/**
* Fetch API utilities for MCP WordPress Remote
*
* Provides fetch polyfill setup for Node.js environments that don't have native fetch
* and proxy-aware fetch for routing through system proxies (PAC files, env-based SOCKS/HTTP proxies)
*/
import type { RequestInit as NodeFetchRequestInit } from 'node-fetch';
import type { Agent } from 'http';
import { logger } from './utils.js';
import { getConfig } from './config.js';
import { initializeProxy, getAgentForUrl, isProxyConfigured, getProxyType } from './proxy-utils.js';
/**
* Extended RequestInit that includes the agent property for proxy support
*/
interface ProxyRequestInit extends NodeFetchRequestInit {
agent?: Agent;
}
/**
* Setup fetch polyfill for Node.js 18+ compatibility
*
* Checks if native fetch is available and loads node-fetch polyfill if needed.
* This ensures compatibility across different Node.js versions.
* Also initializes proxy support for system proxies (PAC files, env vars).
*/
export async function setupFetchPolyfill(): Promise<void> {
if (typeof globalThis.fetch !== 'function') {
logger.info('Native fetch not available, loading node-fetch polyfill...', 'SYSTEM');
try {
const { default: nodeFetch } = await import('node-fetch');
(globalThis as any).fetch = nodeFetch;
logger.info('Successfully loaded node-fetch polyfill', 'SYSTEM');
} catch (error) {
logger.error(
'Failed to load node-fetch polyfill. Please install node-fetch: npm install node-fetch',
'SYSTEM'
);
logger.error(`Error: ${error instanceof Error ? error.message : String(error)}`, 'SYSTEM');
process.exit(1);
}
} else {
logger.info('Using native fetch API', 'SYSTEM');
}
// Initialize proxy support if enabled (PAC file on macOS, env vars on all platforms)
if (getConfig().useSystemProxy) {
await initializeProxy();
} else {
logger.debug('System proxy support disabled (USE_SYSTEM_PROXY=false)', 'PROXY');
}
}
/**
* Proxy-aware fetch that routes requests through system proxies when configured
*
* On macOS: Evaluates PAC file from system proxy settings to determine proxy per-URL
* On Linux/other: Uses SOCKS_PROXY, HTTPS_PROXY, etc. environment variables
* Falls back to direct connection if no proxy is configured or USE_SYSTEM_PROXY=false
*
* @param url - The URL to fetch
* @param init - Optional fetch init options
* @returns Promise resolving to the Response
*/
export async function proxyFetch(url: string, init?: RequestInit): Promise<Response> {
// Skip proxy lookup if system proxy is disabled
if (!getConfig().useSystemProxy) {
return fetch(url, init);
}
const agent = await getAgentForUrl(url);
if (agent) {
// Use node-fetch with agent for SOCKS/HTTP proxy support
const nodeFetch = (await import('node-fetch')).default;
return nodeFetch(url, { ...init, agent } as ProxyRequestInit) as unknown as Response;
}
// Direct connection (no proxy configured or PAC returned DIRECT)
return fetch(url, init);
}
/**
* Get proxy status information for logging/debugging
*/
export function getProxyInfo() {
return {
configured: isProxyConfigured(),
type: getProxyType(),
};
}
/**
* Check if fetch is available (either native or polyfilled)
*
* @returns true if fetch is available, false otherwise
*/
export function isFetchAvailable(): boolean {
return typeof globalThis.fetch === 'function';
}
/**
* Get information about the current fetch implementation
*
* @returns Object with details about fetch availability and type
*/
export function getFetchInfo() {
const isAvailable = isFetchAvailable();
const isNative = isAvailable && globalThis.fetch.toString().includes('[native code]');
return {
available: isAvailable,
native: isNative,
polyfilled: isAvailable && !isNative,
};
}
