[Monkey-Patch] Allow your rails4 to have a column as array of hash

rails_array_hstore.rb

module ActiveRecord
  module ConnectionAdapters
    class PostgreSQLAdapter < AbstractAdapter
      module Quoting
        def type_cast(value, column, array_member = false)
          return super(value, column) unless column

          case value
            when Range
              return super(value, column) unless /range$/ =~ column.sql_type
              PostgreSQLColumn.range_to_string(value)
            when NilClass
              if column.array && array_member
                'NULL'
              elsif column.array
                value
              else
                super(value, column)
              end
            when Array
              case column.sql_type
                when 'point' then PostgreSQLColumn.point_to_string(value)
                when 'json' then PostgreSQLColumn.json_to_string(value)
                else
                  return super(value, column) unless column.array
                  PostgreSQLColumn.array_to_string(value, column, self)
              end
            when String
              return super(value, column) unless 'bytea' == column.sql_type
              { :value => value, :format => 1 }
            when Hash
              case column.sql_type
                #aquajach: Add array_member
                when 'hstore' then PostgreSQLColumn.hstore_to_string(value, array_member)
                when 'json' then PostgreSQLColumn.json_to_string(value)
                else super(value, column)
              end
            when IPAddr
              return super(value, column) unless ['inet','cidr'].include? column.sql_type
              PostgreSQLColumn.cidr_to_string(value)
            else
              super(value, column)
          end
        end
      end
    end

    class PostgreSQLColumn < Column
      module Cast
        #aquajach: Add array_member as an option parameter
        def hstore_to_string(object, array_member = false)
          if Hash === object
            object.map { |k,v|
              "#{escape_hstore(k)}=>#{escape_hstore(v)}"
            #aquajach: escape hstore when array_member exists
            }.join(',').tap { |s| s.replace escape_hstore(s) if array_member }
          else
            object
          end
        end

        def string_to_hstore(string)
          if string.nil?
            nil
          elsif String === string
            #aquajach: replace Hash with HashWithIndifferentAccess
            HashWithIndifferentAccess[string.scan(HstorePair).map { |k,v|
              v = v.upcase == 'NULL' ? nil : v.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
              k = k.gsub(/\A"(.*)"\Z/m,'\1').gsub(/\\(.)/, '\1')
              [k,v]
            }]
          else
            string
          end
        end
      end
    end
  end
end