List dynamic attributes in a Mongoid Model

Question

I have gone over the documentation, and I can\'t find a specific way to go about this. I have already added some dynamic attributes to a model, and I would like to be able to it

Answer 1

this will give you only the dynamic field names for a given record x:

dynamic_attribute_names = x.attributes.keys - x.fields.keys

if you use additional Mongoid features, you need to subtract the fields associated with those features: e.g. for Mongoid::Versioning :

dynamic_attribute_names = (x.attributes.keys - x.fields.keys) - ['versions']

To get the key/value pairs for only the dynamic attributes:

make sure to clone the result of attributes(), otherwise you modify x !!

attr_hash = x.attributes.clone  #### make sure to clone this, otherwise you modify x !!
dyn_attr_hash = attr_hash.delete_if{|k,v| ! dynamic_attribute_names.include?(k)}

or in one line:

x.attributes.clone.delete_if{|k,v| ! dynamic_attribute_names.include?(k)}