A server managed triple (SMT for short) is any triple for a resource which is created and managed by the server, and may in some cases be used by the server for inspection and identification of said resources. As such, clients may not modify these properties directly via PUT/PATCH/POST requests. Instead, they are often generated as a side effect of other actions, such as creating a container or a binary, or adding a child resource.
Clients may request to omit server managed triples from RDF responses from the server using the "Prefer: return=representation; omit=http://fedora.info/definitions/v4/repository#ServerManaged" header as described in
the RESTful API documentation
When committing changes to the server via PUT, clients may provide all non-server managed triples for the resource by including the "handling=lenient; received="minimal" header as described in the RESTful API PUT documentation, which is based on https://tools.ietf.org/html/rfc7240#section-4.4
Server Managed Predicates
The following properties are considered to be server managed (see the list of namespace prefixes later in the document):
- ldp:contains
- premis:hasMessageDigest
- premis:hasFixity
- All predicates in the fedora namespace
- All predicates in the memento namespace
Additionally, clients may not specify a ldp:hasMemberRelation relationship on a Direct or Indirect Container with a server managed predicate as the object, as this would cause the inappropriate creation of server managed triples. Similarly, relationships generated by Direct/Indirect containers cannot be deleted by clients.
Server Managed Types
In addition to predicates, the following URIs are considered server managed when provided as the object of an rdf:type property:
- rdf:type fedora:* (any type in the fedora namespace)
- rdf:type memento:* (any type in the memento namespace)
- rdf:type ldp:* (any type in the ldp namespace)
Relaxable Properties
A subset of SMTs can be modified by clients, but only when the server is put into "relaxed" mode. This concept is described in more detail in the article How to allow user-updates to certain server managed triples. The following properties fall into this category:
- fedora:lastModified
- fedora:lastModifiedBy
- fedora:created
- fedora:createdBy
Server Generated Properties
Some properties are generated by the server, but not managed thereafter. As such, they may be directly overridden by the clients after creation, including:
- premis:hasSize
- ebucore:hasMimeType
- ebucore:filename
- iana:describedby
Namespaces Referenced in this Document
- fedora =>
http://fedora.info/definitions/v4/repository# - premis => http://www.loc.gov/premis/rdf/v1#
- ldp => http://www.w3.org/ns/ldp#
- rdf => http://www.w3.org/1999/02/22-rdf-syntax-ns#
- memento => http://mementoweb.org/ns#
- iana => http://www.iana.org/assignments/relation/
