Question

From time to time I have user.id == nil. And when this happens my lookup fails. What is the most practical way to rescue this code? and what do you typically return when this happens?

def lookup  
  @data[user.id]["email"]
end

Say a mail method is using the returned value

email(lookup).deliver

Answer 1

begin
  @data[user.id]["email"]
rescue Exception
  nil
end

or you might be able to do

@date[user.try(:id)]["email"]

which will just return nil if user is nil and you call id on it.

The real problem here is that you’ve got a code smell. Whatever class owns the lookup method knows too much about the implementation details of @data. I can’t recommend a fix without more code, but I’d suggest writing a method/class that only knows how to pull the email out of data. Something like:

@data.get_email_for_user

That way this class wouldn’t have to worry about whether or not user is nil. It only has to worry about returning the email.