TAK Server MCP

import { EventEmitter } from 'events'; import axios, { AxiosInstance } from 'axios'; import WebSocket from 'ws'; export interface MCPClientConfig { url: string; transport: 'http' | 'ws' | 'sse'; auth?: { type: 'bearer' | 'basic'; credentials: string; }; } export class MCPClient extends EventEmitter { private config: MCPClientConfig; private ws?: WebSocket; private axios?: AxiosInstance; private eventSource?: EventSource; private requestId = 0; private pendingRequests = new Map<number, { resolve: (value: any) => void; reject: (reason: any) => void; }>(); constructor(config: MCPClientConfig) { super(); this.config = config; if (config.transport === 'http') { this.axios = axios.create({ baseURL: config.url, headers: this.getAuthHeaders() }); } } private getAuthHeaders(): Record<string, string> { const headers: Record<string, string> = { 'Content-Type': 'application/json' }; if (this.config.auth) { if (this.config.auth.type === 'bearer') { headers['Authorization'] = `Bearer ${this.config.auth.credentials}`; } else if (this.config.auth.type === 'basic') { headers['Authorization'] = `Basic ${this.config.auth.credentials}`; } } return headers; } async connect(): Promise<void> { switch (this.config.transport) { case 'ws': return this.connectWebSocket(); case 'sse': return this.connectSSE(); case 'http': // HTTP doesn't need persistent connection return Promise.resolve(); default: throw new Error(`Unsupported transport: ${this.config.transport}`); } } private connectWebSocket(): Promise<void> { return new Promise((resolve, reject) => { this.ws = new WebSocket(this.config.url, { headers: this.getAuthHeaders() }); this.ws.on('open', () => { console.log('MCP WebSocket connected'); resolve(); }); this.ws.on('message', (data) => { try { const message = JSON.parse(data.toString()); // Handle JSON-RPC responses if (message.id && this.pendingRequests.has(message.id)) { const { resolve, reject } = this.pendingRequests.get(message.id)!; this.pendingRequests.delete(message.id); if (message.error) { reject(new Error(message.error.message)); } else { resolve(message.result); } } else if (message.method === 'notification') { // Handle server-initiated notifications this.emit('notification', message.params); } } catch (error) { console.error('Failed to parse WebSocket message:', error); } }); this.ws.on('error', (error) => { console.error('WebSocket error:', error); reject(error); }); this.ws.on('close', () => { console.log('WebSocket disconnected'); this.emit('disconnected'); }); }); } private connectSSE(): Promise<void> { // SSE implementation would go here for browser environments // For Node.js, we'd need a different approach throw new Error('SSE transport not implemented for Node.js environment'); } async listTools(): Promise<any[]> { const response = await this.callMethod('tools/list', {}); return response.tools || []; } async callTool(name: string, args: any): Promise<any> { return this.callMethod('tools/call', { name, arguments: args }); } private async callMethod(method: string, params: any): Promise<any> { const id = ++this.requestId; const request = { jsonrpc: '2.0', id, method, params }; switch (this.config.transport) { case 'http': return this.httpCall(request); case 'ws': return this.wsCall(request); default: throw new Error(`Unsupported transport: ${this.config.transport}`); } } private async httpCall(request: any): Promise<any> { if (!this.axios) { throw new Error('HTTP client not initialized'); } const response = await this.axios.post('/mcp', request); if (response.data.error) { throw new Error(response.data.error.message); } return response.data.result; } private wsCall(request: any): Promise<any> { if (!this.ws || this.ws.readyState !== WebSocket.OPEN) { throw new Error('WebSocket not connected'); } return new Promise((resolve, reject) => { this.pendingRequests.set(request.id, { resolve, reject }); this.ws!.send(JSON.stringify(request)); // Timeout after 30 seconds setTimeout(() => { if (this.pendingRequests.has(request.id)) { this.pendingRequests.delete(request.id); reject(new Error('Request timeout')); } }, 30000); }); } async disconnect(): Promise<void> { if (this.ws) { this.ws.close(); this.ws = undefined; } if (this.eventSource) { this.eventSource.close(); this.eventSource = undefined; } this.removeAllListeners(); } }