Verify token before return

Summary: If the token has already expired, generate another one.

Reviewed By: aigoncharov

Differential Revision: D50410431

fbshipit-source-id: 108a3b344a1bcafd93a8d9bc94cba5c133d099d7

desktop/flipper-server-core/src/app-connectivity/certificate-exchange/certificate-utils.tsx

@@ -338,6 +338,17 @@ export const getAuthToken = async (): Promise<string> => {
   }
 
   const token = await fs.readFile(serverAuthToken);
+
+  try {
+    console.info('Verify authentication token');
+    const serverCertificate = await fs.readFile(serverCert);
+    jwt.verify(token.toString(), serverCertificate);
+    console.info('Token verification succeeded');
+  } catch (_) {
+    console.warn('Either token has expired or is invalid');
+    return generateAuthToken();
+  }
+
   return token.toString();
 };