Powertools MCP Search Server

import { type ChildProcessWithoutNullStreams, spawn } from 'node:child_process'; import readline from 'node:readline'; /** * StdioServer is a class that manages a child process running the MCP server. * * It provides methods to start the server, stop it, and send requests to it via `stdio`. */ class StdioServer { readonly #process: ChildProcessWithoutNullStreams; readonly #inputReader: readline.Interface; readonly #requestTimeout: number; public constructor(options?: { cmd?: string; args?: string[]; }) { const cmd = options?.cmd ?? 'node'; const args = options?.args ?? ['dist/index.js']; this.#requestTimeout = process.env.CI ? 5000 : 1_000_000; // 1000 seconds in non-CI environments this.#process = spawn(cmd, args, { stdio: ['pipe', 'pipe', 'pipe'], }) as ChildProcessWithoutNullStreams; this.#inputReader = readline.createInterface({ input: this.#process.stdout, }); } /** * Start the MCP server. * * This method waits for the MCP server to start and be ready to accept requests. * It resolves when the server is listening on `stdio`. */ public async start() { await Promise.race([ (async () => { for await (const line of this.#inputReader) { if (line.includes('Powertools MCP Server running on stdio')) { return; } if (line.includes('Powertools MCP Fatal Error')) { throw new Error(`MCP Server error: ${line}`); } } })(), new Promise<void>((_, reject) => { setTimeout(() => { reject(new Error('MCP Server start timeout')); }, this.#requestTimeout); }), ]); } /** * Stop the MCP server. * * This method closes the input reader and kills the child process running the MCP server. */ public stop() { this.#inputReader.close(); this.#process.kill(); } /** * Send a request to the MCP server via `stdio`. * * This method sends a JSON-RPC request to the MCP server and waits for the response. * * @example * ```ts * const server = new Stdio(); * await server.start(); * * const response = await server.sendRequest({ * id: 1, * method: 'tools/list', * params: {} * }); * // Request: {"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}} * // Response: {"jsonrpc":"2.0","id":1,"result":{"tools":[...]} } *``` * * @param props - The request properties * @param props.id - The request ID * @param props.method - The method to call * @param props.params - The parameters for the method */ public async sendRequest<T = unknown>(props: { id: number; method: string; params?: Record<string, unknown>; }): Promise<T> { const { id, method, params = {} } = props; const req = { jsonrpc: '2.0', id, method, params }; this.#process.stdin.write(`${JSON.stringify(req)}\n`); return await Promise.race([ new Promise<T>((resolve) => { const onLine = (line: string) => { let obj: unknown; try { obj = JSON.parse(line); } catch { return; } if ((obj as { id: number }).id === id) { this.#inputReader.off('line', onLine); resolve((obj as { result: T }).result); } }; this.#inputReader.on('line', onLine); }), new Promise<T>((_, reject) => { setTimeout(() => { reject(new Error(`request ${id} timeout`)); }, this.#requestTimeout); }), ]); } } export { StdioServer };