CORS政策如何在快递中妥善管理？

Question

I am trying to allow access from everywhere.

I have tried using app middleware:

app.use(function (req, res, next) {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader('Access-Control-Allow-Methods', '*');
  res.setHeader("Access-Control-Allow-Headers", "*");
  next();
});

I have tried using it in the route:

app.post('/login',function(req,res){
var login   = req.body;
var sess    = req.session;

if (!login.email && !login.pwd){    
    return res.status(401);
}
res.header("Access-Control-Allow-Origin", '*');
res.header("Access-Control-Allow-Headers", '*');
.... more code here

Both do not work. I keep getting an error: "Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource."

Further down the server, we use similar code for another route, which works:

app.post('/questar',function(req,res){
//allow xhr post from retireup domains
var cors = {
    origin: "https://www.website.com";
};
res.header("Access-Control-Allow-Origin", cors.origin);
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.type('application/json');

I cannot tell the difference between the code, but only one set works. Any ideas why? This seems like an issue that shouldn't be so complicated. Thanks

Answer 1

After applying "cors" middleware. You should be passed "http://" before "localhost:". in url send to by Axios like this:

axios.get("http://localhost:8080/api/getData")
.then(function (response) {
this.items= response.data;
}).catch(function (error) {
console.log(error)
});

Answer 2

MDN has a very short explanation on how a server should respond to a Preflight Request .

You handle CORS preflight requests by handling the HTTP OPTIONS method (just like you would handle GET and POST methods) before handling other request methods on the same route:

app.options('/login', ...);
app.get('/login'. ...);
app.post('/login'. ...);

In your case, it might be as simple as changing your app.use() call to app.options() , passing the route as the first argument, setting the appropriate headers, then ending the response:

app.options('/login', function (req, res) {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader('Access-Control-Allow-Methods', '*');
  res.setHeader("Access-Control-Allow-Headers", "*");
  res.end();
});
app.post('/login', function (req, res) {
  ...
});

Answer 3

Configure the CORS stuff before your routes, not inside them.

Here, like this (from enable-cors.org ):

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();
});

app.get('/', function(req, res, next) {
  // Handle the get for this route
});

app.post('/', function(req, res, next) {
 // Handle the post for this route
});

I always configure it like this in my Express+Angular apps and it works just fine.

Hope it helps.

Answer 4

First install, the "cors" package from npm: npm i -S cors

Then enable it in your express server.

var express = require('express'),
  cors = require('cors');

const app = express();
app.use(cors());

...

Answer 5

Following other's answers, this worked for me:

res.setHeader("Access-Control-Allow-Origin", 'http://myDomain:8080');
res.setHeader('Access-Control-Allow-Methods', 'POST,GET,OPTIONS,PUT,DELETE');
res.setHeader('Access-Control-Allow-Headers', 'Content-Type,Accept');

Answer 6

Following some standard node projects out there, below CORS configuration worked for me always. It requires the npm package 'cors'. Note: Origin * means enabling responses to any origin and replies with status code 200. If this needs to be limited to one domain, update the origin accordingly. Ex: [origin: ' http://exampleui.com ']

var cors = require('cors');
var corsOptions = {
    origin: '*',
    optionsSuccessStatus: 200,
  }
app.use(cors(corsOptions));
app.use(express.json())

Answer 7

All you have to whitelist the domains name to avoid getting cors error messages.

There is a plugin called cors , installed it into your project using this command

npm i cors

after installing use this code to remove the cors related errors form your project.

const cors = require('cors');

const corsOption = {
    credentials: true,
    origin: ['http://localhost:3000', 'http://localhost:80']
}

app.use(cors(corsOption));

In the origin section you can pass any domain to whitelist it. If you want to whitelist all the domain names, instead of passing the the urls array. you can pass '*' over there.

Example: origin: '*'

credentials: Configures the Access-Control-Allow-Credentials CORS header. Set to true to pass the header, otherwise it is omitted.