Add FHIRPath Patch support

[FlixCoder]

Hi!

I am making a PATCH request to a Patient with the following body:

{
  "resourceType": "Parameters",
  "parameter": [
    {
      "name": "operation",
      "part": [
        {
          "name": "type",
          "valueCode": "add"
        },
        {
          "name": "path",
          "valueString": "Patient"
        },
        {
          "name": "name",
          "valueString": "birthDate"
        },
        {
          "name": "value",
          "valueDate": "2021-02-01"
        }
      ]
    },
    {
      "name": "operation",
      "part": [
        {
          "name": "type",
          "valueCode": "delete"
        },
        {
          "name": "path",
          "valueString": "Patient.active"
        }
      ]
    },
    {
      "name": "operation",
      "part": [
        {
          "name": "type",
          "valueCode": "replace"
        },
        {
          "name": "path",
          "valueString": "Patient.gender"
        },
        {
          "name": "value",
          "valueCode": "female"
        }
      ]
    },
    {
      "name": "operation",
      "part": [
        {
          "name": "type",
          "valueCode": "insert"
        },
        {
          "name": "path",
          "valueString": "Patient.name"
        },
        {
          "name": "index",
          "valueInteger": 0
        },
        {
          "name": "value",
          "valueHumanName": {
            "family": "Family"
          }
        }
      ]
    }
  ]
}

The Patient resource can be either empty or look as follows:

{
	"resourceType": "Patient",
	"active": false,
	"name": [
		{
			"family": "Test"
		}
	],
	"gender": "male",
	"id": "0e302b42-d9a8-468d-a5c0-dea6ade9811b",
	"meta": {
		"versionId": "16779e39-7164-4e0a-a4d8-8d00aab42426",
		"lastUpdated": "2023-10-19T17:03:05.835Z"
	}
}

Medplum returns the following OperationOutcome:

{
	"resourceType": "OperationOutcome",
	"issue": [
		{
			"severity": "error",
			"code": "invalid",
			"details": {
				"text": "patch.map is not a function"
			}
		}
	],
	"extension": [
		{
			"url": "https://medplum.com/fhir/StructureDefinition/tracing",
			"extension": [
				{
					"url": "requestId",
					"valueUuid": "57c13314-f51c-4c01-af65-be10fe2dd1bc"
				},
				{
					"url": "traceId",
					"valueUuid": "5d99bbf5-5e24-4696-8e0b-ff245f0cdbd6"
				}
			]
		}
	]
}

Could you tell me what is going wrong? Is this a bug?

The same request works with the HAPI FHIR server, so I assume the request is correct, but please tell me if it is actually incorrect.

Thank you!

[codyebberson]

Hi @FlixCoder - thanks for submitting.

It looks like your request uses "FHIRPatch Operations", which we currently do not support.

According to the FHIR spec, PATCH includes 3 different patch formats:

https://hl7.org/fhir/r4/http.html#patch

The body of a PATCH operation SHALL be either:

• a JSON Patch document with a content type of application/json-patch+json
• an XML Patch document with a content type of application/xml-patch+xml
• a FHIRPath Patch parameters resource with FHIR Content Type

The Medplum FHIR server currently only supports JSONPatch input.

Here is your request converted into JSONPatch:

[
  {
    "op": "add",
    "path": "/birthDate",
    "value": "2021-02-01"
  },
  {
    "op": "remove",
    "path": "/active"
  },
  {
    "op": "replace",
    "path": "/gender",
    "value": "female"
  },
  {
    "op": "add",
    "path": "/name/0",
    "value": {
      "family": "Family"
    }
  }
]

Let me investigate how hard it would be to add the "FHIRPath Patch" support.