openehr-its

openEHR ITS (Implementation Technology Specifications) for Rust: the canonical JSON and canonical XML serialization of the openEHR RM, the generated ITS-REST 1.1.0 API contract, OPT 1.4 template reading, and the Simplified Data Formats (FLAT / STRUCTURED / Web Template).

What it provides

• Canonical JSON — json::{to_canonical_json, from_canonical_json, from_canonical_value}: _type-first, BMM field order, a STRICT reader (undeclared/duplicate keys refused), refusal paths naming the offending JSON node, and validation against the embedded official ITS-JSON RM schema.
• Canonical XML — generated ToXml/FromXml implementations over a quick-xml runtime, serving both published XSD lineages (the root namespace is a serialize-time choice).
• ITS-REST contract — generated DTOs, #[async_trait] server traits, and route tables for every ITS-REST 1.1.0 API group, ready to implement over axum.
• Simplified Data Formats — the hand-written flat module: Web Template building, FLAT and STRUCTURED composition reading/writing.
• OPT 1.4 (opt14) and both AOM2 archetype XML codecs.
• default-features = false leaves a dependency-free island: rest::smart_scopes, the SMART on openEHR scope grammar — parseable from wasm32-unknown-unknown clients.

Generated code — do not edit

Every type file carries a // @generated header. The crate is emitted deterministically by openehr-codegen from the vendored openEHR BMM meta-model; hand-written spec behaviour (invariants, spec functions) lives in sibling *_impl.rs files the generator never rewrites. Changes belong in the emitter, never in the generated output.

Versioning

The package version is the crate's own independent SemVer line — it tracks this implementation's code and moves freely with fixes and improvements, never with the vendored openEHR specification (ITS-REST 1.1.0 (with ITS-XML and ITS-JSON alongside)). The implemented spec version is always available at runtime as openehr_its::SPEC_VERSION ("1.1.0"), independent of the package version.

Minimum supported Rust version

Rust 1.96 (edition 2024).

License

Licensed as MIT AND Apache-2.0:

• The Rust code and hand-written parts are MIT (LICENSE-MIT).
• The package embeds material derived from the official openEHR machine-readable specification artifacts, which openEHR publishes under Apache-2.0 (LICENSE-APACHE-2.0) — the generated codecs/contract derive from the vendored ITS XSD/OpenAPI/BMM artifacts, and the package embeds the official ITS-JSON RM schema (schemas/json/).

Part of FerroEHR

This crate is the serialization and REST-contract layer of FerroEHR, a pure-Rust, openEHR-spec-conformant Clinical Data Repository (ITS-REST 1.1.0 + AQL 1.1 on PostgreSQL 18). The crates are usable standalone; FerroEHR is the reference consumer.