Question

我正在使用运行的NodeJS应用，

http://localhost:3000

我还有一个http://localhost:3002上运行的NodeJS API。

我在应用程序中调用API时收到以下错误。

Failed to load http://localhost:3002: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:3000' is therefore not allowed access.

我已在server.js的{{1}}文件中添加了CORS

http://localhost:3002

我仍然收到错误消息。每当我打开URL http://localhost:3000时，我都会在chrome开发者控制台中看到错误。

Answer 1

您应该像这样使用cors

app.use(cors());

参考

Simple Usage (Enable All CORS Requests)

var express = require('express')
var cors = require('cors')
var app = express()

app.use(cors())

app.get('/products/:id', function (req, res, next) {
  res.json({msg: 'This is CORS-enabled for all origins!'})
})

app.listen(80, function () {
  console.log('CORS-enabled web server listening on port 80')
})

Answer 2

首先尝试

npm install cors
app.use(cors())

如果它不起作用，那么试试这个

allowCrossDomain = function(req, res, next) {
  res.header('Access-Control-Allow-Credentials', true);
  res.header('Access-Control-Allow-Origin', req.headers.origin);
  res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE');
  res.header('Access-Control-Allow-Headers', 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept');
  if ('OPTIONS' === req.method) {
    res.sendStatus(200);
  } else {
    next();
  }
};

app.use(allowCrossDomain);

NodeJS中的请求资源上不存在“ Access-Control-Allow-Origin”标头

2 个答案: