Question

从本地主机启动服务器时，没有出现任何错误。但是部署到Heroku之后，它在某些特定路线上给了我以下cors错误：

No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:8080' is therefore not allowed access. The response had HTTP status code 503. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

我已经尝试了几乎所有方法来解决此错误，并且还尝试了在堆栈溢出时发现的所有可能解决方案，但是没有任何效果。

我的代码很简单：有一个登录功能可以向API端点发送请求，并且该端点可以确保管理员是否已通过身份验证。

我的服务器代码：（使用express js）

const expressApp = require('express');
const port = process.env.PORT || 3000;
const cors = require('cors');
const express = expressApp();

const bodyParser = require('body-parser');


const session = require('express-session');
const adminRoutes = require('./admin/admin-routes');
const userRoutes = require('./users/user-routes');
const bookingRoutes = require('./booking/booking-routes');
const contactRoutes = require('./contact-us/contact-routes');
require('./dbConnection.js');

express.use(function (req, res, next) {

    console.log(req.headers);
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
    res.header("Access-Control-Allow-Methods", "POST,DELETE,PUT,GET,OPTIONS");
    res.header("Access-Control-Allow-Headers", req.headers['access-control-request-headers']);
    res.header("Access-Control-Request-Method", req.headers['access-control-request-method']);
    next();
});

客户端是：

fetch(url, {  
        method: "POST",
        password: this.password,
        body: JSON.stringify({
            bodyData: { email }
        }),
        headers: {
            'Access-Control-Allow-Origin': '*',
            "Content-Type": "application/json"
        }

    }).then(res => {
        return res.json()
    }).then(user => {
         // somthing here 
    }).catch(error => {
        console.log(error);
    })

Heroku部署后出现错误“请求的资源上没有'Access-Control-Allow-Origin'标头”

0 个答案: