MapperSelectors extension adds
Controller#set_selectors, which sets selectors in the controller’s
identity_map that ensure the fields returned from
Controller#expanded_fields (from the
FieldExpansion extension) are loaded for a given model when
identity_map.load(model) is called.
This will allow the mapper to save DB work and bandwidth by
selecting only the required database columns, and
tracking only the relevant associations, necessary to satisfy the output fields of the request.
To use this extension, include it in a controller with
include Praxis::Extensions::MapperSelectors. and define
before callbacks on relevant actions that call
set_selectors. For example: