There should be a way to write xrefs to API nodes rather than Site nodes

[Robbie1977]

We now have an API node (short_form:jrc_slide_code_api) for adding Janelia slide codes without exposing them as there is no 'Site' that links could work too. This works fine however curation fails when writing (not at testing!?) as the matching 'Site' node doesn't exist (as it's :api).

This isn't urgent as we can bypass but api nodes might become more common in future for adding non linking IDs/Meta.

Accepting either Site or api labels for matching xref links would resolve this.

[dosumis]

Addition of xrefs currently assumes site node: https://github.com/VirtualFlyBrain/VFB_neo4j/blob/master/src/uk/ac/ebi/vfb/neo4j/KB_tools.py#L357

Options:

• Extend this function with kwarg specifying :Site as default otype. Challenge - how to make this easy to spec in addition patterns - will this need yet another arg?
• Allow otype to be either API or Site. Can we do this in one write statement? Or do we need to try Site & if that fails try with API?

Challenge - how to make this ieasy

[Clare72]

is it possible to add a parent node type e.g. 'xref' node that would encompass anything we might want to use in an xref - 'Site' or 'API' or anything else we might want in future? then we could use that for the otype.

[dosumis]

There's no hierarchy in neo :labels. We need to be able to specify API vs Site in order to direct whether the xref will be used to generate a link on VFB (Site nodes only) or not.

[dosumis]

Probably easiest to add yet another arg here allowing api_xrefs:

https://github.com/VirtualFlyBrain/VFB_neo4j/blob/master/src/uk/ac/ebi/vfb/neo4j/KB_tools.py#L875

Supporting this by modifying the add_xref method with kwarg to support addition of xrefs to API nodes, with 'Site' as default to prevent this from breaking current usage.