Cache user info until expire

src/auth-proxy.ts

@@ -2,19 +2,30 @@ import {Request, RequestHandler} from 'express';
 import {DefaultConfig, Logger, Resolvable, UserInfo} from '.';
 import fetch from 'node-fetch';
 
+const cachedUsers: {[token: string]: UserInfo} = {};
+
 const router: RequestHandler = (req: Request, res, next) => {
 	const resolvable = new Resolvable(async () => {
 		if (!DefaultConfig.USERINFO_HEADER) {
 			return undefined;
 		}
 		const token = req.header(DefaultConfig.USERINFO_HEADER);
+		if (token && cachedUsers[token]) return cachedUsers[token];
 		const url = DefaultConfig.AUTH_PROXY_USERINFO_URL;
 		if (token === undefined || url === undefined) {
 			return undefined;
 		}
 		try {
+			const expireHeader = req.header(DefaultConfig.EXPIRE_HEADER);
+			const expireSecDate = expireHeader && parseInt(expireHeader, 10) || undefined;
+			const expiresIn = expireSecDate && expireSecDate * 1000 > Date.now() && expireSecDate * 1000 - Date.now();
 			const res = await fetch(url, {headers: [[DefaultConfig.USERINFO_HEADER, token]]});
-			return await res.json() as UserInfo;
+			const userinfo = await res.json() as UserInfo;
+			if (expiresIn) {
+				cachedUsers[token] = userinfo;
+				setTimeout(() => delete cachedUsers[token], expiresIn);
+			}
+			return userinfo;
 		} catch (e) {
 			Logger.warn(e);
 			return undefined;