Module: Plucker::ClassMethods

Defined in:
lib/plucker.rb

Overview

:nodoc:

Instance Method Summary collapse

Instance Method Details

#plucker(*args, &block) ⇒ Object

Plucker allows projecting records extracted from a query into an array of specifically defined Ruby structs for the occasion. It is an enchanted ‘pluck`. It takes a list of values you want to extract and throws them into a custom array of Ruby struct.



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# File 'lib/plucker.rb', line 19

def plucker(*args, &block)
  scope = current_scope || self.all
  scope_table_name = scope.table.name
  columns = []
  alias_names = []
  args.each do |value|
    case value
    when Symbol
      if value == :*
        scope_table_name.classify.constantize.columns.map do |column|
          columns << column.name
          alias_names << column.name.to_sym
        end
      else
        columns << value.to_s
        alias_names << value
      end
    when String
      table_name, column_name = value.split('.')
      if column_name == '*'
        table_name.classify.constantize.columns.map do |column|
          columns << column.name
          alias_names << "#{table_name}_#{column.name}".parameterize(separator: '_').to_sym
        end
      else
        columns << Arel.sql(value)
        alias_names << value.parameterize(separator: '_').to_sym
      end
    when Hash
      value.map do |k, v|
        columns << Arel.sql(v.to_s)
        alias_names << k.to_sym
      end
    else
      raise "Invalid plucker argument: '#{value.inspect}'"
    end
  end

  struct = Struct.new(*alias_names) do
    class_eval(&block) if block
  end
  scope.pluck(*columns).map do |record|
    struct.new(*record)
  end
end