Htykuut

I have a collection of 'data endpoints'. Each endpoint has a name and can be available or unavailable. In Ruby I want to present the available endpoints as a Hash to make it easy to work with them. The difficulty is that getting information about the endpoints is costly and should be done lazily.

Some examples of how I want my object to behave:

endpoints = get_endpoints.call        # No endpoint information is accessed yet

result = endpoints['name1']           # This should only query endpoint "name1"

is_available = endpoints.key? 'name2' # This should only query endpoint "name2"

all_available = endpoints.keys        # This has to query all endpoints

The comments describe how the object internally makes requests to the 'data endpoints'.

It is straightforward to make a Hash that can do the first 2 lines. However I don't know how to support the last 2 lines. To do this I need a way to make the keys lazy, not just the values.

Thank you for taking a look!

You'd have to override the key? method, and do your own checking in there.

class LazyHash < Hash

  def key?(key)

    # Do your checking here. However that looks for your application

  end

end

In my opinion, you're asking for trouble though. One of the most powerful virtues in computer science is expectability. If you're changing the behavior of something, modifying it far beyond it's intent, it doesn't serve you to continue calling it by the original name. You don't need to shoe-horn your solution into existing classes/interfaces.

Programming offers you plenty of flexibility, so you can do stuff like this (dependent on the language of course), but in that same argument, you have no reason not to simply build a new object/service with it's own API.

I recommend starting fresh with a new class and building out your desired interface and functionality.

class LazyEndpoints

  def on?(name)



  end



  def set(name, value)



  end

end

(Or something like that, the world is yours for the taking!)