vendor/rails/activerecord/lib/active_record/serialization.rb

   1 module ActiveRecord #:nodoc:
   2   module Serialization
   3     class Serializer #:nodoc:
   4       attr_reader :options
   5
   6       def initialize(record, options = {})
   7         @record, @options = record, options.dup
   8       end
   9
  10       # To replicate the behavior in ActiveRecord#attributes,
  11       # <tt>:except</tt> takes precedence over <tt>:only</tt>.  If <tt>:only</tt> is not set
  12       # for a N level model but is set for the N+1 level models,
  13       # then because <tt>:except</tt> is set to a default value, the second
  14       # level model can have both <tt>:except</tt> and <tt>:only</tt> set.  So if
  15       # <tt>:only</tt> is set, always delete <tt>:except</tt>.
  16       def serializable_attribute_names
  17         attribute_names = @record.attribute_names
  18
  19         if options[:only]
  20           options.delete(:except)
  21           attribute_names = attribute_names & Array(options[:only]).collect { |n| n.to_s }
  22         else
  23           options[:except] = Array(options[:except]) | Array(@record.class.inheritance_column)
  24           attribute_names = attribute_names - options[:except].collect { |n| n.to_s }
  25         end
  26
  27         attribute_names
  28       end
  29
  30       def serializable_method_names
  31         Array(options[:methods]).inject([]) do |method_attributes, name|
  32           method_attributes << name if @record.respond_to?(name.to_s)
  33           method_attributes
  34         end
  35       end
  36
  37       def serializable_names
  38         serializable_attribute_names + serializable_method_names
  39       end
  40
  41       # Add associations specified via the <tt>:includes</tt> option.
  42       # Expects a block that takes as arguments:
  43       #   +association+ - name of the association
  44       #   +records+     - the association record(s) to be serialized
  45       #   +opts+        - options for the association records
  46       def add_includes(&block)
  47         if include_associations = options.delete(:include)
  48           base_only_or_except = { :except => options[:except],
  49                                   :only => options[:only] }
  50
  51           include_has_options = include_associations.is_a?(Hash)
  52           associations = include_has_options ? include_associations.keys : Array(include_associations)
  53
  54           for association in associations
  55             records = case @record.class.reflect_on_association(association).macro
  56             when :has_many, :has_and_belongs_to_many
  57               @record.send(association).to_a
  58             when :has_one, :belongs_to
  59               @record.send(association)
  60             end
  61
  62             unless records.nil?
  63               association_options = include_has_options ? include_associations[association] : base_only_or_except
  64               opts = options.merge(association_options)
  65               yield(association, records, opts)
  66             end
  67           end
  68
  69           options[:include] = include_associations
  70         end
  71       end
  72
  73       def serializable_record
  74         returning(serializable_record = {}) do
  75           serializable_names.each { |name| serializable_record[name] = @record.send(name) }
  76           add_includes do |association, records, opts|
  77             if records.is_a?(Enumerable)
  78               serializable_record[association] = records.collect { |r| self.class.new(r, opts).serializable_record }
  79             else
  80               serializable_record[association] = self.class.new(records, opts).serializable_record
  81             end
  82           end
  83         end
  84       end
  85
  86       def serialize
  87         # overwrite to implement
  88       end
  89
  90       def to_s(&block)
  91         serialize(&block)
  92       end
  93     end
  94   end
  95 end
  96
  97 require 'active_record/serializers/xml_serializer'
  98 require 'active_record/serializers/json_serializer'