Distribution Health

Derives a distribution’s usability from two separately-produced signals:

• reachability – can the distribution be fetched? (HTTP/SPARQL level, produced continuously by the crawler’s probe)
• validity – does the fetched content actually parse as RDF? (a by-product of parsing: shallow by the crawler, deep by the knowledge-graph pipeline)

This is a pure leaf: it interprets the raw results of @lde/distribution-probe and @lde/sparql-importer rather than producing them. It contains no I/O and returns plain TypeScript – converting a verdict to RDF is the consumer’s job (see below), so the package stays vocabulary-agnostic.

What it provides

• A ValidityVerdict type with a typed failure reason (parse-error / empty), a best-effort parser message, the validatedFingerprint it was judged against, and its producer depth (shallow / deep).
• Mappers from a probe result (shallow) and an import outcome (deep) to a verdict.
• The usability rollup: (reachability, validity verdicts) → { usable | unusable | unknown, cause }, the one canonical rule consumers share. Reachability dominates; a stale verdict (one whose fingerprint no longer matches the currently-observed one) decays to unknown; a deep verdict beats a shallow one.

RDF is the consumer’s responsibility

This package emits no RDF and coins no vocabulary, mirroring @lde/iiif-validator (which returns a TS verdict that the NDE knowledge-graph pipeline maps to RDF). A consumer turns a ValidityVerdict into its own DQV/PROV quads under its own namespace – e.g. NDE writes a dqv:QualityMeasurement on the distribution under def.nde.nl. The ValidityFailureReason local names are chosen to drop straight into a SKOS failure scheme (<scheme>#${reason}) with no lookup table.

The normative usability rule and the rejected alternatives are recorded in the PRD: netwerk-digitaal-erfgoed/dataset-register#2103.