339 lines
10 KiB
JavaScript
339 lines
10 KiB
JavaScript
const crypto = require('crypto');
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const http = require('http');
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const fs = require('fs');
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const path = require('path');
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// ========== WebSocket Protocol (RFC 6455) ==========
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const OPCODES = { TEXT: 0x01, CLOSE: 0x08, PING: 0x09, PONG: 0x0A };
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const WS_MAGIC = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
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function computeAcceptKey(clientKey) {
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return crypto.createHash('sha1').update(clientKey + WS_MAGIC).digest('base64');
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}
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function encodeFrame(opcode, payload) {
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const fin = 0x80;
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const len = payload.length;
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let header;
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if (len < 126) {
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header = Buffer.alloc(2);
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header[0] = fin | opcode;
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header[1] = len;
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} else if (len < 65536) {
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header = Buffer.alloc(4);
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header[0] = fin | opcode;
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header[1] = 126;
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header.writeUInt16BE(len, 2);
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} else {
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header = Buffer.alloc(10);
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header[0] = fin | opcode;
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header[1] = 127;
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header.writeBigUInt64BE(BigInt(len), 2);
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}
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return Buffer.concat([header, payload]);
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}
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function decodeFrame(buffer) {
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if (buffer.length < 2) return null;
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const secondByte = buffer[1];
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const opcode = buffer[0] & 0x0F;
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const masked = (secondByte & 0x80) !== 0;
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let payloadLen = secondByte & 0x7F;
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let offset = 2;
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if (!masked) throw new Error('Client frames must be masked');
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if (payloadLen === 126) {
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if (buffer.length < 4) return null;
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payloadLen = buffer.readUInt16BE(2);
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offset = 4;
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} else if (payloadLen === 127) {
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if (buffer.length < 10) return null;
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payloadLen = Number(buffer.readBigUInt64BE(2));
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offset = 10;
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}
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const maskOffset = offset;
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const dataOffset = offset + 4;
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const totalLen = dataOffset + payloadLen;
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if (buffer.length < totalLen) return null;
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const mask = buffer.slice(maskOffset, dataOffset);
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const data = Buffer.alloc(payloadLen);
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for (let i = 0; i < payloadLen; i++) {
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data[i] = buffer[dataOffset + i] ^ mask[i % 4];
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}
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return { opcode, payload: data, bytesConsumed: totalLen };
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}
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// ========== Configuration ==========
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const PORT = process.env.BRAINSTORM_PORT || (49152 + Math.floor(Math.random() * 16383));
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const HOST = process.env.BRAINSTORM_HOST || '127.0.0.1';
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const URL_HOST = process.env.BRAINSTORM_URL_HOST || (HOST === '127.0.0.1' ? 'localhost' : HOST);
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const SCREEN_DIR = process.env.BRAINSTORM_DIR || '/tmp/brainstorm';
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const OWNER_PID = process.env.BRAINSTORM_OWNER_PID ? Number(process.env.BRAINSTORM_OWNER_PID) : null;
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const MIME_TYPES = {
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'.html': 'text/html', '.css': 'text/css', '.js': 'application/javascript',
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'.json': 'application/json', '.png': 'image/png', '.jpg': 'image/jpeg',
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'.jpeg': 'image/jpeg', '.gif': 'image/gif', '.svg': 'image/svg+xml'
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};
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// ========== Templates and Constants ==========
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const WAITING_PAGE = `<!DOCTYPE html>
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<html>
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<head><meta charset="utf-8"><title>Brainstorm Companion</title>
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<style>body { font-family: system-ui, sans-serif; padding: 2rem; max-width: 800px; margin: 0 auto; }
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h1 { color: #333; } p { color: #666; }</style>
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</head>
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<body><h1>Brainstorm Companion</h1>
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<p>Waiting for the agent to push a screen...</p></body></html>`;
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const frameTemplate = fs.readFileSync(path.join(__dirname, 'frame-template.html'), 'utf-8');
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const helperScript = fs.readFileSync(path.join(__dirname, 'helper.js'), 'utf-8');
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const helperInjection = '<script>\n' + helperScript + '\n</script>';
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// ========== Helper Functions ==========
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function isFullDocument(html) {
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const trimmed = html.trimStart().toLowerCase();
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return trimmed.startsWith('<!doctype') || trimmed.startsWith('<html');
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}
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function wrapInFrame(content) {
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return frameTemplate.replace('<!-- CONTENT -->', content);
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}
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function getNewestScreen() {
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const files = fs.readdirSync(SCREEN_DIR)
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.filter(f => f.endsWith('.html'))
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.map(f => {
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const fp = path.join(SCREEN_DIR, f);
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return { path: fp, mtime: fs.statSync(fp).mtime.getTime() };
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})
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.sort((a, b) => b.mtime - a.mtime);
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return files.length > 0 ? files[0].path : null;
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}
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// ========== HTTP Request Handler ==========
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function handleRequest(req, res) {
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touchActivity();
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if (req.method === 'GET' && req.url === '/') {
