import type { IncomingMessage, ServerResponse } from "node:http";
import type { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
import { type RequestHandlers, createBaseHttpServer } from "../utils";
export const startSSEMcpServer = async (
server: Server,
endpoint = "/sse",
port = 1122,
): Promise<void> => {
const activeTransports: Record<string, SSEServerTransport> = {};
// Define the request handler for SSE-specific logic
const handleRequest: RequestHandlers["handleRequest"] = async (
req: IncomingMessage,
res: ServerResponse,
) => {
if (!req.url) {
res.writeHead(400).end("No URL");
return;
}
const reqUrl = new URL(req.url, "http://localhost");
// Handle GET requests to the SSE endpoint
if (req.method === "GET" && reqUrl.pathname === endpoint) {
const transport = new SSEServerTransport("/messages", res);
activeTransports[transport.sessionId] = transport;
let closed = false;
res.on("close", async () => {
closed = true;
try {
await server.close();
} catch (error) {
console.error("Error closing server:", error);
}
delete activeTransports[transport.sessionId];
});
try {
await server.connect(transport);
await transport.send({
jsonrpc: "2.0",
method: "sse/connection",
params: { message: "SSE Connection established" },
});
} catch (error) {
if (!closed) {
console.error("Error connecting to server:", error);
res.writeHead(500).end("Error connecting to server");
}
}
return;
}
// Handle POST requests to the messages endpoint
if (req.method === "POST" && req.url?.startsWith("/messages")) {
const sessionId = new URL(
req.url,
"https://example.com",
).searchParams.get("sessionId");
if (!sessionId) {
res.writeHead(400).end("No sessionId");
return;
}
const activeTransport: SSEServerTransport | undefined =
activeTransports[sessionId];
if (!activeTransport) {
res.writeHead(400).end("No active transport");
return;
}
await activeTransport.handlePostMessage(req, res);
return;
}
// If we reach here, no handler matched
res.writeHead(404).end("Not found");
};
// Custom cleanup for SSE server
const cleanup = () => {
// Close all active transports
for (const transport of Object.values(activeTransports)) {
transport.close();
}
server.close();
};
// Create the HTTP server using our factory
createBaseHttpServer(port, endpoint, {
handleRequest,
cleanup,
serverType: "SSE Server",
});
};
