import { WebStandardStreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/webStandardStreamableHttp.js";
import { createServer } from "./server.ts";
import { version } from "../package.json";
const sessions = new Map<string, WebStandardStreamableHTTPServerTransport>();
const PORT = Number(process.env.PORT) || 3000;
function jsonError(code: number, message: string, id: string | number | null = null): Response {
return new Response(JSON.stringify({ jsonrpc: "2.0", error: { code, message }, id }), {
status: 400,
headers: { "Content-Type": "application/json" },
});
}
export default {
port: PORT,
async fetch(req: Request): Promise<Response> {
const url = new URL(req.url);
if (url.pathname !== "/mcp") {
return new Response("Not found", { status: 404 });
}
const accept = req.headers.get("accept") ?? "";
if (!accept.includes("text/event-stream")) {
const newHeaders = new Headers(req.headers);
newHeaders.set("accept", "application/json, text/event-stream");
req = new Request(req.url, {
method: req.method,
headers: newHeaders,
body: req.body,
duplex: "half",
});
}
if (req.method === "POST") {
const sessionId = req.headers.get("mcp-session-id");
let transport: WebStandardStreamableHTTPServerTransport;
if (sessionId && sessions.has(sessionId)) {
transport = sessions.get(sessionId)!;
} else {
transport = new WebStandardStreamableHTTPServerTransport({
sessionIdGenerator: () => crypto.randomUUID(),
enableJsonResponse: true,
onsessioninitialized: (id) => {
sessions.set(id, transport);
},
});
transport.onclose = () => {
if (transport.sessionId) {
sessions.delete(transport.sessionId);
}
};
const server = createServer();
await server.connect(transport);
}
return transport.handleRequest(req);
}
if (req.method === "DELETE") {
const sessionId = req.headers.get("mcp-session-id");
if (!sessionId || !sessions.has(sessionId)) {
return jsonError(-32000, "Invalid session");
}
const transport = sessions.get(sessionId)!;
await transport.close();
sessions.delete(sessionId);
return new Response(null, { status: 204 });
}
return new Response("Method not allowed", { status: 405 });
},
};
console.log(`reddit-mcp v${version} running on http://localhost:${PORT}/mcp`);
