Serializing errors

[remear]

The JSON API docs currently state (I'm not sure if they said this before JSON API 1.0):

A document MUST contain at least one of the following top-level members:

data: containing the document's "primary data"
errors: containing an array of error objects
meta: non-standard meta-information.

The members data and errors MUST NOT coexist in the same document.

Is there a way to render the errors member in master / v0.10.0.rc1?

[joaomdmoura]

@remear it's a implementation of 1.0
We haven't updated AMS yet, the actual supported version is RC4, we might update it this week but don't take it for granted 😄

[remear]

Great! Would it be possible to leave this issue open until it's resolved and reference it in commits so others can follow along. I'd love to help test this as soon as it becomes available.

[bf4]

I think what you want here is pseudo-code

if success
  render json: model
else
  render json: model.errors, root: "errors" # or maybe roll-your own error serializer and model.  Just mix in ActiveModel::Serialization
end

right?

[remear]

That's one way. For a rough example, what if I wanted to do this from rack with:

def respond_400(errors)
  serializer = ActiveModel::Serializer::ArraySerializer.new(errors, serializer: ErrorSerializer)
  response = ActiveModel::Serializer::Adapter.create(serializer).to_json
  [400, {'Content-Type' => 'application/vnd.api+json'}, [response]]
end

I wasn't sure how to get root in there.

[bf4]

Oh. you probably don't want to do that for a couple of reasons

1. it's not the intended usage and will only cause pain (in my experience)
2. it might be more happy path to have an error controller that you call directly here, e.g. ErrorsController.action(:show).call(env.merge(something)) (this will skip the rest of the call stack, see actioncontroller::metal
3. If you follow the code in

   active_model_serializers/lib/action_controller/serialization.rb

   Lines 38 to 48 in 460150f

   	@_adapter_opts, @_serializer_opts =
   	options.partition { |k, _| ADAPTER_OPTION_KEYS.include? k }.map { |h| Hash[h] }
   	if use_adapter? && (serializer = get_serializer(resource))
   	@_serializer_opts[:scope] ||= serialization_scope
   	@_serializer_opts[:scope_name] = _serialization_scope
   	# omg hax
   	object = serializer.new(resource, @_serializer_opts)
   	adapter = ActiveModel::Serializer::Adapter.create(object, @_adapter_opts)

   you'll have a happier time

[Jeehut]

Following @bf4's suggestion the structure still isn't in accordance with the JSON API specifications example and suggested structure. Here's an example structure from jsonapi.org:

{
  "errors": [
    {
      "status": "422",
      "source": { "pointer": "/data/attributes/first-name" },
      "title":  "Invalid Attribute",
      "detail": "First name must contain at least three characters."
    }
  ]
}

Using the following code I can still follow the JSON API requirements but it still isn't even close to the suggested structure above, which would be much more powerful:

if object.save
  render json: object, status: :created, location: object
else
  render json: { errors: object.errors }, status: :unprocessable_entity
end

Example error output:

{
  "errors": {
    "first_name": ["can't be blank", "is too short (minimum is 3 characters)", "is invalid"]
  }
}

I'd love to see this be part of this gem before Release of 0.10! 👍

[bf4]

@Dschee see #1004

[Jeehut]

@bf4: Thank you, looks like good progress. I'm currently using the https://github.com/joaomdmoura/active_model_serializers/tree/deserializer-implementation branch though since I really need the deserializers, so I will have to wait until both come to complete fruition and get merged.

I might be mistaken but my feeling when reading through the other threads was that this issue is either already solved or a duplicate, isn't it?

[bf4]

@Dschee I would say it can be done, just not explicitly supported, esp JsonApi, that's more work. In fact, it led me to create a json api errors examples on their examples page.. which is also why so many of the features are still unchecked in that pr :)

For rehydrating, take a look at some of the libs on http://jsonapi.org/implementations/