import { randomBytes } from "node:crypto"; import { createServer, type ServerResponse } from "node:http"; import type { ActiveBrowserSession, StreamController } from "./types.ts"; export async function startStream( session: ActiveBrowserSession, options: { intervalMs: number }, ): Promise { if (session.stream) return session.stream; const token = randomBytes(18).toString("base64url"); const clients = new Set(); let latestImage: Buffer | null = null; let capturing = false; const server = createServer(async (request, response) => { const url = new URL(request.url ?? "/", "http://127.0.0.1"); const prefix = `/${token}`; if (!url.pathname.startsWith(prefix)) { response.writeHead(404).end("Not found"); return; } if (url.pathname === `${prefix}/events`) { response.writeHead(200, { "cache-control": "no-cache, no-transform", connection: "keep-alive", "content-type": "text/event-stream", "x-content-type-options": "nosniff", }); clients.add(response); request.on("close", () => clients.delete(response)); return; } if (url.pathname === `${prefix}/screenshot`) { if (!latestImage) { response.writeHead(503).end("Screenshot is not ready"); return; } response.writeHead(200, { "cache-control": "no-store", "content-type": "image/png", "content-length": latestImage.byteLength, "x-content-type-options": "nosniff", }); response.end(latestImage); return; } if (url.pathname === `${prefix}/logs`) { response.writeHead(200, { "cache-control": "no-store", "content-type": "application/json; charset=utf-8", "x-content-type-options": "nosniff", }); response.end(JSON.stringify({ logs: session.logs.slice(-500) })); return; } if (url.pathname === prefix || url.pathname === `${prefix}/`) { response.writeHead(200, { "cache-control": "no-store", "content-security-policy": "default-src 'none'; img-src 'self'; script-src 'unsafe-inline'; style-src 'unsafe-inline'; connect-src 'self'", "content-type": "text/html; charset=utf-8", "x-content-type-options": "nosniff", }); response.end(viewerHtml(token)); return; } response.writeHead(404).end("Not found"); }); await new Promise((resolve, reject) => { server.once("error", reject); server.listen(0, "127.0.0.1", () => { server.off("error", reject); resolve(); }); }); const address = server.address(); if (!address || typeof address === "string") throw new Error("Unable to bind stream server."); const url = `http://127.0.0.1:${address.port}/${token}/`; const capture = async () => { if (capturing || session.page.isClosed()) return; capturing = true; try { latestImage = await session.page.screenshot({ type: "png" }); const payload = JSON.stringify({ timestamp: new Date().toISOString(), url: session.page.url(), logs: session.logs.slice(-20), }); for (const client of clients) client.write(`data: ${payload}\n\n`); } catch { // A close may race the periodic capture. } finally { capturing = false; } }; await capture(); const timer = setInterval(() => void capture(), options.intervalMs); const controller: StreamController = { url, async stop() { clearInterval(timer); for (const client of clients) client.end(); clients.clear(); await new Promise((resolve) => server.close(() => resolve())); }, }; session.stream = controller; return controller; } function viewerHtml(token: string) { return ` Pi Jev Browser
Live pi browser
Live browser screenshot
`;
}