Patch

Updating a part of your resource

In most Operations in FHIR, you manipulate a resource as a whole (create, update, delete operations). But sometimes you want to update specific data elements in a resource and do not care about the rest. In other words, you need an element/attribute level operation.

With the patch operation, you can update a part of a resource by sending a declarative description of operations that should be performed on an existing resource. To describe these operations in Aidbox, you can use different notations (methods):

• Merge Patch — simple merge semantics (read more in RFC);

• JSON Patch — advanced JSON transformation (read more in RFC);

• FHIRpath Patch - JSON patch with FHIRpath (since version 2503).

Patch Method

You can specify a patch method by the content-type header or by the _method parameter.

method	parameter	header
json-patch	json-patch	application/json-patch+json
merge-patch	merge-patch	application/merge-patch+json
fhirpath-patch	fhirpath-patch	-

If the method is not specified, Aidbox will try to guess it by the following algorithm:

• if the body contains "Parameters" resourceType, it is fhirpath-patch

• if the payload is an array, it is json-patch

• else merge-patch

Binary JSON-patch

Since version 2503, It is also possible to encode JSON patches using base64 Binary.data:

PATCH /fhir/Patient/1?_method=json-patch
content-type: application/json
accept: application/json

{
  "resourceType": "Binary",
  "contentType": "application/json-patch+json",
  "data": "WyB7ICJvcCI6InJlcGxhY2UiLCAicGF0aCI6Ii9hY3RpdmUiLCAidmFsdWUiOmZhbHNlIH0gXQ=="
}

Examples

Let's suppose we've created a Patient resource with the id pt-1

POST /Patient

resourceType: Patient
id: pt-1
active: true
name:
  - given: ['John']
    family: Doe
    use: official
  - given: ['Johny']
    family: Doe
telecom:
  -  system: phone
     value: '[phone]'
     use: work
     rank: 1
birthDate: '1979-01-01'

Merge Patch

Let's say we want to switch to an active flag to false and remove telecom:

PATCH /Patient/pt-1

active: false
telecom: null

# 200

id: pt-1
resourceType: Patient
name:
- use: official
  given:
  - John
  family: Doe
- given:
  - Johny
  family: Doe
active: false
birthDate: '1979-01-01'

JSON Patch

With JSON patch, we can do more sophisticated transformations — change the first given name, delete the second name, and change the active attribute value to true:

PATCH /Patient/pt-1

- op: replace
  path: '/name/0/given/0'
  value: Nikolai
- op: remove
  path: '/name/1'
- op: replace
  path: '/active'
  value: true

Response:

# 200 OK
id: pt-1
resourceType: Patient
name:
- use: official
  given:
  - Nikolai
  family: Doe
active: true
birthDate: '1979-01-01'

FHIRpath Patch

The example sets activeto false:

PATCH /fhir/Patient/pt-1

{
  "resourceType": "Parameters",
  "parameter": [
    {
      "name": "operation",
      "part": [
        {
          "name": "type",
          "valueCode": "add"
        },
        {
          "name": "path",
          "valueString": "Patient"
        },
        {
          "name": "name",
          "valueString": "active"
        },
        {
          "name": "value",
          "valueBoolean": false
        }
      ]
    }
  ]
}