LevelUp.Health.Fhir 0.1.0-preview.2

LevelUp.Health.Fhir

The FHIR R4 client skeleton for the LevelUp.Health backend (the asclepius P2 plane), lifted faithfully from ares-elite/aegis-api's Aegis.Infrastructure FHIR code. It ships the reusable HIPAA/FHIR plumbing — serializer, HTTP CRUD context, repository/service base classes, decorators, token services, DTOs — and turns every Ares-specific value into an option and every domain coupling into a port the consuming app fills.

Depends on LevelUp.Health.Abstractions for Result<T> / Error / Unit and the IContext / IRepository / IService / IDecorator contracts.

What's here

Consumption

// 1. Register the shared FHIR infrastructure (serializer, HTTP pipeline, no-op seam defaults).
builder.Services.AddFhirInfrastructure(builder.Configuration);

// 2. Register exactly the FHIR resource types you use (generic — no resource types ship in the package).
builder.Services.AddFhirResource<Patient>();
builder.Services.AddFhirResource<Observation>();

// 3. (optional) Layer caching + observability decorators over your registered IFhirService<T>s.
builder.Services.ConfigureDecoratorSettingsWithOverrides(builder.Configuration, builder.Environment.EnvironmentName);
builder.Services.AddDecoratedFhirServices();

FhirContextOptions binds from the FhirContextOptions configuration section (BaseAddress, ClientId, TenantId, Secret, DownstreamApiScopes).

Ports (fill these in the consuming app)

This package ships no-op defaults so it composes out of the box; replace a port when you need its real behavior.

• IIdentityPersonLinkResolver (default NoOpIdentityPersonLinkResolver, returns null). The caching decorator calls this on identity-resource writes to reverse-resolve a linking Person id and evict its identity:{personId} subgraph. The no-op makes the decorator fall back to the resource's own-id tag — safe, just less aggressive. Supply a real resolver if you model a Person-link identity graph. The Ares Person.link implementation is domain and does not ship.
• IFhirChangeTracker (default NoOpFhirChangeTracker, records nothing). FhirContext<T> invokes this on every write (create/update/delete). It is a FHIR-write concern kept self-contained here — it does not depend on the PHI-access audit package. Supply a real tracker to persist the change history.

Options (Ares values preserved as defaults)

The Ares-specific strings became options; the Ares value is the documented default:

Caching composition (paved-road P0, not re-extracted)

FhirServiceCachingDecorator<T> depends only on the Microsoft.Extensions.Caching.Hybrid.HybridCache abstraction. It does not reference FusionCache or any encrypting serializer — PHI-at-rest cache encryption is paved-road P0 (LevelUp.ServiceDefaults.Caching's EncryptingCacheSerializer + ICacheEncryptionKeyProvider, and LevelUp.ServiceDefaults.Azure's Key-Vault-backed rotating provider). The host (the levelup-health-app stamp, A4) wires those onto its HybridCache; this decorator then runs over the resulting cache. Tag-based eviction (HybridCache.RemoveByTagAsync) requires a tag-capable distributed L2 (Redis) — supplied at the host.

Equivalence & provenance

Behavior is byte-equivalent to Ares' shipped code (the serializer round-trips identically, the If-Match optimistic-concurrency path is identical). The Ares // <copyright> headers are stripped and namespaces rebranded Aegis.Infrastructure.* → LevelUp.Health.Fhir.* / Aegis.Core.* → LevelUp.Health.Abstractions.*. No Ares domain identifier survives except an option default.