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- Metadata from extractors is not affected - this metadata is entered, stored, and displayed as before, with the exception exceptions that 1) it is pulled into a separate section (name configurable - Managed Metadata) by default) from the semantic metadata entered by users through the GUI or API, and 2) it starts collapsed rather than expanded. As in the original design, extractor metadata can have a context document, but the metadata itself is treated as json (the json-ld verification performed only checks that part of the message is json-ld but stores any plain json as well). The context provided is not used for display or interpreting the metadata.
- For semantic/json-ld metadata entered via the GUI or through a semantic extension of the metadata api, the primary artifact is a json doc of the current metadata values referencing a space json-ld context. Each 'metadata summary' doc refers to the dataset/folder/file it describes by ResourceReference (type + id). CRUD operations from the GUI or API update this document via the metadata service. A history section of this summary document captures updates (documenting not only new adds, but edits, deletes as well) - it could be managed as a separate document at some point.
- Context/definitions are maintained, one per space, as part of a doc containing all current terms (each term has label/URI and definition, type, and a flag indicating whether it is available in the add metadata menu. Additional info about any cardinality, recommended/required info, etc. could be added)
- The metadata api is extended to allow a 'content' entry which works as before (e.g. as used by extractors through pyclowder) or a content_ld entry which must provide a valid json-ld context for all submitted terms. Terms that match existing entries in the space's definitions are recorded using the labels from the definitions, regardless of what label is used in the api. Terms not in the space definitions are added to the space but flagged to not show up as new options in the 'add metadata' part of the GUI. This allows any terms to be entered while still allowing space admins to control what can be added via the GUI.
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