在 Express 应用程序中添加参数时出现 CORS 错误

Question

I can't at all figure out why this is not working.

I have an express app hosted on Heroku that basically does this

var urlMetadata = require('url-metadata')

var express = require('express')

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

app.use(cors())

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

app.get('/prod/:url', function (req, res, next) {

    var url = decodeURI(req.params.url);

    urlMetadata(url).then(
        function (metadata) {
            res.json({
                metadata
            });
        },
        function (error) {
            console.log(error)
        })
})

Client side

    axios
      .get(`https://git.heroku.com/egosmos-meta.git/prod`, {
        params: {
          url,
        },
      })
      .then((response) => {
        console.log(response);
      });

    axios
      .get(`https://egosmos-meta.herokuapp.com/products`)
      .then((response) => {
        console.log(response);
      });

And this is what I'm getting

So /products works, but /prod/:url throws a CORS error

Thanks for your help!

Answer 1

params in Axios defines the query parameters, eg ?url=http://example.com but your Express app is expecting a route parameter .

Change your client-side code to the following

axios.get(`https://git.heroku.com/egosmos-meta.git/prod/${encodeURIComponent(url)}`)

You get a CORS error because you have no route for /prod?url=... so the CORS middleware isn't kicking in.

Answer 2

try using the corsOption..

var cors = require('cors')

var corsOptions = { origin: 'https://git.heroku.com', optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204 }

app.use(cors(corsOptions))

Also if for the axios try axios.get( https://git.heroku.com/egosmos-meta.git/prod/${url} ).then()