Use node-fetch instead of request (#6228)

* requestをnode-fetchになど

* format

* fix error

* t

* Fix test

src/misc/fetch.ts

@@ -0,0 +1,43 @@
+import * as http from 'http';
+import * as https from 'https';
+import * as cache from 'lookup-dns-cache';
+import fetch, { HeadersInit } from 'node-fetch';
+import { HttpProxyAgent } from 'http-proxy-agent';
+import { HttpsProxyAgent } from 'https-proxy-agent';
+import config from '../config';
+
+export async function getJson(url: string, accept = 'application/json, */*', timeout = 10000, headers?: HeadersInit) {
+	const res = await fetch(url, {
+		headers: Object.assign({
+			'User-Agent': config.userAgent,
+			Accept: accept
+		}, headers || {}),
+		timeout,
+		agent: u => u.protocol == 'http:' ? httpAgent : httpsAgent,
+	});
+
+	if (!res.ok) {
+		throw {
+			name: `StatusError`,
+			statusCode: res.status,
+			message: `${res.status} ${res.statusText}`,
+		};
+	}
+
+	return await res.json();
+}
+
+export const httpAgent = config.proxy
+	? new HttpProxyAgent(config.proxy)
+	: new http.Agent({
+		keepAlive: true,
+		keepAliveMsecs: 30 * 1000,
+	});
+
+export const httpsAgent = config.proxy
+	? new HttpsProxyAgent(config.proxy)
+	: new https.Agent({
+		keepAlive: true,
+		keepAliveMsecs: 30 * 1000,
+		lookup: cache.lookup,
+	});