/**
* MCP server implementation with stdio and http transport support
*/
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import express from "express";
import type { ServerConfig, TransportConfig } from "../types/index.js";
import { N8nApiClientImpl } from "../clients/n8n-api-client.js";
import { ToolResponseBuilder } from "../formatters/tool-response-builder.js";
import { ToolRegistry } from "./tool-registry.js";
/**
* MCP server implementation
*/
export class MCPServerImpl {
private server: McpServer;
private n8nClient: N8nApiClientImpl;
private responseBuilder: ToolResponseBuilder;
private config: ServerConfig | null = null;
private toolRegistry: ToolRegistry | null = null;
constructor() {
this.server = new McpServer({
name: "n8n-mcp-server",
version: "1.0.0",
});
this.n8nClient = new N8nApiClientImpl("", 30000, 3);
this.responseBuilder = new ToolResponseBuilder();
}
/**
* Initialize the MCP server with configuration
*/
async initialize(config: ServerConfig): Promise<void> {
this.config = config;
// Initialize n8n client
this.n8nClient = new N8nApiClientImpl(
config.n8n.baseUrl,
config.n8n.timeout,
config.n8n.retryAttempts,
);
// Authenticate with n8n
try {
const authSuccess = await this.n8nClient.authenticate(
config.n8n.credentials,
);
if (!authSuccess) {
throw new Error("Failed to authenticate with n8n API");
}
} catch (error) {
throw new Error(`n8n API authentication failed: ${String(error)}`);
}
// Response builder is already initialized in constructor
// No need to reinitialize here
// Setup tool registry and handlers
this.toolRegistry = new ToolRegistry(
this.server,
this.n8nClient,
this.responseBuilder,
);
// Initialize tool registry (loads tools automatically)
this.toolRegistry.initialize();
this.toolRegistry.setupToolHandlers();
}
/**
* Start the server with specified transport
*/
async start(transport: TransportConfig): Promise<void> {
if (!this.config) {
throw new Error("Server not initialized. Call initialize() first.");
}
if (transport.type === "stdio") {
const stdioTransport = new StdioServerTransport();
await this.server.connect(stdioTransport);
// Don't log to stdout for stdio transport as it interferes with MCP protocol
} else {
const port = transport.port ?? 3000;
const app = express();
app.use(express.json());
console.log("🌐 Setting up HTTP transport...");
console.log(`📍 n8n URL: ${this.config.n8n.baseUrl}`);
console.log(
`🔑 API Key: ${
this.config.n8n.credentials.apiKey
? "***" + this.config.n8n.credentials.apiKey.slice(-4)
: "NOT SET"
}`,
);
// Health check endpoint
app.get("/health", (_req, res) => {
console.log("📊 Health check requested");
res.json({ status: "ok", timestamp: new Date().toISOString() });
});
// MCP Streamable HTTP endpoint
app.post("/mcp", async (req, res) => {
const transport = new StreamableHTTPServerTransport({
sessionIdGenerator: undefined,
enableJsonResponse: true,
});
res.on("close", () => {
void transport.close();
});
await this.server.connect(transport);
await transport.handleRequest(req, res, req.body);
});
app.listen(port, () => {
console.log("🚀 HTTP MCP Server started successfully!");
console.log(`🌐 Server listening on port ${String(port)}`);
console.log(`📋 Available endpoints:`);
console.log(` - GET /health - Health check endpoint`);
console.log(` - POST /mcp - MCP Streamable HTTP endpoint`);
if (this.toolRegistry) {
console.log(`🔧 MCP Tools available: ${this.toolRegistry.getRegisteredTools().join(", ")}`);
}
});
// Keep the process alive
await new Promise<void>(() => {
// Process will be kept alive by HTTP server
});
}
}
/**
* Stop the server gracefully
*/
async stop(): Promise<void> {
// Server cleanup if needed
}
/**
* Get server instance
*/
getServer(): McpServer {
return this.server;
}
}
