non-cacheable fields

[deepsystm]

Hi ElMassimo, thanks for your work, amazing and fast lib!

I have a few questions:

1. How do I make fields in the serializer that are always obtained by querying a value rather than a cached version of the value?

class MixSerializer < Oj::Serializer
  has_one     :user, serializer: UserListItemSerializer

  attributes  :id, 
              :field_that_never_been_cached,
              :title


  attribute \
  def field_that_never_been_cached
    get_updated_data
  end

end

2. How to pass additional data to the serializer besides the serialization object itself? For example current_user object from Devise

render json: AlbumSerializer.one(album, current_user: current_user) if signed_in?

Thanks!

[ElMassimo]

Hi Vladimir! @deepsystm

---

How do I make fields in the serializer that are always obtained by querying a value rather than a cached version of the value?

By default, serializers do not cache any value, so every time the MixSerializer is used, it would call get_updated_data again.

If you share an example that's not working as expected in a public repo, I can take a look.

---

How to pass additional data to the serializer besides the serialization object itself?

Any additional options, such as current_user: current_user are available in an options hash:

class AlbumSerializer < Oj::Serializer
  def current_user
    options[:current_user]
  end
end

If it's something that you plan on using often, you can define helpers in a BaseSerializer.

Also, if the additional data is not optional, you might want to use fetch instead:

  def current_user
    options.fetch(:current_user)
  end

That way it will fail early if the serializer is used incorrectly.

[deepsystm]

Thanks a lot! It's quite well explained! No more questions 🥇

[deepsystm]

Hello, everyone!
I continue to use the library for development, it has shown great results in speed and ease of operation.

There is a question to continue the topic of passing parameters to the serializer:
How can I pass parameters when calling has_one and has_many in the serializer itself?

class MySerializer < Oj::Serializer

  has_one     :user, serializer: UserSerializer, my_parameter: options.fetch(:my_parameter, nil)

end


class UserSerializer < Oj::Serializer

  def my_parameter
    options.fetch(:my_parameter, nil)
  end

end

MySerializer.one(object, my_parameter: MY_VALUE)

when I try to do it, ruby says:

error at line 2: undefined local variable or method `options' for MySerializer:Class

I solve this this using something like:

class MySerializer < Oj::Serializer

  def user
       UserSerializer.one(object.user, my_parameter: MY_VALUE)
  end

end

But docs says:
The associations DSL is more concise and achieves better performance, so prefer to use it instead of manually definining attributes

[ElMassimo]

Hi Vladimir, glad it's been useful.

If you need to pass options, defining a method manually is the correct approach 👍

---

To clarify on that "performance note", the difference is that when using has_one and has_many it will reuse the same string writer, while when calling one or many manually it will create a new string writer. Even then, writing the contents of a string writer is very efficient, so the performance difference should be negligible in most use cases.

[deepsystm]

thanks! 👍