Tuesday, 10 December 2013

Ember.js and Rails - pt 2/x

Ok, it's been a couple of weeks (this is not the only thing I'm working on) and not too much progress. Getting my head around Ember has been a nightmare, not helped at all by the fact it is a moving target, especially in the case of Ember-Data.
So much of a moving target that the whole thing shifted into RC mode.
So, a lot of changes have had to be made.

Die, Coffeescript, Die Die Die.

The other thing is I cannot express deeply enough my hatred of Coffeescript. It seems, well, pointless. It seems to be used to write Javascript and I really don't see any advantages over just writing Javascript. It is argued that it is smaller, but that is not really the point when it is unreadable.
It is like I say that I write my letters in Japanese, which will eventually be converted to English, because in Japanese I can use a single Kanji character to express a whole word or concept in English. The fact that you have to learn Japanese to accomplish something you could adequately do from the start is the killer.

So, I have ditched Coffeescript for now.

Ember Store

So, the store.js file now looks like this:

HorseFeeder.ApplicationAdapter = DS.RESTAdapter.extend({
    namespace: 'api/v1'

Lesson #1 - don't use DS.ActiveModelSerializer

If I put this line in:

HorseFeeder.ApplicationSerializer = DS.ActiveModelSerializer.extend({});

everything stops parsing. Even though I am using ActiveModelSerializer on the Rails side.


Routing has changed in Ember-Data. It's a little simpler, but, they got rid of the store object, which means that you can't call the store directly from Firebug.

Routes now look like this:

HorseFeeder.EventDaysIndexRoute = Ember.Route.extend({
  model: function() {
    return this.store.find('event_day');

HorseFeeder.EventDaysShowRoute = Ember.Route.extend({
  model: function(params) {
    obj = this.store.find('event_day', params.event_day_id);
 return obj;


Right now it looks like this (see 'current crisis points' below):

class EventDayIndexSerializer < ActiveModel::Serializer
  attributes :id, :day
  has_many :events, embed: :ids, key: :events

Note that if I don't do that key:  :events thing Ember doesn't see the objects.

Current Crisis Points

Right now the backend is spewing out data and the front end is taking it. i.e. I am doing what all the Ember tutorials on the web do. But that is not the real world. Here are a list of my current pain points

  1. When I send out a list of objects in an index call, I do not want to send out all their associations/children because that would mean basically dumping the whole database, right?! As all objects are related to each other in my model it is unmanageable and slow. I am fixing this right now by writing serializers that only dump out the object, not the children.
  2. If you do what I do above (with the limited data at the index level) I cannot figure out how to get Ember to reload the object on the 'show' so I can fill in all the data. To me this seems to be such an obvious way to do it I can't believe I've spent 2 days trying to get it to work.
  3. What doesn't the ActiveModelSerializer in Ember work for AMS in Rails?
  4. The pain and time so far have caused me to question the wisdom of using Ember!
I have a few open StackOverflow questions... so hopefully my next instalment will be all sweetness and light.

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