server.js 9.0 KB

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  1. const crypto = require('crypto');
  2. const http = require('http');
  3. const fs = require('fs');
  4. const path = require('path');
  5. // ========== WebSocket Protocol (RFC 6455) ==========
  6. const OPCODES = { TEXT: 0x01, CLOSE: 0x08, PING: 0x09, PONG: 0x0A };
  7. const WS_MAGIC = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';
  8. function computeAcceptKey(clientKey) {
  9. return crypto.createHash('sha1').update(clientKey + WS_MAGIC).digest('base64');
  10. }
  11. function encodeFrame(opcode, payload) {
  12. const fin = 0x80;
  13. const len = payload.length;
  14. let header;
  15. if (len < 126) {
  16. header = Buffer.alloc(2);
  17. header[0] = fin | opcode;
  18. header[1] = len;
  19. } else if (len < 65536) {
  20. header = Buffer.alloc(4);
  21. header[0] = fin | opcode;
  22. header[1] = 126;
  23. header.writeUInt16BE(len, 2);
  24. } else {
  25. header = Buffer.alloc(10);
  26. header[0] = fin | opcode;
  27. header[1] = 127;
  28. header.writeBigUInt64BE(BigInt(len), 2);
  29. }
  30. return Buffer.concat([header, payload]);
  31. }
  32. function decodeFrame(buffer) {
  33. if (buffer.length < 2) return null;
  34. const secondByte = buffer[1];
  35. const opcode = buffer[0] & 0x0F;
  36. const masked = (secondByte & 0x80) !== 0;
  37. let payloadLen = secondByte & 0x7F;
  38. let offset = 2;
  39. if (!masked) throw new Error('Client frames must be masked');
  40. if (payloadLen === 126) {
  41. if (buffer.length < 4) return null;
  42. payloadLen = buffer.readUInt16BE(2);
  43. offset = 4;
  44. } else if (payloadLen === 127) {
  45. if (buffer.length < 10) return null;
  46. payloadLen = Number(buffer.readBigUInt64BE(2));
  47. offset = 10;
  48. }
  49. const maskOffset = offset;
  50. const dataOffset = offset + 4;
  51. const totalLen = dataOffset + payloadLen;
  52. if (buffer.length < totalLen) return null;
  53. const mask = buffer.slice(maskOffset, dataOffset);
  54. const data = Buffer.alloc(payloadLen);
  55. for (let i = 0; i < payloadLen; i++) {
  56. data[i] = buffer[dataOffset + i] ^ mask[i % 4];
  57. }
  58. return { opcode, payload: data, bytesConsumed: totalLen };
  59. }
  60. // ========== Configuration ==========
  61. const PORT = process.env.BRAINSTORM_PORT || (49152 + Math.floor(Math.random() * 16383));
  62. const HOST = process.env.BRAINSTORM_HOST || '127.0.0.1';
  63. const URL_HOST = process.env.BRAINSTORM_URL_HOST || (HOST === '127.0.0.1' ? 'localhost' : HOST);
  64. const SCREEN_DIR = process.env.BRAINSTORM_DIR || '/tmp/brainstorm';
  65. const MIME_TYPES = {
  66. '.html': 'text/html', '.css': 'text/css', '.js': 'application/javascript',
  67. '.json': 'application/json', '.png': 'image/png', '.jpg': 'image/jpeg',
  68. '.jpeg': 'image/jpeg', '.gif': 'image/gif', '.svg': 'image/svg+xml'
  69. };
  70. // ========== Templates and Constants ==========
  71. const WAITING_PAGE = `<!DOCTYPE html>
  72. <html>
  73. <head><title>Brainstorm Companion</title>
  74. <style>body { font-family: system-ui, sans-serif; padding: 2rem; max-width: 800px; margin: 0 auto; }
  75. h1 { color: #333; } p { color: #666; }</style>
  76. </head>
  77. <body><h1>Brainstorm Companion</h1>
  78. <p>Waiting for Claude to push a screen...</p></body></html>`;