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const screenFile = getNewestScreen();
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let html = screenFile
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? (raw => isFullDocument(raw) ? raw : wrapInFrame(raw))(fs.readFileSync(screenFile, 'utf-8'))
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: WAITING_PAGE;
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if (html.includes('</body>')) {
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html = html.replace('</body>', helperInjection + '\n</body>');
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} else {
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html += helperInjection;
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}
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res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });
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res.end(html);
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} else if (req.method === 'GET' && req.url.startsWith('/files/')) {
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const fileName = req.url.slice(7);
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const filePath = path.join(SCREEN_DIR, path.basename(fileName));
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if (!fs.existsSync(filePath)) {
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res.writeHead(404);
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res.end('Not found');
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return;
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}
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const ext = path.extname(filePath).toLowerCase();
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const contentType = MIME_TYPES[ext] || 'application/octet-stream';
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res.writeHead(200, { 'Content-Type': contentType });
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res.end(fs.readFileSync(filePath));
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} else {
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res.writeHead(404);
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res.end('Not found');
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}
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}
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// ========== WebSocket Connection Handling ==========
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const clients = new Set();
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function handleUpgrade(req, socket) {
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const key = req.headers['sec-websocket-key'];
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if (!key) { socket.destroy(); return; }
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const accept = computeAcceptKey(key);
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socket.write(
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'HTTP/1.1 101 Switching Protocols\r\n' +
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'Upgrade: websocket\r\n' +
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'Connection: Upgrade\r\n' +
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'Sec-WebSocket-Accept: ' + accept + '\r\n\r\n'
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);
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let buffer = Buffer.alloc(0);
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clients.add(socket);
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socket.on('data', (chunk) => {
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buffer = Buffer.concat([buffer, chunk]);
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while (buffer.length > 0) {
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let result;
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try {
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result = decodeFrame(buffer);
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} catch (e) {
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socket.end(encodeFrame(OPCODES.CLOSE, Buffer.alloc(0)));
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clients.delete(socket);
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return;
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}
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if (!result) break;
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buffer = buffer.slice(result.bytesConsumed);
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switch (result.opcode) {
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case OPCODES.TEXT:
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handleMessage(result.payload.toString());
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break;
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case OPCODES.CLOSE:
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socket.end(encodeFrame(OPCODES.CLOSE, Buffer.alloc(0)));
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clients.delete(socket);
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return;
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case OPCODES.PING:
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socket.write(encodeFrame(OPCODES.PONG, result.payload));
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break;
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case OPCODES.PONG:
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break;
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default: {
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const closeBuf = Buffer.alloc(2);
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closeBuf.writeUInt16BE(1003);
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socket.end(encodeFrame(OPCODES.CLOSE, closeBuf));
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clients.delete(socket);
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return;
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}
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}
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}
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});
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socket.on('close', () => clients.delete(socket));
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socket.on('error', () => clients.delete(socket));
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}
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function handleMessage(text) {
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let event;
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try {
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event = JSON.parse(text);
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} catch (e) {
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console.error('Failed to parse WebSocket message:', e.message);
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return;
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}
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touchActivity();
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console.log(JSON.stringify({ source: 'user-event', ...event }));
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if (event.choice) {
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const eventsFile = path.join(SCREEN_DIR, '.events');
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fs.appendFileSync(eventsFile, JSON.stringify(event) + '\n');
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}
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}
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function broadcast(msg) {
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const frame = encodeFrame(OPCODES.TEXT, Buffer.from(JSON.stringify(msg)));
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for (const socket of clients) {
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try { socket.write(frame); } catch (e) { clients.delete(socket); }
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}
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}
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// ========== Activity Tracking ==========
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const IDLE_TIMEOUT_MS = 30 * 60 * 1000; // 30 minutes
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let lastActivity = Date.now();
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function touchActivity() {
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lastActivity = Date.now();
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}
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// ========== File Watching ==========
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const debounceTimers = new Map();
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// ========== Server Startup ==========
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function startServer() {
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if (!fs.existsSync(SCREEN_DIR)) fs.mkdirSync(SCREEN_DIR, { recursive: true });
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// Track known files to distinguish new screens from updates.
