This is not at all how this is done. Your solution will load the entire set of IDs from the database, when it is only interested in two: The current ID, and the ID after or before it. What if there are 10,000,000 records? You'll create an array of 10 million integers, when all you need are two. You should absolutely not implement this as a select id from [table] order by [whatever] and process the entire table in Ruby, when a simple select * from [table] where id > [current] order by [whatever] limit 1 does the same job and returns a single record.

Note that, if I make all the changes you're suggesting (correcting several typos) to the OP's code, their code still does the exact same thing (calls st(st *source)) and ignores all of your additions. If you have a specific fix here, I think you need to provide additional compilable code that demonstrates how your suggestion applies to OP.

Why do they need to provide a copy constructor when the intent is to pass a const reference? There should be no copying here.

That's not really what CORS does. Anybody can connect to the server, with or without CORS, from any system they control. The point of CORS is to restrict how people can instruct your browser to connect to a service from a (hostile) website they control, and if/how they can review how the service responds.

@Stefan Love to see a monkeypatch needlessly polluting Hash with a method whose name is longer than its entire implementation.