YouTube Transcript DL MCP Server

import express, { Request, Response } from 'express'; import cors from 'cors'; import { BaseTransport } from './base-transport.js'; import http from 'http'; interface SSEClient { id: string; response: Response; lastSeen: number; } export class SimpleSSETransport extends BaseTransport { private app?: express.Application; private httpServer?: http.Server; private clients: Map<string, SSEClient> = new Map(); async start(): Promise<void> { if (!this.options.enabled) { this.logger.info('SSE transport is disabled'); return; } try { this.app = express(); // Enable CORS this.app.use(cors({ origin: true, credentials: true })); this.app.use(express.json({ limit: '10mb' })); // SSE endpoint for establishing connection this.app.get('/sse', (req: Request, res: Response) => { const clientId = `client_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`; // Set SSE headers res.writeHead(200, { 'Content-Type': 'text/event-stream', 'Cache-Control': 'no-cache', 'Connection': 'keep-alive', 'Access-Control-Allow-Origin': '*', 'Access-Control-Allow-Credentials': 'true' }); // Store client this.clients.set(clientId, { id: clientId, response: res, lastSeen: Date.now() }); // Send initial connection message this.sendSSEMessage(res, 'connected', { clientId, message: 'Connected to YouTube Transcript MCP Server', timestamp: new Date().toISOString() }); // Handle client disconnect req.on('close', () => { this.clients.delete(clientId); this.logger.debug(`SSE client disconnected: ${clientId}`); }); req.on('error', (err) => { this.logger.error(`SSE client error: ${clientId}`, err); this.clients.delete(clientId); }); this.logger.debug(`SSE client connected: ${clientId}`); }); // Message endpoint for receiving JSON-RPC messages this.app.post('/sse/message/:clientId', async (req: Request, res: Response) => { const { clientId } = req.params; const client = this.clients.get(clientId); if (!client) { return res.status(404).json({ error: 'Client not found' }); } try { const { jsonrpc, id, method, params } = req.body; if (jsonrpc !== '2.0') { return res.status(400).json({ error: 'Invalid JSON-RPC request' }); } // Handle MCP methods let result; switch (method) { case 'tools/list': result = await this.handleToolsList(); break; case 'tools/call': result = await this.handleToolCall(params); break; default: return res.status(400).json({ error: `Method not found: ${method}` }); } // Send response via SSE this.sendSSEMessage(client.response, 'response', { jsonrpc: '2.0', id, result }); // Acknowledge message receipt return res.json({ status: 'sent' }); } catch (error) { this.logger.error('SSE message error:', error); // Send error via SSE this.sendSSEMessage(client.response, 'error', { jsonrpc: '2.0', id: req.body.id, error: { code: -32603, message: 'Internal error', data: error instanceof Error ? error.message : 'Unknown error' } }); return res.status(500).json({ error: 'Internal server error' }); } }); // Health check endpoint this.app.get('/health', (req: Request, res: Response) => { res.json({ status: 'healthy', transport: 'sse', clients: this.clients.size, timestamp: new Date().toISOString() }); }); // Root endpoint this.app.get('/', (req: Request, res: Response) => { res.json({ name: 'YouTube Transcript MCP Server (SSE)', version: '1.0.0', transport: 'sse', endpoint: '/sse', messageEndpoint: '/sse/message/:clientId', health: '/health', clients: this.clients.size }); }); // Start HTTP server const port = this.options.port || 3001; const host = this.options.host || '0.0.0.0'; this.httpServer = this.app.listen(port, host, () => { this.logger.info(`SSE transport listening on ${host}:${port}`); }); this.isRunning = true; this.logger.info(`SSE transport started successfully on port ${port}`); // Cleanup disconnected clients periodically this.startClientCleanup(); } catch (error) { this.logger.error('Failed to start SSE transport:', error); throw error; } } private sendSSEMessage(res: Response, event: string, data: any): void { res.write(`event: ${event}\n`); res.write(`data: ${JSON.stringify(data)}\n\n`); } private async handleToolsList() { return { tools: [ { name: 'get_transcript', description: 'Extract transcript from a single YouTube video', inputSchema: { type: 'object', properties: { videoId: { type: 'string', description: 'YouTube video ID or URL' }, language: { type: 'string', description: 'Language code', default: 'en' }, format: { type: 'string', enum: ['text', 'json', 'srt'], default: 'json' } }, required: ['videoId'] } }, { name: 'get_bulk_transcripts', description: 'Extract transcripts from multiple YouTube videos', inputSchema: { type: 'object', properties: { videoIds: { type: 'array', items: { type: 'string' } }, language: { type: 'string', default: 'en' }, outputFormat: { type: 'string', enum: ['text', 'json', 'srt'], default: 'json' } }, required: ['videoIds'] } } ] }; } private async handleToolCall(params: any) { const { name, arguments: args } = params; switch (name) { case 'get_transcript': return { content: [{ type: 'text', text: JSON.stringify({ videoId: args.videoId, message: 'SSE transport is working! (Mock response)', timestamp: new Date().toISOString() }, null, 2) }] }; case 'get_bulk_transcripts': return { content: [{ type: 'text', text: JSON.stringify({ results: args.videoIds.map((id: string) => ({ videoId: id, message: 'SSE transport bulk processing! (Mock response)' })), timestamp: new Date().toISOString() }, null, 2) }] }; default: throw new Error(`Unknown tool: ${name}`); } } private startClientCleanup(): void { setInterval(() => { const now = Date.now(); const timeout = 5 * 60 * 1000; // 5 minutes for (const [clientId, client] of this.clients) { if (now - client.lastSeen > timeout) { this.logger.debug(`Cleaning up stale SSE client: ${clientId}`); this.clients.delete(clientId); } } }, 60000); // Run every minute } async stop(): Promise<void> { if (!this.isRunning) return; try { // Close all SSE connections for (const [clientId, client] of this.clients) { client.response.end(); } this.clients.clear(); if (this.httpServer) { await new Promise<void>((resolve, reject) => { this.httpServer!.close((err) => { if (err) reject(err); else resolve(); }); }); } this.isRunning = false; this.logger.info('SSE transport stopped'); } catch (error) { this.logger.error('Error stopping SSE transport:', error); throw error; } } }