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Monorepo for Aesthetic.Computer aesthetic.computer
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JavaScript
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Saved enabled is// consent history, never restart authorization. No heartbeat: server TTL applies.import { mkdir, readFile, writeFile, rename, lstat, realpath, rm,} from "node:fs/promises";import { resolve, join, relative, dirname } from "node:path";import { createHash, randomBytes } from "node:crypto";import { SITE, USER_AGENT } from "./ac-session.mjs";import { decode } from "../media/picture/png.mjs";import { verifyROM } from "../media/gameboy/rom.mjs";const MAX = 8 * 1024 * 1024;const MIMES = { picture: ["image/png", "image/jpeg", "image/webp"], sound: ["audio/wav", "audio/mpeg", "audio/ogg"], paper: ["application/pdf", "text/plain"], gameboy: ["application/x-gameboy-rom", "text/plain"],};const sha = (b) => createHash("sha256").update(b).digest("hex");const sleep = (ms) => new Promise((resolve) => setTimeout(resolve, ms));async function safe(base, path) { const target = resolve(base, path), rel = relative(base, target); if (rel === ".." || rel.startsWith("../")) throw new Error("Broadcast path leaves workspace."); let cursor = base; for (const part of ["", ...rel.split("/")]) { if (part) cursor = join(cursor, part); try { if ((await lstat(cursor)).isSymbolicLink()) throw new Error("Broadcast paths cannot contain symlinks."); } catch (e) { if (e.code !== "ENOENT") throw e; } } return target;}async function bounded(file, max) { const stat = await lstat(file); if (!stat.isFile() || stat.size < 1 || stat.size > max) throw new Error( `Broadcast file must be a regular file under ${max} bytes.`, ); const data = await readFile(file); if (!data.length || data.length > max) throw new Error("Broadcast file changed size while reading."); return data;}function validRecord(record, owner, artifactId, kind) { if ( !record || record.owner !== owner || record.artifactId !== artifactId || record.kind !== kind || !/^[a-f0-9]{32}$/.test(record.id) || !Number.isSafeInteger(record.sequence) || record.sequence < 0 ) throw new Error("Invalid account-bound broadcast record."); return record;}export class DraftBroadcast { constructor({ cwd, session, fetch = globalThis.fetch, site = SITE, onState = () => {}, timeoutMs = 20000, } = {}) { this.cwd = resolve(cwd || process.cwd()); this.session = session; this.fetch = fetch; this.site = site.replace(/\/$/, ""); this.onState = onState; this.timeoutMs = timeoutMs; this.channels = new Map(); this.queue = new Set(); this.pumping = null; this.transport = Promise.resolve(); this.closed = false; this.nextUpload = 0; this.timers = new Set(); } wait(ms) { if (this.closed || ms <= 0) return Promise.resolve(); return new Promise((resolve) => { const item = { resolve, timer: null }; item.timer = setTimeout(() => { this.timers.delete(item); resolve(); }, ms); this.timers.add(item); }); } account() { const owner = this.session?.read?.()?.user?.sub, handle = this.session?.handle; if (typeof owner !== "string" || !owner || !handle) throw new Error("Sign in with an AC @handle before broadcasting."); return { owner, handle }; } async channel({ artifactId, kind }) { if (!MIMES[kind]) throw new Error( "Broadcast Picture, Sound, Paper or Game Boy output; Piece uses its existing live path.", ); if (!/^[a-f0-9-]{36}$/.test(artifactId || "")) throw new Error("Invalid broadcast artifact identity."); const { owner, handle } = this.account(), key = sha(`${owner}\0${kind}\0${artifactId}`); if (this.channels.has(key)) return this.channels.get(key); const base = await realpath(this.cwd), file = await safe(base, `.easel/broadcasts/${key}.json`); let record = null; try { record = validRecord( JSON.parse(await bounded(file, 65536)), owner, artifactId, kind, ); } catch (e) { if (e.code !== "ENOENT") throw e; } const channel = { key, file, owner, handle, artifactId, kind, record, authorized: false, active: false, pending: null, failed: null, waiters: [], epoch: 0, lastHash: null, controller: null, }; this.channels.set(key, channel); return channel; } async mutate(channel, change) { const base = await realpath(this.cwd); await safe(base, relative(base, dirname(channel.file))); await mkdir(dirname(channel.file), { recursive: true, mode: 0o700 }); const lock = await safe(base, relative(base, channel.file + ".lock")); let locked = false; for (let i = 0; i < 100; i++) { try { await mkdir(lock, { mode: 0o700 }); locked = true; break; } catch (e) { if (e.code !