From 7f3a70c396b498a8b10553d11cf78c3ea9a872b1 Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jan.tuomi@valuemotive.com>
Date: Mon, 19 Apr 2021 14:51:34 +0300
Subject: Should be ready now

---
 src/middleware.ts | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

(limited to 'src/middleware.ts')

diff --git a/src/middleware.ts b/src/middleware.ts
index 9aa0775..8239121 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -1,7 +1,11 @@
+import { Request, Response } from "@tinyhttp/app";
 import { Context } from "telegraf";
+import got from "got";
+import jwt from "jsonwebtoken";
+
 import { getPermittedUsers } from "./db";
 
-const auth = async (ctx: Context, next: () => Promise<void>): Promise<void> => {
+const tgAuth = async (ctx: Context, next: () => Promise<void>): Promise<void> => {
   const userId = ctx.message?.from.id;
 
   const tgUsers = await getPermittedUsers();
@@ -14,8 +18,51 @@ const auth = async (ctx: Context, next: () => Promise<void>): Promise<void> => {
   }
 };
 
+const verifyGoogleJWT = async (req: Request, res: Response, next: () => void): Promise<void> => {
+  const authHeader = req.headers.authorization || null;
+  if (!authHeader) {
+    res.sendStatus(401);
+    return;
+  }
+
+  const token = authHeader.split(" ")[1];
+  if (!token) {
+    res.sendStatus(401);
+    return;
+  }
+
+  const decoded = jwt.decode(token, { complete: true });
+  if (!decoded) {
+    res.sendStatus(401);
+    return;
+  }
+
+  const kid: string = decoded.header.kid;
+
+  const response = await got("https://www.googleapis.com/oauth2/v1/certs", { json: true });
+  const googleCerts: Record<string, string> = response.body;
+
+  const cert = googleCerts[kid];
+  if (!cert) {
+    console.error("KID not found in google certificates");
+    res.sendStatus(500);
+    return;
+  }
+
+  try {
+    jwt.verify(token, cert);
+  } catch (err) {
+    res.sendStatus(403);
+    return;
+  }
+
+  next();
+};
+
 export const tgMiddleware = {
-  auth,
+  tgAuth,
 };
 
-export const httpMiddleware = {};
+export const httpMiddleware = {
+  verifyGoogleJWT,
+};
-- 
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