How to get created_at timestamp from mongo BSON id using mongoid

Writing this down as I always forget this, and this search query is not very google friendly either (and I usually waste a lot of time looking for this, and probably so would others). This is how you do it:

sample_object.id.generation_time

Now the bonus stuff! If you wan to do range queries for created_at timestamp on the BSON id, this is how you do it:

https://gist.github.com/amitsaxena/6977506
Rails 3ruby on railsrubymongodbmongoidtimestampcreated_atbson idgeneration_time