Active_model_serializers: undefined method `embed'

[tommyblue]

I'm using the 0.10.0.rc1 version because 0.9.x doesn't work, but with this definition of the serializer:

class Api::V1::ItinerarySerializer < ActiveModel::Serializer
  attributes :id, :title

  embed :ids, include: true
  has_many :pois, serializer: Api::V1::PoiSerializer
end

I get this error:

NoMethodError (undefined method `embed' for Api::V1::ItinerarySerializer:Class):
  app/serializers/api/v1/itinerary_serializer.rb:4:in `<class:ItinerarySerializer>'
  app/serializers/api/v1/itinerary_serializer.rb:1:in `<top (required)>'
  app/controllers/api/v1/itineraries_controller.rb:29:in `update'

Embed is deprecated? How can I generate the "old" JSON including associated objects, like this:

{
  "itinerary": {
    "poi_ids": [1,4,5]
  },
  { "pois": [
    // POI serialized objects
  ]}
}

[groyoh]

I'm afraid that is not currently possible with 0.10. @joaomdmoura is this a planned feature for 0.10?
In the meantime, you could workaround it by creating your own adapter based on the json adapter. If you need some help with that let me know.

[tommyblue]

ok, thanks.
Shouldn't this an important option? I have an habtm association and embedding object is a good way to avoid data replication inside the single json response or avoiding multiple requests (one for each id).
Isn't it?

[joaomdmoura]

Hey @tommyblue, indeed, @groyoh is right!

Its possible to accomplish something close to it by using JSON-API, but would be a different implementation and not the '"old" JSON'.

btw why not use only:

 has_many :pois, serializer: Api::V1::PoiSerializer

This will return the serialized objects, isn't waht you need? You can map the ids if you want to, on a virtual attribute:

class Api::V1::ItinerarySerializer < ActiveModel::Serializer
  attributes :id, :title, : poi_ids
  has_many :pois, serializer: Api::V1::PoiSerializer

  def poi_ids
    object.pois.map {|p| p.id}
  end
end

[tommyblue]

If I'm not wrong, your solution puts the serialized POI objects inside their Itinerary "fathers". This means that there will be a lot of replicated POI objects inside different itineraries. This is not a problem with few objects but with a lot of objects is a lot of useless weigth into the JSON

[bf4]

@tommyblue Which adapter are you using? Json or JsonApi? You might want to subclass the adapter you're using to extend it.

[tommyblue]

@bf4 I could, but I'd like to understand from @joaomdmoura if I'm saying something wrong stating that the use of embed :ids, include: true is preferable when having a HABTM association with a lot of records since it can reduce the weight of the response.
I don't know the background discussion which led to removing embed, but I think it's useful so I'd like to understand why isn't present any more :)

thanks!

[joaomdmoura]

@tommyblue indeed I didn't realised the whole scenario. It makes sense.
Actually we haven't decided to remove embed, we just haven't implemented or discussed about it yet. :smile:

The good news is that I'm willing to review a PR implementing it, but the bad one is that I'm busy into some other new features, so we can't work on this right now, but we might do it in a near future!! :smile: Meanwhile @kurko do you have any thoughts about it?

[tommyblue]

thanks @joaomdmoura

[NullVoxPopuli]

side loading is the preferred method of retrieving data for ember.
it reduces redundancy when nested models would otherwise reference the same model.

for example, if your json references "tag" objects, you don't want to include the same tag data twice, so you just make an id reference.

[ZackMattor]

:+1: I also need this functionality... I'll probably have to roll back to 0.9 for now.

[NullVoxPopuli]

I'm going to work on this a bit today, as I absolutely NEED it for communicating with ember.

[NullVoxPopuli]

I have a pull request #1088 which I hope addresses this for most people

[NullVoxPopuli]

as for embedding ids only, would it make sense to have embed_ids: true on the associations declaration?

[ZackMattor]

Didn't v0.9 do it on the class level? But I do see the appeal of being able to change the behavior per association.

[mattholtom]

Here's my workaround for now, similar to @joaomdmoura above:

class PostSerializer < ActiveModel::Serializer
  attributes :id, :comment_ids

  def comment_ids
    object.comments.pluck(:id)
  end

end

[andrewhavens]

Sounds like #1127 added support for nested associations and #1084 is a work in progress, trying to introduce a backwards compatible "Legacy Adapter". As far as I know, embedding IDs is the default when using the JSON-API adapter. Just wanted to update the breadcrumb trail. =]

[bf4]

@andrewhavens about right. embed was terminology from an earlier iteration of the json api spec, iirc. Subclassing an adapter (and then sharing it!) would probably be the simplest way to have the exact same behavior

[NullVoxPopuli]

Closing for now --

It looks like there have been a couple different strategies for achieving the functionality of embed_ids, so further action could be in the form of a pull request, or expanding on the LegacyJSON PR, or something similar.

[aandis]

+1. This is a necessity for active-model-adapter. Would really like it back.

[bf4]

@aandis This macro won't be re-added as it was from an earlier iteration of JSON API see https://github.com/rails-api/active_model_serializers/issues/938#issuecomment-188129077

The docs you link to are because that repo hasn't been updated https://github.com/ember-data/active-model-adapter/issues/66

[Jarred-Sumner]

+1. I need this too.

[NullVoxPopuli]

some work on this is actually being done here: https://github.com/rails-api/active_model_serializers/pull/1845

[alexloginov]

+1. Need this too.

[NullVoxPopuli]

@alexloginov in the latest version of AMS, include be used from the render call :-)