CODEWITHSUNDEEP
ruby-on-railsember.js
Derrick Camerino
Derrick Camerino

Reputation: 46

How to create a model and its associations in one request using Ember.js and Rails?

In ember.js/ember-data.js, is there a way to have the store POST to rails such that it sends information to create a model and its associations? Let me provide some context.

Suppose I have 3 rails models:

class Post < ActiveRecord::Base
  has_many :categorizations
  has_many :categories, :through => :categorizations

  attr_accessible :categories_attributes

  accepts_nested_attributes_for :categories
end

class Categories < ActiveRecord::Base
  has_many :categorizations
  has_many :posts, :through => :categorizations
end

class Categorizations < ActiveRecord::Base
  belongs_to :post
  belongs_to :categories
end

In ember.js, I want to be able to create a post along with its categorizations in one request. This is what I have done to achieve that:

App.Category = DS.Model.extend
  name: DS.attr 'string'

App.Categorization = DS.Model.extend
  post: DS.belongsTo 'App.Post'
  category: DS.belongsTo 'App.Category'

App.Post = DS.Model.extend
  title: DS.attr 'string'
  content: DS.attr 'string'
  categorizations: DS.hasMany 'App.Categorization',
    embedded: true
  toJSON: (options={}) ->
    options.associations = true
    @_super(options)


# meanwhile, somewhere else in code...

post = App.store.createRecord App.Post,
  title: "some title"
  content: "blah blah"

transaction = App.store.transaction()
categorization = transaction.createRecord App.Categorization,
  category: category # an instance of DS.Category

post.get('categorizations').pushObject categorization

# XXX: This enables ember-data to include categorizations in the post hash when
# POSTing to the server so that we can create a post and its categorizations in
# one request. This hack is required because the categorization hasn't been
# created yet so there is no id associated with it.
App.store.clientIdToId[categorization.get('clientId')] = categorization.toJSON()
transaction.remove(categorization)

App.store.commit()

I'm trying to make it so that when App.store.commit() is called it POSTs to /posts with something like:

{
  :post => {
    :title => "some title",
    :content => "blah blah,
    :categorizations => [ # or :categorizations_attributes would be nice
      {
        :category_id => 1
      } 
    ]
  }
}

Is there a way to achieve this without having ember POST to categorizations_controller to create the categorizations?

Upvotes: 2

Views: 558

Answers (1)

Peter Wagenet
Peter Wagenet

Reputation: 5056

You should take a look at what the RESTAdapter does with its bulkCommit option. The RESTAdapter is intended to work with Rails but you'll probably need to do a little bit of config on the Rails side to fully support it. See https://github.com/emberjs/data/blob/master/packages/ember-data/lib/adapters/rest_adapter.js

Upvotes: 1

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