Email MCP Server

import { Transport } from '@modelcontextprotocol/sdk/shared/transport.js' import { JSONRPCMessage } from '@modelcontextprotocol/sdk/types.js' import { v4 as uuidv4 } from 'uuid' import { WebSocket, WebSocketServer } from 'ws' import { Server } from 'http' export class WebSocketServerTransport implements Transport { private wss!: WebSocketServer private clients: Map<string, WebSocket> = new Map() onclose?: () => void onerror?: (err: Error) => void private messageHandler?: (msg: JSONRPCMessage, clientId: string) => void onconnection?: (clientId: string) => void ondisconnection?: (clientId: string) => void set onmessage(handler: ((message: JSONRPCMessage) => void) | undefined) { this.messageHandler = handler ? (msg, clientId) => { // @ts-ignore if (msg.id === undefined) { console.log('Broadcast message:', msg) return handler(msg) } // @ts-ignore return handler({ ...msg, // @ts-ignore id: clientId + ':' + msg.id, }) } : undefined } constructor({ path, server }: { path: string; server: Server }) { this.wss = new WebSocketServer({ path, server, }) } async start(): Promise<void> { this.wss.on('connection', (ws: WebSocket) => { const clientId = uuidv4() this.clients.set(clientId, ws) this.onconnection?.(clientId) ws.on('message', (data: Buffer) => { try { const msg = JSON.parse(data.toString()) this.messageHandler?.(msg, clientId) } catch (err) { this.onerror?.(new Error(`Failed to parse message: ${err}`)) } }) ws.on('close', () => { this.clients.delete(clientId) this.ondisconnection?.(clientId) }) ws.on('error', (err: Error) => { this.onerror?.(err) }) }) } async send(msg: JSONRPCMessage, clientId?: string): Promise<void> { const [cId, msgId] = clientId?.split(':') ?? [] // @ts-ignore msg.id = parseInt(msgId) const data = JSON.stringify(msg) const deadClients: string[] = [] if (cId) { // Send to specific client const client = this.clients.get(cId) if (client?.readyState === WebSocket.OPEN) { client.send(data) } else { this.clients.delete(cId) this.ondisconnection?.(cId) } } for (const [id, client] of this.clients.entries()) { if (client.readyState !== WebSocket.OPEN) { deadClients.push(id) } } // Cleanup dead clients deadClients.forEach((id) => { this.clients.delete(id) this.ondisconnection?.(id) }) } async broadcast(msg: JSONRPCMessage): Promise<void> { return this.send(msg) } async close(): Promise<void> { return new Promise((resolve) => { this.wss.close(() => { this.clients.clear() resolve() }) }) } }