Question

How could I DRY out the following piece of Rails code? The type parameter will correspond to Rails scopes, and I had assumed that all would work too … but it returns an array and my cunning plan fails.

The if looks wrong to me, but I can’t figure out how to have a all scope work correctly; any ideas?

Original code that improperly relied on all as a scope:

def readable(type=:all)
  StudyAid.send(type.to_s).authored_by(self)
end

Working but ugly version:

def readable(type=:all)
  if type == :all
    StudyAid.authored_by(self)
  else
    StudyAid.send(type.to_s).authored_by(self)
  end
end

Answer 1

I wouldn’t try and modify the behaviour of the all method because that could unexpectedly change the semantics of other parts of your code and would surprise other people who came to work with your code.

However you could define a named scope on StudyAid with a different name e.g.

named_scope :every

and then your method could become:

def readable(type=:every)
  StudyAid.send(type).authored_by(self)
end

Minor point: you can use symbols with send so your to_s call isn’t needed.

Finally, I don’t think your version is as ugly as you think yourself.