Introduction

In a previous post, I wrote about the steps I followed to add Authentication (AuthN) to HAPI FHIR by utilising APISIX and Keycloak.

In this post we are going to look at adding support for SMART on FHIR to HAPI FHIR.

SMART on FHIR

SMART on FHIR (Substitutable Medical Applications and Reusable Technologies on FHIR) is a healthcare standard that promotes interoperability between client applications and FHIR-enabled systems.

SMART on FHIR Scopes

SMART on FHIR defines OAuth 2.0 scopes that allow client applications to request a specific set of access rights. The client conveys this information to the authorization server in the form of a 'scope' request parameter.

For example:

  • system/Patient.read
  • system/Patient.write

APISIX

OpenID Connect Plugin

We can configure the OpenID Connect plugin's required_scopes attribute to require one or more scopes.

For example:


  ...

  - name: hapi-fhir-api
    uri: /fhir/Patient*
    methods: [ "GET" ]    
    upstream_id: 1
    plugins:
      openid-connect:
        bearer_only: true
        client_id: ${{CLIENT_ID}}
        client_secret: ${{CLIENT_SECRET}}
        discovery: ${{PROTOCOL}}://${{KEYCLOAK_HOSTNAME}}:${{KEYCLOAK_PORT}}/realms/${{KEYCLOAK_REALM}}/.well-known/openid-configuration
        required_scopes: [ "system/Patient.read" ]

See: apisix-standalone.yml

APISIX will call the token introspection endpoint and check that the Access Token includes the required scopes.

Keycloak

Request a token

To access the HAPI FHIR API, you must first request an access token. You will need to POST to the token URL.

For example (scope=system/Patient.read):

ACCESS_TOKEN=$(curl -s -X POST https://keycloak.au.localhost:8443/realms/hapi-fhir-dev/protocol/openid-connect/token \
  -H 'content-type: application/x-www-form-urlencoded' \
  -d grant_type=client_credentials \
  -d client_id=oauth2-proxy \
  -d client_secret=aHkRec1BYkfaKgMg164JmvKu8u9iWNHM \
  -d scope=system/Patient.read | (jq -r '.access_token'))
                 
# echo "$ACCESS_TOKEN"

Note: You can use jwt.io to decode the access token.

Introspect a token

To introspect an Access Token you will need to POST to the introspect URL.

For example:

curl -X POST "https://keycloak.au.localhost:8443/realms/hapi-fhir-dev/protocol/openid-connect/token/introspect" \
  -H 'content-type: application/x-www-form-urlencoded' \
  -d client_id=oauth2-proxy \
  -d client_secret=aHkRec1BYkfaKgMg164JmvKu8u9iWNHM \
  -d "token_type_hint=access_token&token=$ACCESS_TOKEN"
Client Scopes

In Keycloak, an OAuth 2.0 scope is mapped to a client scope.

See: Keycloak - Client Scopes

HAPI FHIR

Call the API

To call the HAPI FHIR API, a client application must pass an access token as a Bearer token in the Authorization header of your HTTP request.

For example:

curl -X GET https://hapi-fhir.au.localhost/fhir/Patient?_id=baratz-toni \
  -H 'Content-Type: application/fhir+json' \
  -H "Authorization: Bearer $ACCESS_TOKEN"

You should see something like:

{
  "resourceType": "Bundle",
  "id": "9d80c83a-0b06-4b78-bce2-21e6666348d8",
  "meta": {
    "lastUpdated": "2025-05-23T05:43:01.959+00:00"
  },
  "type": "searchset",
  "total": 1,
  "link": [ {
    "relation": "self",
    "url": "https://hapi-fhir.au.localhost/fhir/Patient?_id=baratz-toni"
  } ],
  "entry": [ {
    "fullUrl": "https://hapi-fhir.au.localhost/fhir/Patient/baratz-toni",
    "resource": {
      "resourceType": "Patient",
      "id": "baratz-toni",
      "meta": {
        "versionId": "1",
        "lastUpdated": "2025-05-23T05:42:36.551+00:00",
        "source": "#rKTCeZfmnReSjm8X",
        "profile": [ "http://hl7.org.au/fhir/core/StructureDefinition/au-core-patient" ]
      },
      "extension": [ {
        "url": "http://hl7.org.au/fhir/StructureDefinition/indigenous-status",
        "valueCoding": {
          "system": "https://healthterminologies.gov.au/fhir/CodeSystem/australian-indigenous-status-1",
          "code": "1",
          "display": "Aboriginal but not Torres Strait Islander origin"
        }
      }, {
        "url": "http://hl7.org/fhir/StructureDefinition/individual-genderIdentity",
        "extension": [ {
          "url": "value",
          "valueCodeableConcept": {
            "coding": [ {
              "system": "http://snomed.info/sct",
              "code": "446141000124107",
              "display": "Identifies as female gender"
            } ]
          }
        } ]
      }, {
        "url": "http://hl7.org/fhir/StructureDefinition/individual-pronouns",
        "extension": [ {
          "url": "value",
          "valueCodeableConcept": {
            "coding": [ {
              "system": "http://loinc.org",
              "code": "LA29519-8",
              "display": "she/her/her/hers/herself"
            } ]
          }
        } ]
      }, {
        "url": "http://hl7.org/fhir/StructureDefinition/individual-recordedSexOrGender",
        "extension": [ {
          "url": "type",
          "valueCodeableConcept": {
            "coding": [ {
              "system": "http://snomed.info/sct",
              "code": "1515311000168102",
              "display": "Biological sex at birth"
            } ]
          }
        }, {
          "url": "value",
          "valueCodeableConcept": {
            "coding": [ {
              "system": "http://snomed.info/sct",
              "code": "248152002",
              "display": "Female"
            } ]
          }
        } ]
      } ],
      "identifier": [ {
        "extension": [ {
          "url": "http://hl7.org.au/fhir/StructureDefinition/ihi-status",
          "valueCoding": {
            "system": "https://healthterminologies.gov.au/fhir/CodeSystem/ihi-status-1",
            "code": "active"
          }
        }, {
          "url": "http://hl7.org.au/fhir/StructureDefinition/ihi-record-status",
          "valueCoding": {
            "system": "https://healthterminologies.gov.au/fhir/CodeSystem/ihi-record-status-1",
            "code": "verified",
            "display": "verified"
          }
        } ],
        "type": {
          "coding": [ {
            "system": "http://terminology.hl7.org/CodeSystem/v2-0203",
            "code": "NI"
          } ],
          "text": "IHI"
        },
        "system": "http://ns.electronichealth.net.au/id/hi/ihi/1.0",
        "value": "8003608000311662"
      }, {
        "type": {
          "coding": [ {
            "system": "http://terminology.hl7.org/CodeSystem/v2-0203",
            "code": "MC"
          } ],
          "text": "Medicare Number"
        },
        "system": "http://ns.electronichealth.net.au/id/medicare-number",
        "value": "69518252411"
      } ],
      "name": [ {
        "use": "official",
        "family": "BARATZ",
        "given": [ "Toni" ]
      } ],
      "telecom": [ {
        "system": "phone",
        "value": "0870101270",
        "use": "home"
      }, {
        "system": "phone",
        "value": "0491570156",
        "use": "mobile"
      }, {
        "system": "phone",
        "value": "0870108006",
        "use": "work"
      } ],
      "gender": "female",
      "birthDate": "1978-06-16",
      "address": [ {
        "line": [ "24 Law Cir" ],
        "city": "Bassendean",
        "state": "WA",
        "postalCode": "6054",
        "country": "AU"
      } ]
    },
    "search": {
      "mode": "match"
    }
  } ]
}
Source Code

What's Next

In the next post, we'll take a look at APISIX's authz-keycloak plugin.

References
System Hardening
HL7
SMART on FHIR
SMART on FHIR - Standalone Launch
SMART on FHIR - EHR Launch
Keycloak
Keycloak-based Development
Keycloak Support
APISIX
HAPI FHIR