== "EEXIST") throw e; await sleep(20); } } if (!locked) throw new Error("Broadcast record is locked by another operation."); try { let record; try { record = validRecord( JSON.parse(await bounded(channel.file, 65536)), channel.owner, channel.artifactId, channel.kind, ); } catch (e) { if (e.code !== "ENOENT") throw e; record = { format: 1, id: randomBytes(16).toString("hex"), owner: channel.owner, handle: channel.handle, artifactId: channel.artifactId, kind: channel.kind, sequence: 0, enabled: false, }; } change(record); const temp = await safe(base, relative(base, channel.file + ".pending")); await writeFile(temp, JSON.stringify(record) + "\n", { mode: 0o600 }); await rename(temp, channel.file); channel.record = record; return record; } finally { await rm(lock, { recursive: true, force: true }); } } snapshot(channel) { const m = channel.metadata || {}; if (channel.active && m.expiresAt && Date.parse(m.expiresAt) <= Date.now()) channel.active = false; return { id: channel.record?.id || null, enabled: !!channel.record?.enabled, paused: !!channel.record?.paused, active: !!channel.active, route: channel.reserved ? `${this.site}/watch/?id=${channel.record.id}` : channel.active ? m.route || null : null, scanUrl: channel.reserved ? `${this.site}/watch/?id=${channel.record.id}`.replace(/^https:\/\//, "") : channel.active && m.route ? m.route.replace(/^https:\/\//, "") : null, sequence: channel.record?.sequence || 0, version: m.version || null, expiresAt: m.expiresAt || null, artifactId: channel.artifactId, kind: channel.kind, handle: channel.handle, owner: channel.owner, error: channel.error || null, }; } emit(channel) { try { this.onState(this.snapshot(channel)); } catch {} } async current(identity) { if (!this.session?.read?.()?.user?.sub || !this.session?.handle) return { ...identity, id: null, enabled: false, active: false, route: null, scanUrl: null, sequence: 0, expiresAt: null }; return this.snapshot(await this.channel(identity)); } async reserve(identity) { const channel = await this.channel(identity); if (!channel.record) await this.mutate(channel, r => { r.enabled = true; }); channel.reserved = true; return this.snapshot(channel); } async automatic(preview, {kind} = {}) { const identity = {artifactId: preview?.artifactId, kind}; const channel = await this.channel(identity); if (channel.starting) await channel.starting; if (channel.authorized) return this.update(preview, identity); const starting = this.start(preview, identity); channel.starting = starting; try { return await starting; } finally { if (channel.starting === starting) channel.starting = null; } } fresh(channel) { return channel.active && Date.parse(channel.metadata?.expiresAt || '') > Date.now() + 1800000; } async frame(preview, kind) { if (!Number.isSafeInteger(preview?.version) || preview.version < 1) throw new Error("Broadcast preview needs a saved version."); if (!MIMES[kind]?.includes(preview.mime)) throw new Error("Build/render a supported output before broadcasting."); const base = await realpath(this.cwd), versionRoot = await safe( base, `.easel-media/artifacts/${preview.artifactId}/v${preview.version}`, ), file = await safe( versionRoot, relative(versionRoot, resolve(base, relative(this.cwd, resolve(preview.path)))), ); const revision = JSON.parse( await bounded(await safe(versionRoot, "revision.json"), 1024 * 1024), ); const name = relative(versionRoot, file); if ( revision.version !== preview.version || revision.preview?.path !== name || revision.preview?.mime !== preview.mime || !revision.files?.includes(name) ) throw new Error("Preview does not match its saved artifact revision."); if (kind === "gameboy" && revision.sourceAhead) { if (!revision.files?.includes("main.c") || !/^[a-f0-9]{64}$/.test(revision.hashes?.["main.c"] || "")) throw new Error("Game Boy draft needs a declared, hashed main.c source."); const data = await bounded(await safe(versionRoot, "main.c"), MAX); const hash = sha(data); if (hash !== revision.hashes["main.c"]) throw new Error("Broadcast Game Boy source hash mismatch."); return { kind, mime: "text/plain", version: preview.version, hash, data }; } if (revision.sourceAhead) throw new Error( "Build the changed source before broadcasting a new output.", ); const data = await bounded(file, MAX), hash = sha(data); if (revision.hashes?.[name] !== hash) throw new Error("Broadcast preview hash mismatch."); if (preview.mime === "image/png") decode(data); if (preview.mime === "application/x-gameboy-rom") verifyROM(data); if ( preview.mime === "application/pdf" && data.subarray(0, 5).toString() !