misskey/packages/backend/src/misc/fetch.ts

import * as http from 'http';
import * as https from 'https';
import CacheableLookup from 'cacheable-lookup';
import fetch from 'node-fetch';
import { HttpProxyAgent, HttpsProxyAgent } from 'hpagent';
import config from '@/config/index';
import { URL } from 'url';

export async function getJson(url: string, accept = 'application/json, */*', timeout = 10000, headers?: Record<string, string>) {
	const res = await getResponse({
		url,
		method: 'GET',
		headers: Object.assign({
			'User-Agent': config.userAgent,
			Accept: accept,
		}, headers || {}),
		timeout,
	});

	return await res.json();
}

export async function getHtml(url: string, accept = 'text/html, */*', timeout = 10000, headers?: Record<string, string>) {
	const res = await getResponse({
		url,
		method: 'GET',
		headers: Object.assign({
			'User-Agent': config.userAgent,
			Accept: accept,
		}, headers || {}),
		timeout,
	});

	return await res.text();
}

export async function getResponse(args: { url: string, method: string, body?: string, headers: Record<string, string>, timeout?: number, size?: number }) {
	const timeout = args?.timeout || 10 * 1000;

	const controller = new AbortController();
	setTimeout(() => {
		controller.abort();
	}, timeout * 6);

	const res = await fetch(args.url, {
		method: args.method,
		headers: args.headers,
		body: args.body,
		timeout,
		size: args?.size || 10 * 1024 * 1024,
		agent: getAgentByUrl,
		signal: controller.signal,
	});

	if (!res.ok) {
		throw new StatusError(`${res.status} ${res.statusText}`, res.status, res.statusText);
	}

	return res;
}

const cache = new CacheableLookup({
	maxTtl: 3600,	// 1hours
	errorTtl: 30,	// 30secs
	lookup: false,	// nativeのdns.lookupにfallbackしない
});

/**
 * Get http non-proxy agent
 */
const _http = new http.Agent({
	keepAlive: true,
	keepAliveMsecs: 30 * 1000,
	lookup: cache.lookup,
} as http.AgentOptions);

/**
 * Get https non-proxy agent
 */
const _https = new https.Agent({
	keepAlive: true,
	keepAliveMsecs: 30 * 1000,
	lookup: cache.lookup,
} as https.AgentOptions);

const maxSockets = Math.max(256, config.deliverJobConcurrency || 128);

/**
 * Get http proxy or non-proxy agent
 */
export const httpAgent = config.proxy
	? new HttpProxyAgent({
		keepAlive: true,
		keepAliveMsecs: 30 * 1000,
		maxSockets,
		maxFreeSockets: 256,
		scheduling: 'lifo',
		proxy: config.proxy,
	})
	: _http;

/**
 * Get https proxy or non-proxy agent
 */
export const httpsAgent = config.proxy
	? new HttpsProxyAgent({
		keepAlive: true,
		keepAliveMsecs: 30 * 1000,
		maxSockets,
		maxFreeSockets: 256,
		scheduling: 'lifo',
		proxy: config.proxy,
	})
	: _https;

/**
 * Get agent by URL
 * @param url URL
 * @param bypassProxy Allways bypass proxy
 */
export function getAgentByUrl(url: URL, bypassProxy = false) {
	if (bypassProxy || (config.proxyBypassHosts || []).includes(url.hostname)) {
		return url.protocol == 'http:' ? _http : _https;
	} else {
		return url.protocol == 'http:' ? httpAgent : httpsAgent;
	}
}

export class StatusError extends Error {
	public statusCode: number;
	public statusMessage?: string;
	public isClientError: boolean;

	constructor(message: string, statusCode: number, statusMessage?: string) {
		super(message);
		this.name = 'StatusError';
		this.statusCode = statusCode;
		this.statusMessage = statusMessage;
		this.isClientError = typeof this.statusCode === 'number' && this.statusCode >= 400 && this.statusCode < 500;
	}
}