Class: RESTFramework::Serializers::NativeSerializer

Inherits:
BaseSerializer show all
Defined in:
lib/rest_framework/serializers/native_serializer.rb

Overview

This serializer uses .serializable_hash to convert objects to Ruby primitives (with the top-level being either an array or a hash).

Constant Summary collapse

EXTRACT_FROM_QUERY = 
->(p, controller) {
  return Set[] if p.blank?
  (
    controller.request&.query_parameters&.[](p).presence&.split(",")&.map { |x|
      x.strip.presence
    }&.compact || []
  ).to_set
}

Instance Attribute Summary

Attributes inherited from BaseSerializer

#object

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from BaseSerializer

#associations, cache_enabled?, fragment_cache_enabled?, #serializable_hash

Constructor Details

#initialize(object = nil, *args, many: nil, model: nil, **kwargs) ⇒ NativeSerializer

Accept/ignore ‘*args` to be compatible with the `ActiveModel::Serializer#initialize` signature.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 18

def initialize(object = nil, *args, many: nil, model: nil, **kwargs)
  super(object, *args, **kwargs)

  if many.nil?
    # Determine if we are dealing with many objects or just one.
    @many = @object.is_a?(Enumerable)
  else
    @many = many
  end

  # Determine model either explicitly, or by inspecting @object or @controller.
  @model = model
  @model ||= @object.class if @object.is_a?(ActiveRecord::Base)
  @model ||= @object[0].class if
    @many && @object.is_a?(Enumerable) && @object.is_a?(ActiveRecord::Base)

  @model ||= @controller.class.get_model if @controller
end

Class Method Details

.[](key) ⇒ Object

Allow a serializer class to be used as a hash directly in a nested serializer config.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 323

def self.[](key)
  @_nested_config ||= self.new.get_serializer_config
  @_nested_config[key]
end

.[]=(key, value) ⇒ Object 



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 328

def self.[]=(key, value)
  @_nested_config ||= self.new.get_serializer_config
  @_nested_config[key] = value
end

Instance Method Details

#[](key) ⇒ Object

Allow a serializer instance to be used as a hash directly in a nested serializer config.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 312

def [](key)
  @_nested_config ||= self.get_serializer_config
  @_nested_config[key]
end

#[]=(key, value) ⇒ Object 



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 317

def []=(key, value)
  @_nested_config ||= self.get_serializer_config
  @_nested_config[key] = value
end

#_associations_limit ⇒ Object

Get the associations limit from the controller.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 113

def _associations_limit
  return @_associations_limit if defined?(@_associations_limit)

  limit = @controller&.class&.native_serializer_associations_limit

  # Extract the limit from the query parameters if it's set.
  if query_param = @controller&.class&.native_serializer_associations_limit_query_param
    if @controller.request.query_parameters.key?(query_param)
      query_limit = @controller.request.query_parameters[query_param].to_i
      if query_limit > 0
        limit = query_limit
      else
        limit = nil
      end
    end
  end

  @_associations_limit = limit
end

#_get_controller_serializer_config ⇒ Object

Get a serializer configuration from the controller. ‘@controller` and `@model` must be set.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 134

def _get_controller_serializer_config
  columns = []
  includes = {}
  methods = []
  serializer_methods = {}

  # We try to construct performant queries using Active Record's `includes` method. This is
  # sometimes impossible, for example when limiting the number of associated records returned, so
  # we should only add associations here when it's useful, and using the `Bullet` gem is helpful
  # in determining when that is the case.
  includes_map = {}

  column_names = @model.column_names
  reflections = @model.reflections
  attachment_reflections = @model.attachment_reflections

  self.fields.each do |f|
    field_config = @controller.class.field_configuration[f]
    next if field_config[:write_only]

    if f.in?(column_names)
      columns << f
    elsif ref = reflections[f]
      sub_columns = []
      sub_methods = []
      field_config[:sub_fields].each do |sf|
        if !ref.polymorphic? && sf.in?(ref.klass.column_names)
          sub_columns << sf
        else
          sub_methods << sf
        end
      end
      sub_config = { only: sub_columns, methods: sub_methods }

      # Apply certain rules regarding collection associations.
      if ref.collection?
        # If we need to limit the number of serialized association records, then dynamically add a
        # serializer method to do so.
        if limit = self._associations_limit
          serializer_methods[f] = f
          self.define_singleton_method(f) do |record|
            next record.send(f).limit(limit).as_json(**sub_config)
          end

          # Disable this for now, as it's not clear if this improves performance of count.
          #
          # # Even though we use a serializer method, if the count will later be added, then put
          # # this field into the includes_map.
          # if @controller.class.native_serializer_include_associations_count
          #   includes_map[f] = f.to_sym
          # end
        else
          includes[f] = sub_config
          includes_map[f] = f.to_sym
        end

        # If we need to include the association count, then add it here.
        if @controller.class.native_serializer_include_associations_count
          method_name = "#{f}.count"
          serializer_methods[method_name] = method_name
          self.define_singleton_method(method_name) do |record|
            next record.send(f).count
          end
        end
      else
        includes[f] = sub_config
        includes_map[f] = f.to_sym
      end
    elsif @controller.class.enable_action_text && ref = reflections["rich_text_#{f}"]
      # ActionText Integration: Define rich text serializer method.
      includes_map[f] = :"rich_text_#{f}"
      serializer_methods[f] = f
      self.define_singleton_method(f) do |record|
        next record.send(f).to_s
      end
    elsif @controller.class.enable_active_storage && ref = attachment_reflections[f]
      # ActiveStorage Integration: Define attachment serializer method.
      if ref.macro == :has_one_attached
        serializer_methods[f] = f
        includes_map[f] = { "#{f}_attachment": :blob }
        self.define_singleton_method(f) do |record|
          attached = record.send(f)
          next attached.attachment ? {
            filename: attached.filename,
            signed_id: attached.signed_id,
            url: attached.url,
          } : nil
        end
      elsif ref.macro == :has_many_attached
        serializer_methods[f] = f
        includes_map[f] = { "#{f}_attachments": :blob }
        self.define_singleton_method(f) do |record|
          # Iterating the collection yields attachment objects.
          next record.send(f).map { |a|
            {
              filename: a.filename,
              signed_id: a.signed_id,
              url: a.url,
            }
          }
        end
      end
    elsif @model.method_defined?(f)
      methods << f
    else
      # Assume anything else is a virtual column.
      columns << f
    end
  end

