how do i check for the existence of a method in a rails application controller?

Question

Hi All,

In my application controller, I have a method that is supposed to check for the existence of another method in a subclassed controller to set the filename of a downloaded file, but i'm having trouble making it work properly

i've tried

def filename
  begin
    send "filename_method"
  rescue NoMethodError
    default_filename
  end
end

and

def filename
 if respond_to?("filename_method")
  send "filename_method"
 else
  default_filename
 end
end

but both always return default_filename, even if filename_method is defined in the subclassed controller. Can someone point me in the right direction here?

Thanks,

-C

Answer 1

I'm guessing this is due to the fact that the controller superclass does not know of the existence of the subclass's methods. You can confirm this by inspecting the methods array of the subclass.

It seems like the solution is to reconsider your design. Instead of checking for the existence of filename_method, just provide the default filename behavior in the base filename method and override the filename method in the subclass to provide custom filename functionality.

For example, in your superclass:

def filename
  # return default file name 
end

And in your subclass:

def filename
  # return custom file name 
end