mirror of
https://github.com/ditkrg/active_model_serializers.git
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d7de53ce30
For discussion: Consider evaluating association in serializer context That way, associations are really just anything that can be conditionally included. They no longer have to actually be methods on the object or serializer. e.g. ```diff has_many :comments do - last(1) + Comment.active.for_serialization(object).last(1) end ```
93 lines
3.4 KiB
Ruby
93 lines
3.4 KiB
Ruby
module ActiveModel
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class Serializer
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# Holds all the meta-data about an association as it was specified in the
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# ActiveModel::Serializer class.
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#
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# @example
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# class PostSerializer < ActiveModel::Serializer
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# has_one :author, serializer: AuthorSerializer
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# has_many :comments
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# has_many :comments, key: :last_comments do
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# object.comments.last(1)
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# end
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# end
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#
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# Notice that the association block is evaluated in the context of the serializer.
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# Specifically, the association 'comments' is evaluated two different ways:
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# 1) as 'comments' and named 'comments'.
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# 2) as 'object.comments.last(1)' and named 'last_comments'.
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#
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# PostSerializer._reflections #=>
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# # [
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# # HasOneReflection.new(:author, serializer: AuthorSerializer),
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# # HasManyReflection.new(:comments)
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# # ]
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#
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# So you can inspect reflections in your Adapters.
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#
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Reflection = Struct.new(:name, :options, :block) do
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# @api private
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def value(instance)
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if block
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instance.instance_eval(&block)
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else
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instance.read_attribute_for_serialization(name)
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end
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end
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# Build association. This method is used internally to
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# build serializer's association by its reflection.
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#
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# @param [Serializer] subject is a parent serializer for given association
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# @param [Hash{Symbol => Object}] parent_serializer_options
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#
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# @example
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# # Given the following serializer defined:
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# class PostSerializer < ActiveModel::Serializer
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# has_many :comments, serializer: CommentSummarySerializer
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# end
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#
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# # Then you instantiate your serializer
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# post_serializer = PostSerializer.new(post, foo: 'bar') #
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# # to build association for comments you need to get reflection
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# comments_reflection = PostSerializer._reflections.detect { |r| r.name == :comments }
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# # and #build_association
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# comments_reflection.build_association(post_serializer, foo: 'bar')
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#
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# @api private
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#
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def build_association(subject, parent_serializer_options)
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association_value = value(subject)
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reflection_options = options.dup
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serializer_class = subject.class.serializer_for(association_value, reflection_options)
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if serializer_class
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begin
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serializer = serializer_class.new(
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association_value,
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serializer_options(subject, parent_serializer_options, reflection_options)
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)
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rescue ActiveModel::Serializer::CollectionSerializer::NoSerializerError
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reflection_options[:virtual_value] = association_value.try(:as_json) || association_value
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end
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elsif !association_value.nil? && !association_value.instance_of?(Object)
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reflection_options[:virtual_value] = association_value
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end
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Association.new(name, serializer, reflection_options)
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end
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private
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def serializer_options(subject, parent_serializer_options, reflection_options)
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serializer = reflection_options.fetch(:serializer, nil)
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serializer_options = parent_serializer_options.except(:serializer)
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serializer_options[:serializer] = serializer if serializer
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serializer_options[:serializer_context_class] = subject.class
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serializer_options
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end
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end
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end
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end
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