即使我在服务器上允许它,Socket.io 也会出现 CORS 错误 [英] Socket.io gives CORS error even if I allowed cors it on server
问题描述
我的节点服务器和客户端运行在不同的端口上(分别为 3001,5347).在我使用过的客户端上,
My node server and client are running on different ports(3001,5347 respectively). On client I had used,
var socket = io('http://127.0.0.1:3001');
在服务器上我一一尝试了所有的
On server I tried all of following one by one
1) io.set('origins', '*:*');
2) io.set('origins', 'http://127.0.0.1:5347');
3) io.set('origins', '*');
4) io.set('origins', '127.0.0.1:5347');
但我收到以下错误:
XMLHttpRequest 无法加载 http://127.0.0.1:3001/socket.io/?EIO=3&transport=polling&t=1456799439856-4590.当凭证标志为真时,不能在Access-Control-Allow-Origin"标头中使用通配符*".因此不允许访问 Origin 'null'.
XMLHttpRequest cannot load http://127.0.0.1:3001/socket.io/?EIO=3&transport=polling&t=1456799439856-4590. A wildcard '*' cannot be used in the 'Access-Control-Allow-Origin' header when the credentials flag is true. Origin 'null' is therefore not allowed access.
注意:我在服务器上使用 express,并且我已经通过以下方式使用 cors 中间件:
Note: I'm using express on server and I'm already using cors middleware in following way:
app.use(cors());
其中 app 和 cors 分别是 express 和 cors 的实例.
Where app and cors are instances of express and cors respectively.
推荐答案
如果运行Express如下:
If running Express as follows:
var app = express();
var server = app.listen(3000);
所以要启动socket.io,我们可以这样做:
So to start socket.io, we can do the following:
var io = require('socket.io').listen(server);
问题是因为以下代码:
var http = require('http').Server(app);
var io = require('socket.io')(http);
传递给 socket.io 的服务器对象与我正在监听的服务器对象不同.
The server object passed to socket.io was not the same as the server object I'm listening on.
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