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.



18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
# 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.klass if @many && @object.is_a?(ActiveRecord::Relation)
  @model ||= @object.first.class if @many &&
    @object.is_a?(Enumerable) &&
    @object.first.is_a?(ActiveRecord::Base)

  @model ||= @controller.class.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.



325
326
327
328
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 325

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

.[]=(key, value) ⇒ Object 



330
331
332
333
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 330

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.



314
315
316
317
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 314

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

#[]=(key, value) ⇒ Object 



319
320
321
322
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 319

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

#_associations_limit ⇒ Object

Get the associations limit from the controller.



115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 115

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.



136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 136

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`.



284
285
286
287
288
289
290
291
292
293
294
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 284

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 



39
40
41
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 39

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

#fields ⇒ Object 



43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 43

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.



102
103
104
105
106
107
108
109
110
111
112
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 102

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 



85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 85

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.



258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 258

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.



279
280
281
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 279

def get_serializer_config
  self.get_raw_serializer_config
end

#serialize(*args) ⇒ Object 



296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
 
# File 'lib/rest_framework/serializers/native_serializer.rb', line 296

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