Accessing meta information passed in a json server response

Question

I am using the Ember-Data Rest-Adapter and the JSON returned from my server looks basically like the one in the Active Model Serializers Documentation

{
  \"         


        

Answer 1

I think the immediate fix for you would be to attach totalCount to your model(recordArray), see this thread.

Another way to go would be to create your own adapter:

DS.Adapter.create({
  find: function (store, type, id) {
    $.ajax({
      url:      type.url,
      dataType: 'jsonp',
      context:  store,
      success:  function(response){
        this.load(type, id, response.data);
      }
    });
  },
  findAll: function(store, type) {
    $.ajax({
      url:      type.url,
      dataType: 'jsonp',
      context:  store,
      success:  function(response){
        this.loadMany(type, response.data);
      }
    });
  }
});

Response parameter in success callback in findAll method, should be an object that you need:

response: {
  meta: {
    totalCount: 10
  },
  posts: [{}, {}]
}

Hope this helps.

Answer 2

I figured out a way to access the meta information passed in a response. But unfortunately it really does not seem to be supported by ember-data out of the box and I am writing the meta information to a global variable that I am then accessing via bindings in the requesting controller.

I ended up customizing the serializer the RESTAdapter is using:

App.CustomRESTSerializer = DS.RESTSerializer.extend({
  extractMeta: function(loader, type, json) {
    var meta;
    meta = json[this.configOption(type, 'meta')];
    if (!meta) { return; }
    Ember.set('App.metaDataForLastRequest', meta);
    this._super(loader, type, json);
  }
});

App.Store = DS.Store.extend({
  revision: 11,
  adapter: DS.RESTAdapter.create({
    bulkCommit: false,
    serializer: App.CustomRESTSerializer
  })
});

I am aware that this is not particularly pretty and actually think that this is against what ember-data expects us to do but fot the time being it's working correctly.

I will try to get this working with ember-data in a better way and submit a pull request when it is working or open an issue on github when anybody else is interested in getting this to work.

If anybody finds a more clean solution to this please let me know.

Answer 3

I found a cleaner approach for extracting meta information from the server response with ember-data.

We have to tell the serializer which meta-information to expect (in this case pagination):

 App.serializer = DS.RESTSerializer.create();

 App.serializer.configure({ pagination: 'pagination' });

 App.CustomAdapter = DS.RESTAdapter.extend({
   serializer: App.serializer
 });

 App.Store = DS.Store.extend({
   adapter: 'App.CustomAdapter'
 });

After that every time the server sends a meta-property with a pagination object this object will be added to the store's TypeMaps property for the requested Model-Class.

For example with the following response:

  {
    'meta': {'pagination': { 'page': 1, 'total': 10 } },
    'posts':[
      ...
    ]
  }

The TypeMap for the App.Post-Model would include the pagination object after the posts have loaded.

You can't observe the TypeMaps-property of the store directly so I added an computed property to the PostsController to have access to the requests pagination meta information:

 App.PostsController = Ember.ArrayController.extend({
    pagination: function () {
      if (this.get('model.isLoaded')) {
        modelType = this.get('model.type');
        this.get('store').typeMapFor(modelType).metadata.pagination
      }
    }.property('model.isLoaded')
 });

I really don't think that's a great solution to the meta information problem but this is the best solution I was able to come up with yet with Ember-Data. Maybe this will be easier in the future.