According to the mongo docs, my return object should contain a lastErrorObject, which should indicate if the object is new or old, through updatexisting. I do not see this object. How can I fix my query in order to distinguish between new objects created and found objects?
db['posts'].find_and_modify({:query=>{"id"=>post_hash["id"]}, :update=>post_hash, :upsert=>true})
What have I done wrong?
The documentation to which you refer is not specific to the ruby driver. Try adding the :full_response=>true option as documented here:
http://api.mongodb.org/ruby/current/Mongo/Collection.html#find_and_modify-instance_method
It should return a hash with the requested document ("value") and a "lastErrorObject" hash with a field "updatedExisting" that you can check. Hope that helps.