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Binaries

Binary Data

For optimal performance, binaries are stored outside of the FHIR resources themselves, utilizing Azure Blob Storage. This introduces additional steps during the document upload process.

Process

Uploading a DocumentReference to the FHIR server involves a two-step process.

• Create the intended DocumentReference with a placeholder Attachment.
• Using the ID of the created DocumentReference, initiate the Binary Access Write Operation to upload the binary content.

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Example: Binary Access Write Operation

Here is an minimal example of creating a DocumentReference and uploading binary content.

POST /DocumentReference
Content-Type: application/fhir+json

{
  "resourceType": "DocumentReference",
	"subject": {
		"reference": "Patient/123"
	},
  "content": [
    {
      "attachment": {
        "contentType": "application/pdf"
      }
    }
  ]
}

Upon creation of the DocumentReference, the server responds with a Location header and details of the created resource, including the assigned ID.

Location: https://r4.helix.medicaldirector.com/Tenant1/DocumentReference/c6294fe3-177c-465e-a683-5c03b13bf920/_history/1

{
    "resourceType": "DocumentReference",
    "id": "c6294fe3-177c-465e-a683-5c03b13bf920",
    ...
}

The obtained ID is required for the following Binary Access Write Operation. The 'path' parameter specifies a FHIRPath expression to the Attachment element within the DocumentReference resource. The Content-Type header in the HTTP operation serves as the content type for the attachments. It's important to note that this field isn't validated against the placeholder resource and will be overwritten.

POST /DocumentReference/c6294fe3-177c-465e-a683-5c03b13bf920/$binary-access-write?path=DocumentReference.content.attachment
Content-Type: application/pdf

(... binary content ...)

Example: Binary Access Read Operation

The Binary Access Read Operation facilitates the retrieval of binary content from Attachment elements, mirroring the approach used in the preceding write operation.

GET /DocumentReference/c6294fe3-177c-465e-a683-5c03b13bf920/$binary-access-read?path=DocumentReference.content.attachment