) {
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res.writeHead(304, headers);
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res.end();
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return;
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}
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if (useGzip) {
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headers['Content-Encoding'] = 'gzip';
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if (stat.size <= GZIP_CACHE_MAX_FILE) {
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const gz = await gzipCache.get(absPath, stat);
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headers['Content-Length'] = gz.length;
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res.writeHead(200, headers);
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res.end(isHead ? undefined : gz);
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return;
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}
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res.writeHead(200, headers);
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if (isHead) { res.end(); return; }
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await streamTo(fs.createReadStream(absPath), res, log, zlib.createGzip());
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return;
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}
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headers['Accept-Ranges'] = 'bytes';
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let start = 0;
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let end = stat.size - 1;
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let status = 200;
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if (rangeHeader && ifRangeMatches(req, etag, lastModified)) {
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const r = parseRange(rangeHeader, stat.size);
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if (r === 'unsatisfiable') {
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res.writeHead(416, { 'Content-Range': `bytes */${stat.size}`, 'Content-Type': 'text/plain; charset=utf-8', 'Content-Length': 0 });
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res.end();
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return;
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}
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if (r) {
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({ start, end } = r);
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status = 206;
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headers['Content-Range'] = `bytes ${start}-${end}/${stat.size}`;
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}
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}
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headers['Content-Length'] = stat.size === 0 ? 0 : end - start + 1;
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res.writeHead(status, headers);
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if (isHead || stat.size === 0) { res.end(); return; }
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await streamTo(fs.createReadStream(absPath, { start, end }), res, log);
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}
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async function streamTo(src, res, log, transform) {
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try {
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if (transform) await pipeline(src, transform, res);
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else await pipeline(src, res);
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} catch (e) {
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if (e && e.code !== 'ERR_STREAM_PREMATURE_CLOSE') log.debug?.('[http] stream aborted', e.code || e.message);
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res.destroy();
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}
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}
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