MCP node RAG , Rust process start

index.ts

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";
import RpcClient from "./RpcClient.js";

const server = new McpServer({
  name: "mcp-example",
  version: "1.0.0",
});

server.tool(
  "rag_search",
  "検索文字から、RAG検索 結果を返す。",
  {query: z.string().min(1, { message: '検索文字は必須です' })},
  async({query}) =>  {
    const client = new RpcClient("/work/rust/extra/qdrant_3/target/debug/rust_qdrant_3.exe");
    const resp = await client.call(
      "tools/call", 
      { 
        name: "rag_search", 
        arguments:{
          query: query
        }    
      },
    );
    client.close();    
    console.log("add結果=", resp);
    let out = "";
    // @ts-ignore
    if(resp.content[0].text){      
      // @ts-ignore
      console.log("text:"+ resp.content[0].text);      
      // @ts-ignore
      out = resp.content[0].text;
    }    
    return {content: [{type: "text", text: out }]}
  },
);

async function main() {
  const transport = new StdioServerTransport();
  await server.connect(transport);
  console.error("Example MCP Server running on stdio");
}

main().catch((error) => {
  console.error("Fatal error in main():", error);
  process.exit(1);
});

package.json

{
  "name": "mcp-example",
  "version": "1.0.0",
  "main": "index.js",
  "type": "module",
  "bin": {
    "mcp-example": "./build/index.js"
  },
  "scripts": {
    "build": "tsc",
    "build:test": "tsc && chmod 755 build/index.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "description": "",
  "files": [
    "build"
  ], 
  "dependencies": {
    "@modelcontextprotocol/sdk": "^1.9.0",
    "zod": "^3.24.2"
  },
  "devDependencies": {
    "@types/node": "^22.14.0",
    "typescript": "^5.8.3"
  }
}

RpcClient.ts

import { spawn } from "child_process";

class RpcClient {
  constructor(command) {
    // @ts-ignore
    this.proc = spawn(command);
    // @ts-ignore
    this.idCounter = 1;
    // @ts-ignore
    this.pending = new Map();

    // @ts-ignore
    this.proc.stdout.setEncoding("utf8");
    // @ts-ignore
    this.proc.stdout.on("data", (data) => this._handleData(data));
    // @ts-ignore
    this.proc.stderr.on("data", (err) => console.error("Rust stderr:", err.toString()));
    // @ts-ignore
    this.proc.on("exit", (code) => console.log(`Rust server exited (${code})`));
  }

  _handleData(data) {
    // 複数行対応
    data.split("\n").forEach((line) => {
      if (!line.trim()) return;
      try {
        const msg = JSON.parse(line);
        // @ts-ignore
        if (msg.id && this.pending.has(msg.id)) {
          // @ts-ignore
          const { resolve } = this.pending.get(msg.id);
          // @ts-ignore
          this.pending.delete(msg.id);
          resolve(msg.result);
        }
      } catch (e) {
        //console.error("JSON parse error:", e, line);
      }
    });
  }

  call(method, params = {}) {
    // @ts-ignore
    const id = this.idCounter++;
    const payload = {
      jsonrpc: "2.0",
      id,
      method,
      params,
    };

    return new Promise((resolve, reject) => {
      // @ts-ignore
      this.pending.set(id, { resolve, reject });
      // @ts-ignore
      this.proc.stdin.write(JSON.stringify(payload) + "\n");
    });
  }

  close() {
    // @ts-ignore
    this.proc.kill();
  }
}
export default RpcClient;

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "Node16",
    "moduleResolution": "Node16",
    "outDir": "./build",
    "rootDir": "./src",
    "strict": false,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}