ferrobridge-validator

A FHIR R4 profile validator over FHIR packages read offline, the generated model and element table of fhir-types.

Part of FerroBRIDGE, a pure-Rust bridge between openEHR and two interoperability targets: HL7 FHIR through the FHIRconnect specification, and the OMOP Common Data Model through the OMOCL specification.

What it does

• Reads FHIR packages from .tgz files and unpacked directories (<dir>/package/package.json), refuses a set whose manifests name a dependency it does not hold, and resolves StructureDefinitions by canonical, url|version or url alone for the latest version. Every definition decodes into the generated fhir_types::r4 model.
• Validates a resource, held in the lexical fhir_types::codec::Value document model, against the core definition of its type or a profile the package set carries. The R4 element table gives the base structure; the profile's snapshot gives the constraints.
• Reports typed issues with a severity, an R4 issue type, the FHIRPath location (Patient.name[0].given[1]), a message id and a message, and converts the report into an R4 OperationOutcome.

The structural checks are unknown members, the JSON shapes (no empty object, array or string, aligned primitive arrays), cardinality per parent occurrence, the types a choice may take, contentReference, the lexical form of every primitive read from the regex extension of its own definition, the integer ranges, the length a primitive's definition allows and a profile's maxLength, fixed[x], pattern[x], and extensions resolved by url and walked against their definition.

Slicing is evaluated as FHIR R4 profiling defines it: the discriminator types value, exists, pattern, type and profile over paths in the simple FHIRPath subset (resolve() through contained resources, extension(url), ofType() and as()), a required binding over a value set the package set enumerates, slicing without a discriminator, the rules closed, open and openAtEnd, ordered slicing, the @default slice, re-slicing, extension slices by url, and the cardinality of each slice and of the slicing entry. An item matched to a slice is held to the slice's own constraints. Content is validated against the profiles its type names and passes when it conforms to one of them.

Invariants, terminology bindings, target profiles and the profiles a resource claims are not evaluated yet, and neither is a discriminator the validator cannot decide (a path outside the subset, a reference outside the resource, a value set it cannot enumerate). Each one the validator meets is listed in the report and in the OperationOutcome as a warning of type not-supported, never passed in silence.

Message ids

R4 defines no validator messages, so the ids are this crate's own vocabulary. An OperationOutcome issue carries its id as a details.coding in the system https://ferrobridge.eu/fhir/CodeSystem/validator-message, and its message in details.text.

Licence

Business Source License 1.1; see LICENSE.