Question

我一直在努力从Redux中的heroku应用程序获取数据，并且遇到了一些CORS错误：

 Failed to load https://app-name.herokuapp.com/users: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

第二个错误

 localhost/:1 Uncaught (in promise) TypeError: Failed to fetch

我从Express创建了Heroku应用，在响应代码中，我有

  res.setHeader('Access-Control-Allow-Origin', 'http://localhost:3000');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
  res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
  res.setHeader('Access-Control-Allow-Credentials', true);

我在Redux中的抓取功能看起来像

  const url = "https://app-name.herokuapp.com/users";
   return fetch(url, {
     method: 'GET',
     mode: 'cors',
     headers: { 'Content-Type': 'text' }
   })

在Heroku中构建Express App之前，代理已设置为“ http://localhost:3001/”，但是在Heroku中构建后，我在package.json中将其设置为“ https://app-name.herokuapp.com/users”。我不确定是否应该保持原样。

从Heroku应用程序获取时发生CORS错误

0 个答案: