The existing functionality allows a resource to be retrieved by URL, and only a single-level depth traversal of the graph or relationships.
The Linked Data API (https://github.com/UKGovLD/linked-data-api) is an example of a configurable API that allows both parameterised queries and limited response graph construction.
This module would support several use cases typical of existing data publishing practices, that could be enhanced by Linked Data approach:
1) where the data is complex and partially populated, and in reality the client cannot predict what queries will deliver useful results
2) any client wishing to explore linked data and get a relevant graph of information in a single query
3) any publisher wishing to protect their system from uncontrolled SPARQL queries
4) any time the publisher wants to control the response graph for a given object
There are similarities with LDcache - in that such APIs can also be used to federate API access across multiple SPARQL endpoints. It is suggested therefore that this is a layer between the existing content-negotiation and ResourceWebService in the core.
A separate module may be beneficial - to encourage candidate providers to offer a solution in this space. adding to SPARQL perhaps less ideal because the user may not wish to expose SPARQL endpoints - but perhaps this can be handled by easy permissions configuration.