IBM i MCP Server

/** * @fileoverview Provides a utility function to make fetch requests with a specified timeout. * @module src/utils/network/fetchWithTimeout */ import { logger } from "@/utils/internal/logger.js"; // Adjusted import path import type { RequestContext } from "@/utils/internal/requestContext.js"; // Adjusted import path import { McpError, JsonRpcErrorCode } from "@/types-global/errors.js"; /** * Options for the fetchWithTimeout utility. * Extends standard RequestInit but omits 'signal' as it's handled internally. */ export type FetchWithTimeoutOptions = Omit<RequestInit, "signal">; /** * Fetches a resource with a specified timeout. * * @param url - The URL to fetch. * @param timeoutMs - The timeout duration in milliseconds. * @param context - The request context for logging. * @param options - Optional fetch options (RequestInit), excluding 'signal'. * @returns A promise that resolves to the Response object. * @throws {McpError} If the request times out or another fetch-related error occurs. */ export async function fetchWithTimeout( url: string | URL, timeoutMs: number, context: RequestContext, options?: FetchWithTimeoutOptions, ): Promise<Response> { const controller = new AbortController(); const timeoutId = setTimeout(() => controller.abort(), timeoutMs); const urlString = url.toString(); const operationDescription = `fetch ${options?.method || "GET"} ${urlString}`; logger.debug( context, `Attempting ${operationDescription} with ${timeoutMs}ms timeout.`, ); try { const response = await fetch(url, { ...options, signal: controller.signal, }); clearTimeout(timeoutId); if (!response.ok) { const errorBody = await response .text() .catch(() => "Could not read response body"); logger.error( { ...context, statusCode: response.status, statusText: response.statusText, responseBody: errorBody, errorSource: "FetchHttpError", }, `Fetch failed for ${urlString} with status ${response.status}.`, ); throw new McpError( JsonRpcErrorCode.ServiceUnavailable, `Fetch failed for ${urlString}. Status: ${response.status}`, { ...context, statusCode: response.status, statusText: response.statusText, responseBody: errorBody, }, ); } logger.debug( context, `Successfully fetched ${urlString}. Status: ${response.status}`, ); return response; } catch (error) { clearTimeout(timeoutId); if (error instanceof Error && error.name === "AbortError") { logger.error( { ...context, errorSource: "FetchTimeout", }, `${operationDescription} timed out after ${timeoutMs}ms.`, ); throw new McpError( JsonRpcErrorCode.Timeout, `${operationDescription} timed out.`, { ...context, errorSource: "FetchTimeout" }, ); } // Log and re-throw other errors as McpError const errorMessage = error instanceof Error ? error.message : String(error); logger.error( { ...context, originalErrorName: error instanceof Error ? error.name : "UnknownError", errorSource: "FetchNetworkError", }, `Network error during ${operationDescription}: ${errorMessage}`, ); if (error instanceof McpError) { // If it's already an McpError, re-throw it throw error; } throw new McpError( JsonRpcErrorCode.ServiceUnavailable, // Generic error for network/service issues `Network error during ${operationDescription}: ${errorMessage}`, { ...context, originalErrorName: error instanceof Error ? error.name : "UnknownError", errorSource: "FetchNetworkErrorWrapper", }, ); } }