Returning true or error message in Ruby

Question

I\'m wondering if writing functions like this is considered good or bad form.

def test(x)
    if x == 1
        return true
    else
        return \"Error:          


        

Answer 1

I would say that methods that return different types (e.g. boolean vs. string vs. numbers) under different circumstances are a bad practice.

If you have some sort of test method that wants to return details of why the test has not passed then you can return a pair of values (an Array) as follows:

def test(x)
    if x == 1
        return true, "x is fine"
    else
        return false, "Error: x is not equal to one."
    end
end

and then write the section of your controller code as:

valid, message = @item.save_image(params[:attachment][:file])

if !valid
  flash[:notice] = message
  redirect_to(new_item_url) and return
end

If you're talking about a save_image method that will succeed the majority of the time but may fail and you want to indicate this failure and the reason then I would use exceptions e.g.

def save_image(file)
  raise "No file was specified for saving" if file.nil? 
  # carry on trying to save image
end

and then your controller code would be along the lines of:

begin
  result = @item.save_image(params[:attachment][:file])
rescue Exception => ex
  flash[:notice] = ex.message
  redirect_to(new_item_url) and return
end