Consider REST API for adding/maintaining relations

[Pfeil]

Consider an API which makes it more convenient to add relations by providing a triple (a, rel, b), to create a relation rel from a to b.

Consider the following options:

• adding relation
• overriding (remove all and add) relations
• removing relation
• mutual (also add reverse relation if possible)

If profile is given, relation term may be human-readable instead of pid.

Implications:

• non-breaking change (minor version update)
• this will make scripts/tooling much easier and avoid errors on the clients side

Bonus thought: we could also request single attributes/relations, would this ease things in practice?

[Pfeil]

Alternative idea (both could be implemented, but they serve the same purpose):

Allow creating not only a single PID, but multiple ones which may refer to each other. Input would be an array of records.

References could look like one of these approaches:

• indexing into the input array like "my-pid-reference": "input[0]" or similar
• reference names: The pid records do have an optional PID field which is used for returning JSON and for the (optional, non-default, and not recommended) case where a suffix may be provided. We could use this suffix as a reference

[maximiliani]

In pull request #247, I implemented an endpoint which allows creating interconnected PID records. During this process, I was thinking what could be additional steps towards a “Relationship Management API”. Due to time constraints and a lack of current use case for this feature, I am posting some features I identified as possibly useful here:

• create POST /api/v1/pit/relationship endpoint for creating new relationships

  • add unidirectional relationships between two single FAIR-DOs with one key
  • add unidirectional relationships between one start and a list of target FAIR-DOs with one key
  • add multiple unidirectional relationships between one start and 1..n target FAIR-DOs with each one key
  • add bidirectional relationships between two single relationships and optionally different keys for each direction
  • add bidirectional relationships between one start and a list of target FAIR-DO with optionally different keys for each direction
  • add multiple bidirectional relationships between one start and 1..n target FAIR-DOs

• create PUT /api/v1/pit/relationship endpoint for overwriting relationships

  • bidirectionally remove all relationships to/from this FAIR-DO
  • unidirectionally remove all relationships from this FAIR-DO
  • redirect creation of new relationships to POST endpoint

• create PATCH /api/v1/pit/relationship endpoint for overwriting single relationships

  • remove all outgoing relationships for a specific key
  • remove all incoming relationships for a specific key
  • redirect creation of new relationships to POST endpoint

• create DELETE /api/v1/pit/relationship endpoint for removing relationships

  • unidirectional removal for single selected outgoing relationship
  • unidirectional removal for all outgoing relationships of a single FAIR-DO
  • unidirectional removal for single selected incoming relationship
  • unidirectional removal for all incoming relationships of a single FAIR-DO
  • bidirectional removal of multiple selected relationships for a single FAIR-DO (parameters: direction, key)
  • bidirectional removal of all relationships for a single FAIR-DO