Node: CORS Fails Occasionally

问题

I have a node app with the server hosted on heroku. All my requests are successful until I have sent about 10 or 15. Then I start receiving CORS errors. Any idea why this could be occurring?

Give it a try. http://danielrasmuson.github.io/

Here is my 'CORS Enabling Code'. I'm trying a few things at this point.

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

app.all('/*', function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "*");
  res.header("Access-Control-Allow-Headers", "X-Requested-With");
  next();
});

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();
});

回答1:

I do know not if it is not too late but maybe this can help: I had the same problem with this code: (occasionally i got cors erros with 503 heroku error)

router.post('/create', function (req, res, next) {
    password(req.body.user_password).hash(function (error, hash) {
        if (error)
            throw new Error('Something went wrong!' + error)

        console.log(req.body);
        req.body.user_password = hash;
        User.create(req.body, function (err, post) {
            if (err) return next(err);
            console.log(post);
            res.json(post);
        });
    });

});

When I changed it to :

router.post('/create', function (req, res, next) {
    password(req.body.user_password).hash(function (error, hash) {
        if (error) {
            throw new Error('Something went wrong!' + error);
        } else {
            req.body.user_password = hash;
            User.create(req.body, function (err, post) {
                if (err) {
                    throw new Error('Something went wrong!' + err);
                } else {
                    res.json(post);
                }
            });
        }
    });

});

No more failing code and cors occasionally.

Finally it seems to be problem of node app and not heroku.

Cheers Blazej

来源：https://stackoverflow.com/questions/27157195/node-cors-fails-occasionally