How to create a record (in ember.js) with belongsTo relationship and persist it in django via tastypie?

So I am doing a chat application (frontend in ember.js and backend in django) which of course has to send messages.

My message model in ember.js looks like this:

Messages.Message = DS.Model.extend({
    body: attr('string'),
    user: DS.belongsTo('user'),
    time: attr('date'),
    recipient: DS.belongsTo('recipient'),
});

I tried to create and persist new message using code from this example: http://emberjs.com/guides/models/creating-and-deleting-records/

so my saveMessage action in controller looks like this:

var store = this.store;

var message = store.createRecord('message', {
    body: 'Lorem ipsum'
});

store.find('recipient', 2).then(function(recipient) {
    message.set('recipient', recipient);
});

message.save();

but the generated JSON`s attribute 'recipient' is null, so server returns error 500 because this field cannot by blank.

JSON should looks like:

{'body': 'loremipsum', 'recipient': {'username','some name'}, 'time': null, 'user': null}

Do you have an idea how to do this?

Solution

find is asynchronous, and returns a promise. That means the anonymous function passed to the then can likely be executed after you've called save. Move the save inside the then so that the recipient has been attached before saving.

var store = this.store;

var message = store.createRecord('message', {
    body: 'Lorem ipsum'
});

store.find('recipient', 2).then(function(recipient) {
    message.set('recipient', recipient);
    message.save();
});