startSSEServer.test.ts•2.39 kB
import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { it, expect, vi } from "vitest";
import { startSSEServer } from "./startSSEServer.js";
import { getRandomPort } from "get-port-please";
import { SSEClientTransport } from "@modelcontextprotocol/sdk/client/sse.js";
import { EventSource } from "eventsource";
import { setTimeout as delay } from "node:timers/promises";
import { proxyServer } from "./proxyServer.js";
if (!("EventSource" in global)) {
// @ts-expect-error - figure out how to use --experimental-eventsource with vitest
global.EventSource = EventSource;
}
it("proxies messages between SSE and stdio servers", async () => {
const stdioTransport = new StdioClientTransport({
command: "tsx",
args: ["src/simple-stdio-server.ts"],
});
const stdioClient = new Client(
{
name: "mcp-proxy",
version: "1.0.0",
},
{
capabilities: {},
},
);
await stdioClient.connect(stdioTransport);
const serverVersion = stdioClient.getServerVersion() as {
name: string;
version: string;
};
const serverCapabilities = stdioClient.getServerCapabilities() as {};
const port = await getRandomPort();
const onConnect = vi.fn();
const onClose = vi.fn();
await startSSEServer({
createServer: async () => {
const mcpServer = new Server(serverVersion, {
capabilities: serverCapabilities,
});
proxyServer({
server: mcpServer,
client: stdioClient,
serverCapabilities,
});
return mcpServer;
},
port,
endpoint: "/sse",
onConnect,
onClose,
});
const sseClient = new Client(
{
name: "sse-client",
version: "1.0.0",
},
{
capabilities: {},
},
);
const transport = new SSEClientTransport(
new URL(`http://localhost:${port}/sse`),
);
await sseClient.connect(transport);
expect(await sseClient.listResources()).toEqual({
resources: [
{
uri: "file:///example.txt",
name: "Example Resource",
},
],
});
expect(onConnect).toHaveBeenCalled();
expect(onClose).not.toHaveBeenCalled();
await sseClient.close();
await delay(100);
expect(onClose).toHaveBeenCalled();
});