== "%PDF-" ) throw new Error("Invalid PDF preview."); return { kind, mime: preview.mime, version: preview.version, hash, data }; } async start(preview, { kind } = {}) { if (this.closed) throw new Error("Broadcaster is closed."); const channel = await this.channel({ artifactId: preview?.artifactId, kind, }); const startingEpoch = channel.epoch; const frame = await this.frame(preview, kind); if (this.closed || channel.epoch !== startingEpoch) throw new Error("Broadcast stopped."); await this.mutate(channel, (r) => { r.enabled = true; r.paused = false; r.handle = channel.handle; }); if (this.closed || channel.epoch !== startingEpoch) { await this.mutate(channel, r => { r.enabled = false; }); throw new Error("Broadcast stopped."); } channel.authorized = true; channel.active = false; channel.lastHash = null; channel.epoch++; channel.error = null; return this.enqueue(channel, frame); } async update(preview, { kind } = {}) { if (this.closed) throw new Error("Broadcaster is closed."); const channel = await this.channel({ artifactId: preview?.artifactId, kind, }), epoch = channel.epoch; if (!channel.authorized) throw new Error( "This artifact has not connected yet.", ); const frame = await this.frame(preview, kind); if (epoch !== channel.epoch || !channel.authorized) throw new Error("Broadcast was stopped."); return this.enqueue(channel, frame); } enqueue(channel, frame) { if ( this.fresh(channel) && channel.lastHash === frame.hash && !channel.pending && !channel.inflight ) return Promise.resolve(this.snapshot(channel)); if (channel.latestVersion && frame.version < channel.latestVersion) return Promise.resolve(this.snapshot(channel)); channel.latestVersion = frame.version; channel.pending = frame; channel.failed = null; this.queue.add(channel.key); const pending = new Promise((resolve, reject) => channel.waiters.push({ resolve, reject }), ); this.pump(); return pending; } serialized(work) { const next = this.transport.then(work, work); this.transport = next.catch(() => {}); return next; } pump() { if (this.pumping || this.closed) return; this.pumping = (async () => { while (this.queue.size && !this.closed) { const key = this.queue.values().next().value; this.queue.delete(key); const channel = this.channels.get(key); if (!channel.authorized || !channel.pending) continue; const delay = this.nextUpload - Date.now(); if (delay > 0) await this.wait(delay); if (this.closed || !channel.authorized) continue; const frame = channel.pending; channel.pending = null; if (this.fresh(channel) && channel.lastHash === frame.hash) { for (const waiter of channel.waiters.splice(0)) waiter.resolve(this.snapshot(channel)); continue; } channel.inflight = true; const epoch = channel.epoch; try { const state = await this.serialized(() => this.send(channel, frame, epoch), ); if (channel.authorized && epoch === channel.epoch) { channel.error = null; if (!channel.pending) { const waiters = channel.waiters.splice(0); for (const w of waiters) w.resolve(state); } } } catch (error) { channel.active = false; channel.error = error.message; channel.failed = channel.pending || frame; if (!channel.pending) { const waiters = channel.waiters.splice(0); for (const w of waiters) w.reject(error); } this.emit(channel); } finally { channel.inflight = false; } if (channel.pending && channel.authorized) this.queue.add(key); } })().finally(() => { this.pumping = null; if (this.queue.size && !this.closed) this.pump(); }); } async request(channel, method, payload) { if (method === "POST" && (this.closed || !channel.authorized)) throw new Error("Broadcast stopped."); if (this.account().owner !== channel.owner) throw new Error("AC account changed; broadcast transport stopped."); const token = await this.session.token(); if (this.account().owner !== channel.owner) throw new Error("AC account changed; broadcast transport stopped."); if (method === "POST" && (this.closed || !channel.authorized)) throw new Error("Broadcast stopped."); const controller = new AbortController(); channel.controller = controller; const timer = setTimeout( () => controller.abort(new Error("Broadcast transport timed out.")), this.timeoutMs, ); try { const response = await this.fetch(`${this.site}/api/easel-live`, { method, headers: { Authorization: `Bearer ${token}`, "Content-Type": "application/json", "User-Agent": USER_AGENT, }, body: JSON.stringify(payload), signal: controller.signal, }); const body = await response.json().catch(() => ({})); return { response, body }; } finally { clearTimeout(timer); if (channel.controller === controller) channel.controller = null; } } async send(channel, frame, epoch) { for (let attempt = 0; attempt < 3; attempt++) { if (this.closed || !channel.authorized || channel.epoch !