Add support for nested queries
The REST API allows users to query through query_string. However, it does not support
nested objects, there is a related issue in invenio-search. Since the mappings are known before hand a custom filter can be set up in
invenio-records-rest. This is done in asclepias-broker: filter config.
For now all composed objects will be treated as
object, using the
include_in_parent = true propertie of the element. However, this property might be deprecated in the future.