Multipart requests with Angular

Question

So, i'm trying to post a multipart request with angular and the request payload dont match with my expectations. What i'm doing:

function sendBroadcastImage(ids, img) {
        var fd = new FormData();
        fd.append('destinationUsersIds', angular.toJson({
            values : ids
        }));
        fd.append('file', img);

        $http.post(
            '/some/api/url/',
            fd,
            {
                transformRequest: angular.identity,
                headers: { 'Content-Type': undefined }
            });
    }

I get this payload:

------WebKitFormBoundary3KBBZ9GEkqoGGQMC
Content-Disposition: form-data; name="destinationUsersIds"

{"values":[2235]}
------WebKitFormBoundary3KBBZ9GEkqoGGQMC
Content-Disposition: form-data; name="file"; filename="capacete.jpg"
Content-Type: image/jpeg


------WebKitFormBoundary3KBBZ9GEkqoGGQMC--

What payload I need (with content-type for the first boundary too):

------WebKitFormBoundary3KBBZ9GEkqoGGQMC
Content-Disposition: form-data; name="destinationUsersIds"
Content-Type: application/json

{"values":[2235]}
------WebKitFormBoundary3KBBZ9GEkqoGGQMC
Content-Disposition: form-data; name="file"; filename="capacete.jpg"
Content-Type: image/jpeg


------WebKitFormBoundary3KBBZ9GEkqoGGQMC--

Is it possible? How can I do it?

Answer 1

According to this guy and documentation of FormData, u can use Blob to append a field with specific content type.

var fd = new FormData();
formData.append('destinationUsersIds', new Blob([angular.toJson({
    values: ids
})], {
    type: "application/json"
}));

Let me know if this works for you.