Question

I am suddenly completely lost with scope of variables in Rails with Mongoid. (Probably due to a lack of coffee).

All I want, is a way to set certain fields from within the application, but the only way I can find to do this, is by calling write_attribute.

class Example
  include Mongoid::Document
  field :foo

  def bar
    @foo = "meh"
  end
  def hmpf
    foo = "blah"
  end
  def baz
    write_attribute(:foo, "meh")
  end
end

e.bar   #=> "meh"
e.foo   #=> nil
e.hmpf   #=> "blah"
e.foo   #=> nil
e.baz   #=> [nil, "meh"]
e.foo   #=> "meh"

Am I using the scope wrong? Why will running foo = "bar" not set the field from within, it works from outside: e.foo = "blah" works trough the magic methods.

Answer 1

Try adding self to your attribute references when working in your model’s instance methods:

def hmpf
  self.foo = "blah"
end

Should do the trick.