Ruby/Rails, Gate clause syntax to enforce security policy - ruby-on-rails

Question

I have a difficult problem to solve.
I would like to replicate, the title_with_if_statement methods results, but using the syntax used in the title method. However, I do not know what to put in the enforce_policy_to_level() method to accomplish this.
I can do 'title_less_readable', but I find the title method much more readable since the policy is right at the top, and since I will be doing this for hundreds of methods, I want to keep it DRY and readable.
Any advice?
Is this even possible? It's basically a before_action but uses the method's own results.
class Car
def title
enforce_policy_to_level(1)
# Code that returns the "Car Title" string
"Car Title"
end
def title_less_readable
# Code that returns "Car Title" string
content = "Car Title"
return secure_text(content) unless authorized_to_level?(1)
content
end
def title_with_if_statement
# Code that returns the "Car Title" string
content = "Car Title"
if authorized_to_level?(1)
content
else
secure_text(content)
end
end
private
def enforce_policy_to_level(level)
# Return from title method with the secured result of title method
# if it's not authorized. In this example it would be secure_text('Car Title')
# which output return '---------'
# If if authorized, just continue with how title method would normally return
end
def authorized_to_level?(level)
current_user_level = 1 # Dynamic from user record
current_user_level >= level
end
def secure_text(text)
'X' * text.length
end
end

Answer 1

Why not just something like this?
def title
enforce_policy_to_level(1) do
"Car Title"
end
end
private
def enforce_policy_to_level(level, &block)
if authorized_to_level?(level)
secure_txt yield
else
yield
end
end

Answer 2

Consider separating your concerns: I'd approach this by creating a separate function that handles the authorization.
module AuthorizedText
module_function
def secure_text(text, authorized)
return authorized ? text : 'X' * text.length
end
end
Call this in Car like this:
AuthorizedText.secure_text("Car Title", authorized_to_level(1))
You can shorthand this with a convenience method:
def secure(level, text)
AuthorizedText.secure_text(text, authorized_to_level(level))
end
so that your car_title method would look like
def car_title
secure(1, "Car Title")
end
You could generalize a method wrapper by defining a class method that would let you do something like
def car_title
"Car Title"
end
secure :car_title
But I'd call this over-engineered and ultimately less readable to anyone who isn't you (including you 8 months from now, likely!). I'd avoid trying to be fancy like this, as fun as it may be.
Also, if current_user and current_user_level make sense outside the context of Car and you may want to reuse this elsewhere, you could go further by moving the auth checking methods into AuthorizedText, if that's appropriate:
module AuthorizedText
module_function
def secure_text(text, user, level = 0)
return authorized?(user, level) ? text : 'X' * text.length
end
def authorized?(user, level)
# for example; I don't know what your user object looks like
user.level >= level
end
end