CORS issue: Request header field x-msw-request-id is not allowed by Access-Control-Allow-Headers

Environment

Name	Version
msw	0.36.2
google chrome	95.0.4638.69
Ubuntu	20.0.4

Request handlers

const setup = () => {
  if (typeof window === 'undefined') {
    const { server } = require('./server');
    server.listen({ onUnhandledRequest: 'bypass' });
  } else {
    const { worker } = require('./browser');
    worker.start({ onUnhandledRequest: 'bypass' });
  }
};

export default setup;

Server setup

import { rest } from 'msw';
import { setupServer } from 'msw/node';

const server = setupServer([
rest.get('*/house/:externalId/info', (req, res, ctx) =>
    res(ctx.json(mock.house)),
  ),
  rest.get('*/house-enums', (req, res, ctx) =>
    res(ctx.json(enumMock.houseEnums)),
  ),
  rest.get('*/bff/sales-flow/:salesFlowId/ccv-card', (req, res, ctx) =>
    res(ctx.json(ccvMock.validCCVData)),
  ),
  rest.patch('*/bff/sales-flow/:salesFlowId/ccv-card', (req, res, ctx) =>
    res(ctx.status(200)),
  ),
  rest.get('*/ccv-enums', (req, res, ctx) => res(ctx.json(ccvMock.ccvEnums))),
  rest.get('*/sales-flow/:salesFlowId/diligence', (req, res, ctx) =>
    res(ctx.json(diligenceResponseMock.diligenceData)),
  ),
]);

export { server, rest };

Actual request

This request is a bypassed one made by an authentication library that we use internally. The fetch to https://sso.keycloak.com.br/auth/realms/forno/protocol/openid-connect/token passes a code received in a previous request and a redirect url and expects the authentication token as a response.

Current behavior

Receiving following error on console

Access to XMLHttpRequest at 'https://sso.keycloak.com.br/auth/realms/forno/protocol/openid-connect/token' from origin 'http://vendas.dev.quintoandar.com.br' has been blocked by CORS policy: Request header field x-msw-request-id is not allowed by Access-Control-Allow-Headers in preflight response.

Expected behavior

Request is successfully bypassed without CORS issue. Is there a way to exclude this header for bypassed requests?

[awacode21]

Figured out it was related to a misconfiguration of the whole parameters object. Related to storybook itself. So luckily it is not related to MSW itself.

[kettanaito]

I see. This doesn’t look like the error related to the x-msw-request-id issue. We’d see that header being rejected by the server. What we see in the error above is that endpoint X doesn’t allow localhost like an origin. Sorry, I don’t have enough context to suggest anything meaningful right now. I’d ask you to create a reproduction repository for this and submit a new issue.

I can only propose to double-check that MSW is enabled in Storybook (you see the console log message). Double-check with the add-on docs to be sure.