Question

I’m using Rufus scheduler in a Sinatra app.
Can I access helper methods from within “scheduler do” block? I didn’t manage to do it (I get an “undefined method `check’ for main:Object” error) so now I have to define the method inside helpers block (to use it in “post ‘/’ do” block also) and then copy the method’s body to scheduler block. It does not make sense:( Is there a way to avoid repetition? Can I define a method somewhere else and call it in scheduler?

Answer 1

It depends where your scheduler is being used. A block will have access to the context local to it, so if you’re using it somewhere you have access to a helper, then it should also have access to the helper.

Taken in part from the docs

class MyApp < Sinatra::Base
  # Hey, I'm in the application scope!

  helpers do
    def my_helper
    end
  end

  configure do
    scheduler.every('20s') do
      # my_helper is ***not*** accessible here
    end
  end

  get '/define_route/:name' do
    # Request scope for '/define_route/:name'
    scheduler.every('20s') do
      my_helper
      # my_helper is accessible here
    end
  end
end

Having said that, you wouldn’t have access to the scheduler like that, so:

configure do
  set :scheduler, { Rufus::Scheduler.start_new }
end

and then you can do

  get '/define_route/:name' do
    # Request scope for '/define_route/:name'
    settings.scheduler.every('20s') do
      my_helper
      # my_helper is accessible here
    end
  end

or you could put it in a module’s class instance variable:

module MyScheduler
  def self.scheduler
    @scheduler ||= Rufus::Scheduler.start_new
  end
end

then you can access the scheduler everywhere via:

MyScheduler.scheduler

but the my_helper would still only be accessible in the request scope. If you wanted to access a method as a helper and outside the request scope, then extract it as jmettraux implied to:

module MyHelpers
  def self.my_helper
    # do something
  end
end

in Sinatra:

helpers
  def my_helper
    MyHelpers.my_helper
  end
end

then can do:

configure do
  scheduler = Rufus::Scheduler.start_new
  set :scheduler, scheduler
  scheduler.every('20s') do
    MyHelpers.my_helper
    # my_helper is not accessible here
    # but the MyHelpers.my_helper is, because it's accessible everywhere
  end
end

# and/or

get "another-route" do
  setting.scheduler.every('20s') do
    my_helper
    # my_helper is accessible here
  end
end

All very convoluted! You can mix and match and find what works for your needs.