Registry Query API¶
Query interface — instantiates Registry-Mediated Discovery
Exposes a programmatic contract for filtering the registry by attributes and returning locator records through access-scoped, privacy-filtered views, so callers discover by criteria rather than by knowing one exact key.
A Registry Query API is the programmatic front door to a registry for callers who know criteria but not one exact key. What makes it this mechanism is the flexible, machine-facing query contract layered over field-level access and privacy control: a caller submits a structured query — filter by type, capability, version, region — and the API returns the matching locator records, but only the records and fields that caller is entitled to see. It is not a single-name resolver and it is not a schema-defined store you bind to; it is an interface whose defining features are (a) expressive attribute queries and (b) a discipline for returning just enough — a privacy-preserving view that answers the caller's question without over-exposing the registry.
Example¶
A genomics platform lets client tools discover data resources through a programmatic registry API in the spirit of identifiers.org and the GA4GH service-info convention. A pipeline needs "all resources of type variant-store that support the current API version and hold data in a jurisdiction it is cleared for." It issues that query and gets back a list of matching endpoints — each entry stripped to what the pipeline may know: public resources return full locator records, restricted ones return only "exists, contact your data-access committee," and fields like internal owner or unpublished datasets are absent entirely. A different caller with broader clearance, running the same query, sees more. The API answered a criteria-shaped question and shaped its answer to the asker's entitlements — never resolving one known key, and never returning a raw dump.
How it works¶
Callers hit a documented query contract — a set of filterable attributes and a response shape — rather than a fixed lookup key. The API evaluates the filter against the registry and assembles a candidate result set, then passes it through two gates before returning it: an access check that decides which records the caller may see at all, and a projection that decides which fields of each visible record to include, redacting or coarsening the rest. This second gate is the privacy-preserving view — the same query yields different, correctly-scoped answers to different callers, so discovery never becomes a side channel for data the caller has no right to. Rate limits and query-shape restrictions bound how much can be extracted per request.
Tuning parameters¶
- Query expressiveness — how rich the filter language is. Expressive queries serve more use cases but widen the surface for expensive or extractive queries.
- Field projection policy — which attributes each caller class may see. Aggressive redaction protects sensitive metadata but can starve legitimate integrations.
- Access granularity — record-level versus field-level entitlement checks. Fine grain enforces least privilege precisely and multiplies policy to maintain.
- Rate and result limits — how much a caller can pull per query and per window. Tight limits blunt scraping and frustrate bulk consumers.
- Result determinism — whether the same query is stable across calls. Stable results ease client caching; volatile results reflect a fast-changing registry more truthfully.
When it helps, and when it misleads¶
It is the right mechanism when callers must discover by properties and the registry holds data of mixed sensitivity — some public, some restricted, some redacted. It combines expressive discovery with disciplined disclosure, so a single interface can serve public integrators and privileged internal tools without leaking across the line. Its failure mode is that flexible queries plus incomplete field control quietly become an exfiltration channel: a caller reconstructs restricted facts by combining many innocuous-looking queries, or infers a redacted field from which records the API declines to return. The guarding discipline is least privilege applied to discovery itself — return the minimum that answers the question — plus watching aggregate query patterns, not just single requests, for inference attacks.[n1]
How it implements the components¶
resolver_or_query_contract— its core: a documented, attribute-based query interface that returns matching locator records programmatically.visibility_and_access_policy— access checks decide which records a given caller is permitted to discover at all.privacy_preserving_discovery_view— field projection returns a caller-scoped view, redacting or coarsening what the asker may not see.
It does not bind a single stable_discovery_key or walk a registry_partition_or_namespace to resolve one name — that is Name Resolution Service — and it defines no locator_record_schema of its own, which is Directory Service's contribution; a query API filters and scopes existing records, it neither resolves one key nor owns the record shape.
Related¶
- Instantiates: Registry-Mediated Discovery — the criteria-based, privacy-scoped query front door to a registry.
- Sibling mechanisms: Name Resolution Service · Directory Service · Catalog or Broker Directory · Service Registry · Federated Registry Synchronization · Human Referral Directory · Lease or Heartbeat Registration · Resolver Cache with TTL · Successor Forwarding Record
Editorial Notes¶
Form Classification¶
Form family: Control, Automation & Runtime
Rationale: Registry Query API operates as a live operational control that automatically routes, enforces, adapts, or responds during execution because it exposes a programmatic contract for filtering the registry by attributes and returning locator records through access-scoped, privacy-filtered views, so callers discover by criteria rather than by knowing one exact key.
Independent corroboration: The frozen evidence defines Registry Query API as 'Exposes a programmatic contract for filtering the registry by attributes and returning locator records through access-scoped, privacy-filtered views, so callers discover by criteria rather than by knowing one exact key', so its operative form is Control, Automation & Runtime.
Nearest alternative: Decision, Gate & Allocation — Registry Query API includes features of a case-specific gate, selection, routing, prioritization, or resource disposition, but its defining operation is a live operational control that automatically routes, enforces, adapts, or responds during execution.
Review outcome: Independent reviewer agreement; medium confidence.
Origin Attribution¶
Primary origin: Computer Science & Software Engineering
Origin pattern: Cross-disciplinary synthesis
Present-day reach: Specialized
Rationale: Programmatic query contracts and privacy-filtered views are software and database architecture.
Related originating lineages:
- Library & Information Science — Registry indexing and attribute-based discovery materially define the information-retrieval function.
Review outcome: Independent reviewer agreement; high confidence.
Notes¶
[n1] The principle of least privilege — grant each requester only the access its task requires, nothing more. Applied to discovery, it means returning the minimum records and fields that answer the query, which is the primary defense against a flexible query interface becoming an inference or exfiltration channel. ↩