Glad to hear!

Depending on the length of the incoming request, you may hit the length of the Stream Read Buffer. See my updated code for larger messages as you may need to loop your read() statement,

cheers :)

Hi Craig,

ImportFromString returns an HL7 Message, it does not populate an existing instance of EnsLib.HL7.Message.

Moreover, make sure that you are reading the entire message with %request.Content.Read, you'll probably want to wrap that in a loop.

Here is the code I get to work on my instance (2017.1)

SET tContent = %request.Content.Read()
WHILE '%request.Content.AtEnd {
SET tContent = tContent + %request.Content.Read()
SET tReq = {}.%FromJSON(tContent)
SET tInput = tReq.Message
// Remove your %New() statement and set tMsg like this
SET tMsg = ##class(EnsLib.HL7.Message).ImportFromString(tInput)
// Then you can either set the doctype manually or use PokeDocType()
// ...

To use FHIR in HealthConnect you will probably want to start with the installer kits. Each of these will add some bits and pieces of functionality to your current working production:

For example, to install a foundation namespace and add FHIR STU3 support to it:

SET nNamespace = "FHIR"

// Switch to the HSLIB so we can call our installer methods

// Make the new namespace
SET sc = ##class(HS.HC.Util.Installer).InstallFoundation(nNamespace)
THROW:$$$ISERR(sc) ##class(%Exception.StatusException).CreateFromStatus(sc)

// Add in all of the FHIR components and create a web app
SET sc = ##class(HS.HC.Util.Installer.Kit.FHIR.HealthConnect).Add( , nNamespace, "STU3", "/csp/healthshare/" _ nNamespace _ "/fhir/stu3", "/csp/healthshare/" _ nNamespace _ "/fhir-oidc/stu3")
THROW:$$$ISERR(sc) ##class(%Exception.StatusException).CreateFromStatus(sc)

Once you have this installed, you can use a custom business process to coordinate all of the downstream calls to the external systems. For example, your production might request downstream resources and construct a FHIR response bundle from them.

You can change the header keys of a %Net.HttpRequest

// Make Request
  SET tHttpRequest=##class(%Net.HttpRequest).%New()

  // Set header
  SET tSC = tHttpRequest.SetHeader("Content-Type", "text/plain")

  // Check for Errors
  THROW:$$$ISERR(tSC) ##class(%Exception.StatusException).CreateFromStatus(tSC)

Thus, to put this all together;

  1. Extend the EnsLib.HL7.Operation.HTTPOperation
  2. Copy the SendMessage method from the super EnsLib.HL7.HTTPOperation
  3. Make a small change to set the header after the first line.
// Sample Code, Not Complete
Class Niko.EnsLib.HL7.Operation.HTTPOperation Extends EnsLib.HL7.Operation.HTTPOperation

Method SendMessage(pMsgOut As EnsLib.HL7.Message, Output pMsgIn As EnsLib.HL7.Message, pExpectedSequenceNumber As %String) As %Status
    Set pMsgIn=$$$NULLOREF, tHttpRequest=##class(%Net.HttpRequest).%New(), tHttpRequest.WriteRawMode=1
    // Add these two lines after the firt in SendMessage. Change the content type to your desired header.
    SET tSC = tHttpRequest.SetHeader("Content-Type", "text/plain")
    THROW:$$$ISERR(tSC) ##class(%Exception.StatusException).CreateFromStatus(tSC)

    // Copy the rest of the SendMessage Method from the standard EnsLib.HL7.Operation.HTTPOperation