  79. const frameTemplate = fs.readFileSync(path.join(__dirname, 'frame-template.html'), 'utf-8');
  80. const helperScript = fs.readFileSync(path.join(__dirname, 'helper.js'), 'utf-8');
  81. const helperInjection = '<script>\n' + helperScript + '\n</script>';
  82. // ========== Helper Functions ==========
  83. function isFullDocument(html) {
  84. const trimmed = html.trimStart().toLowerCase();
  85. return trimmed.startsWith('<!doctype') || trimmed.startsWith('<html');
  86. }
  87. function wrapInFrame(content) {
  88. return frameTemplate.replace('<!-- CONTENT -->', content);
  89. }
  90. function getNewestScreen() {
  91. const files = fs.readdirSync(SCREEN_DIR)
  92. .filter(f => f.endsWith('.html'))
  93. .map(f => {
  94. const fp = path.join(SCREEN_DIR, f);
  95. return { path: fp, mtime: fs.statSync(fp).mtime.getTime() };
  96. })
  97. .sort((a, b) => b.mtime - a.mtime);
  98. return files.length > 0 ? files[0].path : null;
  99. }
  100. // ========== HTTP Request Handler ==========
  101. function handleRequest(req, res) {
  102. if (req.method === 'GET' && req.url === '/') {
  103. const screenFile = getNewestScreen();
  104. let html = screenFile
  105. ? (raw => isFullDocument(raw) ? raw : wrapInFrame(raw))(fs.readFileSync(screenFile, 'utf-8'))
  106. : WAITING_PAGE;
  107. if (html.includes('</body>')) {
  108. html = html.replace('</body>', helperInjection + '\n</body>');
  109. } else {
  110. html += helperInjection;
  111. }
  112. res.writeHead(200, { 'Content-Type': 'text/html' });
  113. res.end(html);
  114. } else if (req.method === 'GET' && req.url.startsWith('/files/')) {
  115. const fileName = req.url.slice(7);
  116. const filePath = path.join(SCREEN_DIR, path.basename(fileName));
  117. if (!fs.existsSync(filePath)) {
  118. res.writeHead(404);
  119. res.end('Not found');
  120. return;
  121. }
  122. const ext = path.extname(filePath).toLowerCase();
  123. const contentType = MIME_TYPES[ext] || 'application/octet-stream';
  124. res.writeHead(200, { 'Content-Type': contentType });
  125. res.end(fs.readFileSync(filePath));
  126. } else {
  127. res.writeHead(404);
  128. res.end('Not found');
  129. }
  130. }
  131. // ========== WebSocket Connection Handling ==========
  132. const clients = new Set();
  133. function handleUpgrade(req, socket) {
  134. const key = req.headers['sec-websocket-key'];
  135. if (!key) { socket.destroy(); return; }
  136. const accept = computeAcceptKey(key);
  137. socket.write(
  138. 'HTTP/1.1 101 Switching Protocols\r\n' +
  139. 'Upgrade: websocket\r\n' +
  140. 'Connection: Upgrade\r\n' +
  141. 'Sec-WebSocket-Accept: ' + accept + '\r\n\r\n'
  142. );
  143. let buffer = Buffer.alloc(0);
  144. clients.add(socket);
  145. socket.on('data', (chunk) => {
  146. buffer = Buffer.concat([buffer, chunk]);
  147. while (buffer.length > 0) {
  148. let result;
  149. try {
  150. result = decodeFrame(buffer);
  151. } catch (e) {
  152. socket.end(encodeFrame(OPCODES.CLOSE, Buffer.alloc(0)));
  153. clients.delete(socket);
  154. return;
  155. }
  156. if (!result) break;
  157. buffer = buffer.slice(result.bytesConsumed);
  158. switch (result.opcode) {
  159. case OPCODES.TEXT:
  160. handleMessage(result.payload.toString());
  161. break;
  162. case OPCODES.CLOSE:
  163. socket.end(encodeFrame(OPCODES.CLOSE, Buffer.alloc(0)));
  164. clients.delete(socket);
