Ember Data serialize relationship without parent ID

Question

I'm building an adapter to wrap the Keen.io API, so far I've been able to successfully load the projects resource, however the returned object looks like this:

{
  partners_url: "/3.0/projects/<ID>/partners",
  name: "Project Name",
  url: "/3.0/projects/<ID>",
  saved_queries: [ ],
  events_url: "/3.0/projects/<ID>/events",
  id: "<ID>",
  organization_id: "<ORG ID>",
  queries_url: "/3.0/projects/<ID>/queries",
  api_key: "<API KEY>",
  events: [
    {
      url: "/3.0/projects/<ID>/events/user_signup",
      name: "user_signup"
    },
    {
      url: "/3.0/projects/<ID>/events/user_converted",
      name: "user_converted"
    },
    {
      url: "/3.0/projects/<ID>/events/user_created_project",
      name: "user_created_project"
    }
  ]
}

Excluding a lot of cruft, Ember has no trouble mapping the name and id attributes using the RESTSerializer, but if I add an events relation to my Project model it blows up with:

Error while loading route: TypeError: Cannot set property 'store' of undefined
    at Ember.Object.extend.modelFor (http://localhost:3000/assets/ember-data.js?body=1:9813:23)
    at Ember.Object.extend.recordForId (http://localhost:3000/assets/ember-data.js?body=1:9266:21)
    at deserializeRecordId (http://localhost:3000/assets/ember-data.js?body=1:10197:27)
    at deserializeRecordIds (http://localhost:3000/assets/ember-data.js?body=1:10211:9)
    at http://localhost:3000/assets/ember-data.js?body=1:10177:11
    at http://localhost:3000/assets/ember-data.js?body=1:8518:20
    at http://localhost:3000/assets/ember.js?body=1:3404:16
    at Object.OrderedSet.forEach (http://localhost:3000/assets/ember.js?body=1:3247:10)
    at Object.Map.forEach (http://localhost:3000/assets/ember.js?body=1:3402:10)
    at Function.Model.reopenClass.eachRelationship (http://localhost:3000/assets/ember-data.js?body=1:8517:42)

From my investigation this seems to be because it can't find the inverse relation to map an Event back to a Project because there's no parent ID.

Is it possible to create a relation in Ember Data to support this? Or is it possible to modify the Serializer to append a projectId to each event before loading?

I'm using Ember 1.5.0-beta.4 and Ember Data 1.0.0-beta.7+canary.f482da04.

Flo Flo · Accepted Answer · 2014-03-16T21:00:16

Assuming your Project model is setup the following way:

App.Project = DS.Model.extend({
  events: DS.hasMany('event');
});

You need to make sure that the JSON from your API is in a certain shape that Ember-Data expects.

{
  "project": {
    "id": 1,
    "events": ["1", "2"],
  },

  "events": [{
    "id": "1",
    "name": "foo"
  }, {
    "id": "2",
    "name": "bar"
  }]
}

You can, however, implement extractArrayin your model's serializer to transform the JSON from the server into something similar like the above example.

There's a working example and an explanation in the Ember docs.

Ember Data serialize relationship without parent ID

1 Answers