Module: ArVirtualField

Defined in:
lib/ar_virtual_field.rb,
lib/ar_virtual_field/version.rb

Defined Under Namespace

Modules: HelperMethods Classes: FieldsData

Constant Summary collapse

VERSION =
"1.0.5"

Instance Method Summary collapse

Instance Method Details

#virtual_field(name, scope: nil, select:, get:, default: nil) ⇒ Object



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# File 'lib/ar_virtual_field.rb', line 52

def virtual_field(name, scope: nil, select:, get:, default: nil)
  @ar_virtual_fields ||= FieldsData.new

  name = name.to_s
  current_class = self

  if default
    default = HelperMethods.wrap_to_lambda(default)
  end

  select = HelperMethods.wrap_to_lambda(select)

  if scope
    field_name = Arel.sql(HelperMethods.table_with_column(name))

    select_lambda =
      if default
        -> { Arel::Nodes::NamedFunction.new('COALESCE', [field_name, default.()]) }
      else
        -> { field_name }
      end

    scope_name = :"_scope_#{name}"

    scope(scope_name, scope)

    scope(:"with_#{name}", -> do
      scope_query = current_class
        .send(scope_name)
        .select(select.().as(name), "#{table_name}.id")

      HelperMethods.select_append(joins("        LEFT JOIN (\#{scope_query.to_sql}) \#{HelperMethods.table_name(name)}\n          ON \#{\n            Array(primary_key).map do |pk|\n              \"\#{HelperMethods.table_name(name)}.\#{pk} = \#{table_name}.\#{pk}\"\n            end.join(' AND')\n          }\n      SQL\n    end)\n  else\n    select_lambda =\n      if default\n        -> { Arel::Nodes::NamedFunction.new('COALESCE', [select.(), default.()]) }\n      else\n        select\n      end\n\n    scope(:\"with_\#{name}\", -> do\n      HelperMethods.select_append(self, select_lambda.().as(name))\n    end)\n  end\n\n  @ar_virtual_fields[name.to_sym] = select_lambda\n\n  method_name = :\"ar_virtual_field_\#{name}\"\n\n  define_method(method_name, &get)\n  define_method(name) do\n    if ActiveRecord::Base.connection.query_cache_enabled\n      attributes.key?(name) ? self[name] : send(method_name)\n    else\n      send(method_name)\n    end\n  end\nend\n".squish), select_lambda.().as(name))

#virtual_fieldsObject



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# File 'lib/ar_virtual_field.rb', line 48

def virtual_fields
  @ar_virtual_fields || FieldsData.new
end