Backbone: CORS sync sends OPTIONS request instead of POST

Created on 17 May 2013  ·  17Comments  ·  Source: jashkenas/backbone

I'm trying to use the model.save() with a rest service on another subdomain. I got the following request headers which are far from my expectations:

OPTIONS /user HTTP/1.1
Host: not.public
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Origin: http://not.public
Access-Control-Request-Method: POST
Access-Control-Request-Headers: content-type
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache

How to fix this?

Ofc. my REST server responds 404 not found for an OPTIONS call...

To avoid unwanted questions: the server is ok, it handles REST calls and CORS calls well, tested with $.ajax and a REST interface tester application too.

Most helpful comment

@inf3rno try this one.

header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Headers: Content-Type');
header('Access-Control-Allow-Methods: POST');

This isn't Backbone issue at all.

All 17 comments

Look up how CORS works -- this is the expected "preflight" request

https://developer.mozilla.org/en-US/docs/HTTP/Access_control_CORS#Preflighted_requests

How can I avoid this reflight request?

Only be sending a "simple request" as defined here: https://developer.mozilla.org/en-US/docs/HTTP/Access_control_CORS#Simple_requests

I tried this on server side to handle preflight calls:

header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Headers: X-Requested-With');
header('Access-Control-Allow-Methods: POST, GET, PUT, DELETE, OPTIONS');

but did not work, the browser does not send another request after the preflight...

So you say that it is not possible with backbone.sync?
Then it is a bug I think...

Regardless, this isn't a Backbone issue, so I suggest asking on Stackoverflow or IRC.

Can you explain me why this is not a backbone issue?

Read through the source of Backbone.sync ( http://backbonejs.org/docs/backbone.html#section-134 ) and you'll see Backbone simply passes everything through to $.ajax.

@inf3rno try this one.

header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Headers: Content-Type');
header('Access-Control-Allow-Methods: POST');

This isn't Backbone issue at all.

These are my original headers without php:

HTTP/1.1 200 OK
Cache-Control: max-age=0, no-cache, no-store, must-revalidate
Pragma: no-cache
Content-Type: text/html
Expires: Wed, 11 Jan 1984 05:00:00 GMT
Server: Microsoft-IIS/7.5
X-Powered-By: PHP/5.3.8, ASP.NET
access-control-allow-origin: http://x.y.loc
Access-Control-Allow-Methods: POST, GET, PUT, DELETE, OPTIONS
Date: Fri, 17 May 2013 01:33:02 GMT
Content-Length: 0

I think my server is well configured, but I tried out the headers you gave, and they did not work...

Simple $.ajax calls work well, for example I load json files from the service with this:

define(function (require, exports, module) {
    var $ = require("jquery");

    module.exports = {
        load: function (name, _require, load, config) {
            var params = name.split("|");
            var method, url;
            if (params.length == 1) {
                method = "GET";
                url = params[0];
            }
            else {
                method = params[0];
                url = params[1];
            }
            $.ajax({
                url: url,
                type: method,
                dataType: "json"
            }).success(load).error(function (xhr, status, error) {
                    throw error;
                });
        }
    };

});

I tried out this with any request method, and they responded well...

The collection.fetch() works well too, I have problems only with the model.save() ...

I tried it this way, maybe I'm doing something wrong:

        var User = Backbone.Model.extend({
            urlRoot: Application.service.Authorization.User.create.url
        });
        var form = new UserForm({
            model: new User({
                email: "[email protected]",
                name: "test"
            })
        }).render();
        form.on("submit", function (user) {
            console.log(user.attributes);
            user.save(null, {
                success: function (model, response, options) {
                    console.log("success");
                },
                error: function (model, xhr, options) {
                    console.log("error");
                }
            });
        });

I got the attributes and "error" in console. I'll check what kind of error is..

You were right, thanks! I added to server config the allow content-type, and it works now. Firebug is not the best, the Chrome console printed that the content-type is not allowed...

Many tanks! :D

GET and POST requests requires quite different headers. When the API server uses cookies for authentication, the server should have Access-Control-Allow-Credentials: true header. And off course you need to make a XHR request with withCredentials: true on client-side. When the API server uses Authorization header for BasicAuth request, you don't need withCredential. Instead, the Access-Control-Allow-Headers need to include Authorization in this case, just like

header('Access-Control-Allow-Headers: Authorization, Content-Type');

Ah, it seems you solved the issue while I'm writing this.

Ye, thanks anyway, you helped a lot!

@inf3rno Thanks so much for the comment about Chrome giving better error messages than Firebug! That helped us solve the problem.

You're welcome! :-)

In case anyone else is having this problem I had to add "x-http-method-override" to my list of Access-Control-Allow-Methods which is used when you set Backbone.emulateHTTP = true

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