Examples

The pack ships one shelf, fhir, which an instance lists under its examples once the pack is installed. Every document but fhir-fhirpath-plain-json talks to a local HAPI FHIR server, never a public one, because most of them write. Start one, and a second for the copy:

docker run -d --name fhir-source -p 8090:8080 hapiproject/hapi:v8.12.0-2
docker run -d --name fhir-target -p 8091:8080 hapiproject/hapi:v8.12.0-2

Document	What it does
fhir-read	Read one resource by its type and id.
fhir-search-paged	Search one type, following next links for at most five pages.
fhir-create-if-none-exist	Create a patient unless one with the same identifier is already there.
fhir-update-by-identifier	Write a patient over the one with the same identifier, or create it.
fhir-update-by-id	Write a patient at a known id, creating it there the first time.
fhir-patch	Change part of a patient with a JSON Patch and a FHIRPath Patch.
fhir-delete-test-data	Delete test patients by a search, bounded by max, and one by its id.
fhir-operation-everything	Invoke a patient's $everything, a $validate and a $expand.
fhir-copy-on-schedule	Copy patients and their observations from one server to another, nightly.
fhir-copy-page-by-page	Copy patients and observations to another server, a transaction per page.
fhir-fhirpath-high-readings	Find body weights over a limit, and the patients they belong to, with FHIRPath.
fhir-fhirpath-plain-json	Filter, map and reshape records that are not FHIR, with no server.
fhir-validate-before-copy	Validate a search's resources, and copy them only if they are sound.
fhir-measure-heavy-adults	Score heavy adults as a proportion of adults, with CQL, into a MeasureReport.

FHIR to FHIR on a schedule

fhir-copy-on-schedule is the pack's first flagship. One search reads every patient on the source with the observations that point at them (_revinclude=Observation:subject), and one transaction writes them to the target:

steps:
  find:
    block: fhir.search
    config:
      connection: fhir-source
      resource_type: Patient
      params:
        _revinclude: Observation:subject
        _count: "100"
      max_pages: 20

  copy:
    block: fhir.transaction
    depends_on: [find]
    config:
      connection: fhir-target
      bundle: ${steps.find.output.bundle}

The transaction rewrites each Observation.subject from the source's Patient/17 to the patient's urn:uuid, and writes every resource as a conditional update on its identifier. The source's ids never reach the target, and the second night writes over what the first created: created is zero and updated counts everything.

A page at a time

fhir-copy-page-by-page copies the same search with emit: pages, so the search hands on one Bundle per page and the copy fans out over them, one transaction per page:

steps:
  find:
    block: fhir.search
    config:
      connection: fhir-source
      resource_type: Patient
      params:
        _revinclude: Observation:subject
        _count: "50"
      max_pages: 100
      emit: pages

  copy:
    block: fhir.transaction
    depends_on: [find]
    for_each: ${steps.find.output.bundles}
    items: continue
    config:
      connection: fhir-target
      bundle: ${item}

Each page is its own item with its own status and retry, and one refused page fails its own item rather than the copy. emit: resources hands on one resource per item instead, for a step such as fhir.update that writes one at a time.

A complete project around the copy, with a verify.sh that starts two HAPI servers, seeds one, copies, and asserts the copy, is fhir-to-fhir in dirigent-examples.

FHIRPath on plain JSON

fhir-fhirpath-plain-json runs the three FHIRPath verbs over records that are not FHIR, written inline, with no connection and nothing else running:

dg run --local examples/fhir/fhir-fhirpath-plain-json.yaml -p limit=500000

filter.fhirpath keeps the cities over the limit, map.fhirpath builds a line from each and reads a hyphenated key in backticks, and transform.fhirpath walks into one object. The block reference says what to expect on data with no schema behind it.