== epoch) throw new Error("Broadcast stopped."); const record = await this.mutate(channel, (r) => { r.sequence = Math.max(r.sequence, channel.serverSequence || 0) + 1; }); this.nextUpload = Date.now() + Math.max(500, (frame.data.length / 262144) * 1000); const { response, body } = await this.request(channel, "POST", { id: record.id, kind: frame.kind, version: frame.version, mime: frame.mime, data: frame.data.toString("base64"), status: "live", sequence: record.sequence, }); if (response.status === 409) { const sequence = body.sequence ?? body.currentSequence; if (!Number.isSafeInteger(sequence) || sequence < 0) throw new Error( "Broadcast sequence was stale; server did not supply its current sequence.", ); channel.serverSequence = sequence; await this.wait(Math.max(0, this.nextUpload - Date.now())); continue; } if (!response.ok) throw new Error( `Broadcast failed (HTTP ${response.status}). The latest frame is retained; reconnecting automatically.`, ); if ( body.id !== record.id || body.sequence !== record.sequence || body.status !== "live" || body.kind !== frame.kind || body.version !== frame.version || body.mime !== frame.mime ) throw new Error("Broadcast server returned mismatched metadata."); let route = null; if (body.route) { const url = new URL(body.route, this.site); if ( url.origin !== new URL(this.site).origin || url.pathname !== "/watch/" || url.searchParams.get("id") !== record.id ) throw new Error( "Broadcast server returned an unexpected viewer route.", ); route = url.href; } if (this.account().owner !== channel.owner) throw new Error("AC account changed; broadcast response discarded."); if (channel.authorized && epoch === channel.epoch) { channel.active = true; channel.error = null; channel.lastHash = frame.hash; channel.metadata = { ...body, route }; this.emit(channel); } return this.snapshot(channel); } throw new Error("Broadcast sequence remained stale after three attempts."); } async stop(identity) { const channel = await this.channel(identity); channel.authorized = false; channel.active = false; channel.epoch++; channel.pending = null; channel.failed = null; this.queue.delete(channel.key); channel.controller?.abort(new Error("Broadcast stopped.")); for (const waiter of channel.waiters.splice(0)) waiter.reject(new Error("Broadcast stopped.")); this.emit(channel); if (!channel.record) { this.emit(channel); return this.snapshot(channel); } await this.mutate(channel, (r) => { r.enabled = false; r.paused = true; }); return this.serialized(async () => { for (let attempt = 0; attempt < 3; attempt++) { const record = await this.mutate(channel, (r) => { r.enabled = false; r.sequence = Math.max(r.sequence, channel.serverSequence || 0) + 1; }); const { response, body } = await this.request(channel, "DELETE", { id: record.id, sequence: record.sequence, }); if (response.status === 409) { const sequence = body.sequence ?? body.currentSequence; if (!Number.isSafeInteger(sequence)) throw new Error( "Cannot revoke stale broadcast without server sequence.", ); channel.serverSequence = sequence; continue; } if (!response.ok) throw new Error( `Broadcast stop failed (HTTP ${response.status}); retry /live off. Saved consent is off.`, ); if ( body.id !== record.id || body.sequence !== record.sequence || body.status !== "stopped" ) throw new Error("Broadcast stop returned mismatched metadata."); channel.error = null; channel.metadata = null; this.emit(channel); return this.snapshot(channel); } throw new Error("Broadcast stop sequence remained stale."); }).catch(error => { channel.error = error.message; this.emit(channel); throw error; }); } suspend() { for (const channel of this.channels.values()) { channel.epoch++; channel.authorized = false; channel.active = false; channel.pending = null; channel.controller?.abort(new Error("Broadcast account suspended.")); for (const waiter of channel.waiters.splice(0)) waiter.reject(new Error("Broadcast account suspended.")); this.queue.delete(channel.key); this.emit(channel); } } close() { this.closed = true; for (const item of this.timers) { clearTimeout(item.timer); item.resolve(); } this.timers.clear(); this.queue.clear(); for (const channel of this.channels.values()) { channel.authorized = false; channel.active = false; channel.controller?.abort(new Error("Broadcaster closed.")); for (const waiter of channel.waiters.splice(0)) waiter.reject(new Error("Broadcaster closed.")); channel.pending = null; this.emit(channel); } }}