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

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