Replace outdated ActiveModel::Serializers by Panko::Serializer

[casperisfine]

Most of the code was super easy to convert.

So far I've found one blocker:

• There's no way to conditionally include attributes. Best we can do is to have a null value.

I'll see if I can get that feature added upstream.

[casperisfine]

• There's no way to conditionally include attributes. Best we can do is to have a null value.

Upstream accepted the patch very quickly. There is still a minor limitation as it only work for regular attributes, relations can't be skipped. But I think it's probably fine. It just means a couple of API fields will be explicitly null rather than being skipped. I can live with that.

Overall the integration was super easy, I'm just a bit worried because the test coverage of the serializers is relatively limited, so It's not unlikely I missed some difference between the two serailizers.

[casperisfine]

Ok, so I found another big issue. Panko directly tries to reach into the Active Record attributes object, which means that overriden attribute methods, or even virtual attributes are not supported, e.g.

class Stack < AR::Base
  def repo_name
    repo.name
  end
end

class StackSerializer << Panko::Serializer
  attributes :repo_name
end

stack.repo_name # => "Some String"
StackSerializer.new.serailize(stack).to_json # => '{"repo_name": null}'

I think I can get this handled upstream, but ultimately I'm getting a bit uncomfortable with the panko_serializer implementation, that's a lot of C code that reach in Active Record internals, I'm kind of worried about its maintainability.

I might look for another gem.