3장: 전송 계층 - stdio와 Streamable HTTP

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
 
const server = new McpServer({
  name: "local-file-server",
  version: "1.0.0",
});
 
// 도구 등록
server.tool(
  "read_file",
  "파일의 내용을 읽습니다",
  { path: { type: "string", description: "파일 경로" } },
  async (params) => {
    const fs = await import("fs/promises");
    const content = await fs.readFile(params.path, "utf-8");
    return {
      content: [{ type: "text", text: content }],
    };
  }
);
 
// stdio 전송으로 서버 시작
const transport = new StdioServerTransport();
await server.connect(transport);

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
 
const transport = new StdioClientTransport({
  command: "node",
  args: ["server.js"],
});
 
const client = new Client({
  name: "my-client",
  version: "1.0.0",
});
 
await client.connect(transport);
 
// 도구 목록 조회
const tools = await client.listTools();
console.log("사용 가능한 도구:", tools);

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import express from "express";
 
const app = express();
app.use(express.json());
 
app.all("/mcp", async (req, res) => {
  const transport = new StreamableHTTPServerTransport("/mcp");
 
  const server = new McpServer({
    name: "remote-server",
    version: "1.0.0",
  });
 
  server.tool(
    "search_documents",
    "문서를 검색합니다",
    { query: { type: "string", description: "검색어" } },
    async (params) => {
      const results = await searchIndex(params.query);
      return {
        content: [{ type: "text", text: JSON.stringify(results) }],
      };
    }
  );
 
  await server.connect(transport);
  await transport.handleRequest(req, res);
});
 
app.listen(3000, () => {
  console.log("MCP 서버가 http://localhost:3000/mcp에서 실행 중입니다");
});

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
 
// 서버 로직은 전송 방식과 독립적
function createServer(): McpServer {
  const server = new McpServer({
    name: "flexible-server",
    version: "1.0.0",
  });
 
  server.tool("greet", "인사합니다", {
    name: { type: "string" },
  }, async (params) => ({
    content: [{ type: "text", text: "안녕하세요, " + params.name + "님" }],
  }));
 
  return server;
}
 
// 명령줄 인자로 전송 방식 결정
const mode = process.argv[2];
 
if (mode === "http") {
  const transport = new StreamableHTTPServerTransport("/mcp");
  const server = createServer();
  await server.connect(transport);
  // HTTP 서버 설정...
} else {
  const transport = new StdioServerTransport();
  const server = createServer();
  await server.connect(transport);
}

interface Transport {
  // 메시지를 전송합니다
  send(message: JSONRPCMessage): Promise<void>;
 
  // 수신 메시지 콜백을 설정합니다
  onMessage: (message: JSONRPCMessage) => void;
 
  // 연결 종료 콜백을 설정합니다
  onClose: () => void;
 
  // 에러 콜백을 설정합니다
  onError: (error: Error) => void;
 
  // 연결을 시작합니다
  start(): Promise<void>;
 
  // 연결을 종료합니다
  close(): Promise<void>;
}