Class: Fars::BaseCollectionSerializer

Inherits:
Object
  • Object
show all
Defined in:
lib/fars/base_collection_serializer.rb

Overview

Class: BaseCollectionSerializer

It is used to represent collection

Instance Method Summary collapse

Constructor Details

#initialize(objects, opts = {}, &block) ⇒ BaseCollectionSerializer

Constructor

Params:

- objects {ActiveRecord::Relation} or {Array} collection to serialize
- opts {Hash} of options:
  - fields {Array} of attributes to serialize. Can be {NilClass}.
    If so - will use all available.
  - scope {Object} context of request. Usually current user
    or current ability. Can be passed as a {Proc}. If so -
    evaluated only when actually called.
  - :add_metadata {Boolean} if to add a node '_metadata'
  - :root_key {Symbol} overwrites the default one from serializer's Class
  - :api_version {String} namespace for serializers classes, e.g. "V1"
  - :class_name {String} serialized model class name
  - :serializer {String} model serializer class name
  - :metadata {Hash} optional hash with metadata (root_key should not be false)



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# File 'lib/fars/base_collection_serializer.rb', line 25

def initialize(objects, opts = {}, &block)
  @objects = objects
  if !opts.has_key?(:root_key) && !opts[:class_name] && empty_array?
    raise ArgumentError, 'Specify :root_key or model :class_name for empty array.'
  end
  # Cann't use Hash#fetch here, becouse if root_key provided default_root_key method should not be called.
  @root_key = opts.has_key?(:root_key) ? opts[:root_key] : default_root_key
  if !@root_key && opts[:metadata]
    raise ArgumentError, 'Can not omit :root_key if provided :metadata'
  end
  # Serialized model class name.
  @class_name = opts[:class_name]
  if opts[:serializer]
    if opts[:serializer].is_a? Proc
      @item_serializer = opts[:serializer]
    else
      @item_serializer_class = opts[:serializer].constantize
    end
  elsif block_given?
    @item_serializer = block
  end
  @api_version = opts[:api_version]
  @params = opts[:params] || {}
  @metadata = opts[:metadata]
  # Do not need options if serialize items with proc.
  unless @item_serializer
    # Options for model serializer.
    @options = opts.slice(:scope, :fields, :add_metadata, :api_version, :params)
    # If root_key is false, do not transfer this option to the model serializer class.
    @options[:root_key] = item_root_key if @root_key
  end
end

Instance Method Details

#as_json ⇒ Object

Returns: Hash



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# File 'lib/fars/base_collection_serializer.rb', line 61

def as_json
  items = []

  unless empty_array?
    @item_serializer ||= item_serializer_class.new(nil, options)

    objects.each do |object|
      items << item_serializer.call(object)
    end
  end

  return items unless root_key

  hash = { root_key => items }
  hash[:_metadata] = metadata if metadata
  hash
end

#to_json ⇒ Object 



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# File 'lib/fars/base_collection_serializer.rb', line 79

def to_json
  MultiJson.dump(as_json)
end