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// macOS fs.watch reports 'rename' for both new files and overwrites,
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// so we can't rely on eventType alone.
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const knownFiles = new Set(
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fs.readdirSync(SCREEN_DIR).filter(f => f.endsWith('.html'))
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);
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const server = http.createServer(handleRequest);
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server.on('upgrade', handleUpgrade);
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const watcher = fs.watch(SCREEN_DIR, (eventType, filename) => {
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if (!filename || !filename.endsWith('.html')) return;
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if (debounceTimers.has(filename)) clearTimeout(debounceTimers.get(filename));
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debounceTimers.set(filename, setTimeout(() => {
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debounceTimers.delete(filename);
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const filePath = path.join(SCREEN_DIR, filename);
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if (!fs.existsSync(filePath)) return; // file was deleted
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touchActivity();
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if (!knownFiles.has(filename)) {
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knownFiles.add(filename);
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const eventsFile = path.join(SCREEN_DIR, '.events');
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if (fs.existsSync(eventsFile)) fs.unlinkSync(eventsFile);
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console.log(JSON.stringify({ type: 'screen-added', file: filePath }));
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} else {
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console.log(JSON.stringify({ type: 'screen-updated', file: filePath }));
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}
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broadcast({ type: 'reload' });
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}, 100));
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});
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watcher.on('error', (err) => console.error('fs.watch error:', err.message));
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function shutdown(reason) {
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console.log(JSON.stringify({ type: 'server-stopped', reason }));
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const infoFile = path.join(SCREEN_DIR, '.server-info');
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if (fs.existsSync(infoFile)) fs.unlinkSync(infoFile);
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fs.writeFileSync(
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path.join(SCREEN_DIR, '.server-stopped'),
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JSON.stringify({ reason, timestamp: Date.now() }) + '\n'
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);
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watcher.close();
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clearInterval(lifecycleCheck);
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server.close(() => process.exit(0));
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}
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function ownerAlive() {
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if (!OWNER_PID) return true;
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try { process.kill(OWNER_PID, 0); return true; } catch (e) { return false; }
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}
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// Check every 60s: exit if owner process died or idle for 30 minutes
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const lifecycleCheck = setInterval(() => {
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if (!ownerAlive()) shutdown('owner process exited');
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else if (Date.now() - lastActivity > IDLE_TIMEOUT_MS) shutdown('idle timeout');
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}, 60 * 1000);
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lifecycleCheck.unref();
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server.listen(PORT, HOST, () => {
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const info = JSON.stringify({
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type: 'server-started', port: Number(PORT), host: HOST,
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url_host: URL_HOST, url: 'http://' + URL_HOST + ':' + PORT,
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screen_dir: SCREEN_DIR
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});
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console.log(info);
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fs.writeFileSync(path.join(SCREEN_DIR, '.server-info'), info + '\n');
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});
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}
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if (require.main === module) {
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startServer();
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}
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module.exports = { computeAcceptKey, encodeFrame, decodeFrame, OPCODES };
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