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- LDPR: Linked Data Platform Resource
- LDPC: Linked Data Platform Container
To what extent can/should this class of objects be modeled as LDPRs not contained within a LDPC?
What are the benefits of such a model?
What are the drawbacks or limitations?
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Background: LDP and its mapping to Fedora objects
The LDP specification lays out the following concepts, interaction modes, and constraints on content:
| LDP Concept | LDP Interaction Modes | Constraints on Content |
|---|---|---|
| Container (LDPC) | LDPC, LDP-RS | RDF, must contain LDP membership triples for all members |
| Non-RDF Source (LDP-NR) | LDPR, LDP-NR | none |
| Non-Container RDF Source (LDP-RS-NC) | LDPR, LDP-RS | RDF |
The last concept "Non-Container RDF Source" isn't given a specific name in the LDP spec, so we call it an LDP-RS-NC for the sake of discussion.
The defining characteristics of the interaction modes described in LDP are briefly summarized as follows
- LDPC interaction mode defines ability to create resources within the container via HTTP POST, remove them via HTTP DELETE, and places requirements on the HTTP headers of the LDPC resource to advertise its role as a container.
- LDPR interaction mode does not imply the creation new resources with HTTP POST on an LDPR
- LDP-NR interaction mode implies POST, PUT, and PATCH do not have any special semantics; a resource is nothing more than a binary blob with a media type
- LDP-RS interaction mode implies that POST, PUT, GET, and PATCH are logical RDF operations with enhanced semantics and behaviour:
- LDP servers must interpret relative URIs as relative to the resource (for example, allowing null relative URIs "<>" to refer to the to-be-created resource URI)
- LDP Servers may adopt standards such as SPARQL/Update for update semantics via methods such as PATCH
- LDP Servers must provide, at minimum, text/turtle and application/ld+json representations when requested via GET.
At present, the mapping of Fedora concepts to LDP Concepts are as follows
| LDP Concept | Fedora Concept | LDP Interaction Modes | Constraints on Content |
|---|---|---|---|
| LDPC | Object | LDPC, LDP-RS | RDF, must contain LDP membership triples, subjects must be repository objects, subjects must be the URI of the object |
| LDP-NR | Datasteam | LDPR, LDP-NR | none |
| LDP-RS-NC | - | - | - |
The issue at hand is whether Fedora should support the LDP construct of an RDF source that is not also a container (LDP-RS-NC), and how such an resource in LDP would map to a concept in Fedora.
Proposal: Fedora container object with a child resource at a specified path redirecting to external content
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