ruby - How to create a Mongoid "within date range or nil" query? -

i'm trying create mongoid query records match date range, or have nil values. here ruby code performs function turn mongoid query:

class mymodel   include mongoid::document   field :name   field :enabled, type: boolean, default: false   field :start_date, type: datetime   field :end_date, type: datetime    def self.active     documents = where(enabled: true)     documents = documents.keep_if {|doc| doc.start_date.nil? || doc.start_date <= date.today}     documents = documents.keep_if {|doc| doc.end_date.nil? || doc.end_date >= date.tomorrow}     documents   end end 

how can improve performance turning method mongoid query?

update:

here rspec test i'm using verify correct behavior:

describe '.active'   let!(:disabled){ fabricate(:model, enabled: false, name: 'disabled') }   let!(:enabled_without_date){ fabricate(:active_model, name: 'enabled_without_date') }   let!(:past){ fabricate(:active_model, start_date: 1.week.ago, end_date: date.yesterday, name: 'past') }   let!(:current){ fabricate(:active_model, start_date: date.today, end_date: date.tomorrow, name: 'current') }   let!(:future){ fabricate(:active_model, start_date: date.tomorrow, end_date: 1.week.from_now, name: 'future') }    'returns enabled , within current time'     mymodel.count.should == 5     models = mymodel.active.to_a     models.should_not be_empty     models.should_not include disabled     models.should_not include past     models.should_not include future     models.should include enabled_without_date     models.should include current   end end 

maybe trick:

where(   enabled: true,   {:$or => [{start_date: nil}, {:start_date.lte => date.today.to_time   }]},   {:$or => [{end_date:   nil}, {:end_date.gte   => date.tomorrow.to_time}]} )