  {
    only: columns,
    include: includes,
    methods: methods,
    serializer_methods: serializer_methods,
    includes_map: includes_map,
  }
end

#_serialize(record, config, serializer_methods) ⇒ Object

Serialize a single record and merge results of serializer_methods.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 282

def _serialize(record, config, serializer_methods)
  # Ensure serializer_methods is either falsy, or a hash.
  if serializer_methods && !serializer_methods.is_a?(Hash)
    serializer_methods = [ serializer_methods ].flatten.map { |m| [ m, m ] }.to_h
  end

  # Merge serialized record with any serializer method results.
  record.serializable_hash(config).merge(
    serializer_methods&.map { |m, k| [ k.to_sym, self.send(m, record) ] }.to_h,
  )
end

#action ⇒ Object 



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 37

def action
  @action ||= @controller&.action_name&.to_sym
end

#fields ⇒ Object 



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 41

def fields
  return @fields if defined?(@fields)
  return nil unless base_fields = @controller&.get_fields

  only_param = @controller.class.native_serializer_only_query_param
  except_param = @controller.class.native_serializer_except_query_param
  include_param = @controller.class.native_serializer_include_query_param
  exclude_param = @controller.class.native_serializer_exclude_query_param

  only = EXTRACT_FROM_QUERY.call(only_param, @controller)
  except = EXTRACT_FROM_QUERY.call(except_param, @controller)
  include = EXTRACT_FROM_QUERY.call(include_param, @controller)
  exclude = EXTRACT_FROM_QUERY.call(exclude_param, @controller)

  field_configuration = @controller.class.field_configuration
  @fields = base_fields.select do |f|
    cfg = field_configuration[f]

    # We never serialize write-only fields.
    next false if cfg[:write_only]

    # We never serialize `hidden_from_index` fields for collections as this is a performance
    # option.
    next false if cfg[:hidden_from_index] && @many

    # Explicitly excluded fields should never be serialized.
    next false if f.in?(except) || f.in?(exclude)

    # Hidden fields must be in `only` or `include` to be serialized; for non-hidden fields, either
    # `only` must be empty, or the field must be in `only` or `include`.
    if cfg[:hidden]
      next true if f.in?(only) || f.in?(include)
    elsif only.empty? || f.in?(only) || f.in?(include)
      next true
    end

    next false
  end

  @fields
end

#get_controller_native_serializer_config ⇒ Object

Get a native serializer configuration from the controller.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 100

def get_controller_native_serializer_config
  return nil unless @controller

  if @many == true
    controller_serializer = @controller.class.native_serializer_plural_config
  elsif @many == false
    controller_serializer = @controller.class.native_serializer_singular_config
  end

  controller_serializer || @controller.class.native_serializer_config
end

#get_local_native_serializer_config ⇒ Object 



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 83

def get_local_native_serializer_config
  if (action = self.action) && (cfg = action_config)
    # Index action should use :list serializer config if :index is not provided.
    action = :list if action == :index && !cfg.key?(:index)

    return cfg[action] if cfg[action]
  end

  # No action_config, so try singular/plural config if explicitly instructed to via @many.
  return self.plural_config if @many == true && self.plural_config
  return self.singular_config if @many == false && self.singular_config

  # Lastly, try returning the default config.
  self.config
end

#get_raw_serializer_config ⇒ Object

Get the raw serializer config, prior to any adjustments from the request.

Use deep_dup on any class mutables (array, hash, etc) to avoid mutating class state.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 256

def get_raw_serializer_config
  # Return a locally defined serializer config if one is defined.
  if local_config = self.get_local_native_serializer_config
    return local_config.deep_dup
  end

  # Return a serializer config if one is defined on the controller.
  if serializer_config = self.get_controller_native_serializer_config
    return serializer_config.deep_dup
  end

  # If the config wasn't determined, build a serializer config from controller fields.
  if @model && self.fields
    return self._get_controller_serializer_config
  end

  # By default, pass an empty configuration, using the default Rails serializer.
  {}
end

#get_serializer_config ⇒ Object

Get a configuration passable to serializable_hash for the object.



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 277

def get_serializer_config
  self.get_raw_serializer_config
end

#serialize(*args) ⇒ Object 



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# File 'lib/rest_framework/serializers/native_serializer.rb', line 294

def serialize(*args)
  config = self.get_serializer_config
  serializer_methods = config.delete(:serializer_methods)
  includes_map = config.delete(:includes_map)

  if @object.respond_to?(:to_ary)
    # Preload associations using `includes` to avoid N+1 queries. For now this also allows filter
    # backends to use associated data; perhaps it may be wise to have a system in place for
    # filters to preload their own associations?
    @object = @object.includes(*includes_map.values) if includes_map.present?

    return @object.map { |r| self._serialize(r, config, serializer_methods) }
  end

  self._serialize(@object, config, serializer_methods)
end