  165. return;
  166. case OPCODES.PING:
  167. socket.write(encodeFrame(OPCODES.PONG, result.payload));
  168. break;
  169. case OPCODES.PONG:
  170. break;
  171. default: {
  172. const closeBuf = Buffer.alloc(2);
  173. closeBuf.writeUInt16BE(1003);
  174. socket.end(encodeFrame(OPCODES.CLOSE, closeBuf));
  175. clients.delete(socket);
  176. return;
  177. }
  178. }
  179. }
  180. });
  181. socket.on('close', () => clients.delete(socket));
  182. socket.on('error', () => clients.delete(socket));
  183. }
  184. function handleMessage(text) {
  185. let event;
  186. try {
  187. event = JSON.parse(text);
  188. } catch (e) {
  189. console.error('Failed to parse WebSocket message:', e.message);
  190. return;
  191. }
  192. console.log(JSON.stringify({ source: 'user-event', ...event }));
  193. if (event.choice) {
  194. const eventsFile = path.join(SCREEN_DIR, '.events');
  195. fs.appendFileSync(eventsFile, JSON.stringify(event) + '\n');
  196. }
  197. }
  198. function broadcast(msg) {
  199. const frame = encodeFrame(OPCODES.TEXT, Buffer.from(JSON.stringify(msg)));
  200. for (const socket of clients) {
  201. try { socket.write(frame); } catch (e) { clients.delete(socket); }
  202. }
  203. }
  204. // ========== File Watching ==========
  205. const debounceTimers = new Map();
  206. // ========== Server Startup ==========
  207. function startServer() {
  208. if (!fs.existsSync(SCREEN_DIR)) fs.mkdirSync(SCREEN_DIR, { recursive: true });
  209. // Track known files to distinguish new screens from updates.
  210. // macOS fs.watch reports 'rename' for both new files and overwrites,
  211. // so we can't rely on eventType alone.
  212. const knownFiles = new Set(
  213. fs.readdirSync(SCREEN_DIR).filter(f => f.endsWith('.html'))
  214. );
  215. const server = http.createServer(handleRequest);
  216. server.on('upgrade', handleUpgrade);
  217. const watcher = fs.watch(SCREEN_DIR, (eventType, filename) => {
  218. if (!filename || !filename.endsWith('.html')) return;
  219. if (debounceTimers.has(filename)) clearTimeout(debounceTimers.get(filename));
  220. debounceTimers.set(filename, setTimeout(() => {
  221. debounceTimers.delete(filename);
  222. const filePath = path.join(SCREEN_DIR, filename);
  223. if (!fs.existsSync(filePath)) return; // file was deleted
  224. if (!knownFiles.has(filename)) {
  225. knownFiles.add(filename);
  226. const eventsFile = path.join(SCREEN_DIR, '.events');
  227. if (fs.existsSync(eventsFile)) fs.unlinkSync(eventsFile);
  228. console.log(JSON.stringify({ type: 'screen-added', file: filePath }));
  229. } else {
  230. console.log(JSON.stringify({ type: 'screen-updated', file: filePath }));
  231. }
  232. broadcast({ type: 'reload' });
  233. }, 100));
  234. });
  235. watcher.on('error', (err) => console.error('fs.watch error:', err.message));
  236. server.listen(PORT, HOST, () => {
  237. const info = JSON.stringify({
  238. type: 'server-started', port: Number(PORT), host: HOST,
  239. url_host: URL_HOST, url: 'http://' + URL_HOST + ':' + PORT,
  240. screen_dir: SCREEN_DIR
  241. });
  242. console.log(info);
  243. fs.writeFileSync(path.join(SCREEN_DIR, '.server-info'), info + '\n');
  244. });
  245. }
  246. if (require.main === module) {
  247. startServer();
  248. }
  249. module.exports = { computeAcceptKey, encodeFrame, decodeFrame, OPCODES };