CORS发行vue/express/axios

我有一个VueJS应用程序使用ExpressJS api。试图从前端登录页表单点击快速路线，通过SendGrid发送“联系我们”电子邮件，但在heroku上的生产中出现代理错误

以下是我的组件中的方法：

 async sendContactMessage() {
      console.log('email valid? ', this.validateEmail(this.contactEmail))
      if (!this.validateEmail(this.contactEmail)) {
        this.contactNotice = "Please enter a valid email."
      }
      
      else if (this.contactMessage.length < 10) {
        this.contactNotice = " The message is too short"
      } else {
        await MailersService.sendMessage({
          email: this.contactEmail,
          message: this.contactMessage
        })
        this.showContact = false
      }
    },

在快车方面，以下是我发布的路线：

router.post('/question', async (req, res, next) => {
  console.log('in Express, sending mail from contact form. this is request: ', req)
  let newMessage = req.body
  console.log("new message object is: ", newMessage)
  const msg = {
    to: 'contact@companydomain.com',
    from: req.body.email, // Use the email address or domain you verified above
    subject: 'Message from Beta Signup Form',
    text: req.body.message
  };
  await sgMail.send(msg);

  res.json({
    success: true, message: 'ok' 
  });   // respond back to request
});

在cors的app.js中，我有：

app.use(cors());
app.use( function (req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
})

这在本地起作用，但在Heroku上，它抛出错误：

Access to XMLHttpRequest at 'https://...-api.herokuapp.com/api/contacts/question' from origin 'https://....com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

---

您是否处理

选项

呼叫？听起来好像你没有处理，这导致它从来没有真正打过电话；非挥发性物质。这就是app.use（cors（））的作用app.options（'*'，cors（））。尝试此操作时运气不佳。错误似乎表明这是需要从客户端提供的信息，对吗？您是否处理

选项

调用？听起来好像你没有处理，这导致它从来没有真正打过电话；非挥发性物质。这就是app.use（cors（））的作用app.options（'*'，cors（））。尝试此操作时运气不佳。错误似乎表明这是需要从客户端提供的东西，对吗？

Access to XMLHttpRequest at 'https://...-api.herokuapp.com/api/contacts/question' from origin 'https://....com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.