Hello Marc Mundt,

ITB.HL7.BS.XMLService code is the following:

/// HL7 XML services common class
Class ITB.HL7.BS.XMLService Extends (Ens.BusinessService, ITB.HL7.XMLHost)
{

/// Location and Revision of this file in Perforce (Auto-updating)
Parameter SrcVer = "$Id$";

Property UseAckCommitCodes As %Boolean [ InitialExpression = 1 ];

Property BadMessageHandler As %String(MAXLEN = 1000);

/// Name of the element to send the incoming XML stream received by this Service if message is processed OK
Property XMLInputHandler As %String(MAXLEN = 1000);

/// Colon-separated LocalFacility:LocalApplication:MessageStructure codes representing this (receiving) facility, application, returning MessageStructure, AcceptAcknowledgmentType and ApplicationAcknowledgmentType<br/>
/// These are used in constructing reply ACK message headers as SendingFacility, SendApplication and MessageStructure. <br/>
/// The '@' symbol represents using the corresponding field from the incoming message. <br/>
/// If your ID must contain a literal @ symbol, escape it with backslash: '\@'
Property LocalFacilityApplication As %String [ InitialExpression = "ISC:EnsembleHL7:ACK:NE:NE" ];

/// Strip namespace in HL7 XML (ACK message).
Property StripNamespace As %Boolean [ InitialExpression = 1 ];

/// Control of ACK handling; options: <br/>
/// - Never : Do not send back any ACK <br/>
/// - Immediate : Send back (commit) ACK reply message immediately upon receipt of the inbound message <br/>
/// - Application : If message passes validation, wait for ACK from target config item and forward it back when it arrives <br/>
Property AckMode As %String(DISPLAYLIST = ",Never,Immediate,Application", VALUELIST = ",Never,Immed,App") [ InitialExpression = "Immed", Required ];

/// Names the target(s) from which an ACK response should be forwarded back to the caller, if the AckMode="Application".
Property ResponseFrom As %String(MAXLEN = 1000);

Parameter SETTINGS = "StripNamespace,LocalFacilityApplication,AckMode,ResponseFrom::selector?context={Ens.ContextSearch/ProductionItems?targets=1&productionName=@productionId},UseAckCommitCodes,TargetConfigNames:Basic:selector?multiSelect=1&context={Ens.ContextSearch/ProductionItems?targets=1&productionName=@productionId},BadMessageHandler:Basic:selector?context={Ens.ContextSearch/ProductionItems?targets=1&productionName=@productionId},XMLInputHandler:Basic:selector?context={Ens.ContextSearch/ProductionItems?targets=1&productionName=@productionId},SearchTableClass::selector?context={Ens.ContextSearch/SearchTableClasses?host=EnsLib.HL7.Service.Standard},MessageSchemaCategory:Basic:selector?context={Ens.ContextSearch/SchemaCategories?host=EnsLib.HL7.Service.Standard},AlertGracePeriod:Alerting";

/// HL7 XML (Stream) process input
Method StreamProcessInput(pInput As %Stream.Object, Output pOutput As %Stream.Object, pSendAck As %Boolean = 0, pCallTargets As %Boolean = 1, Output pER7 As EnsLib.HL7.Message) As %Status
{
    set ret = $$$OK
    
    try {
        // convert XML input to ER7
        set tER7 = ##class(ITB.HL7.Util.Convert).XMLToER7(pInput,.tSC,..MessageSchemaCategory)
        if $$$ISERR(tSC) $$$ThrowStatus(tSC)
        set pER7 = tER7
        
        // send ACK
        if pSendAck,..AckMode="Immed" {
            set tAckCode = $case(..UseAckCommitCodes, 1:"CA", 0:"AA")
            set tAckER7 = ..GetAck(tER7, tAckCode)
            set tAckXML = ##class(ITB.HL7.Util.Convert).ER7ToXML(tAckER7,.tSC,,,,..StripNamespace)
            if $$$ISERR(tSC) $$$ThrowStatus(tSC)
            set pOutput = tAckXML
        }
        
        // send EnsLib.HL7.Message to targets
        if pCallTargets {
            for i=1:1:$l(..TargetConfigNames, ",") {
                set tTarget=$zstrip($p(..TargetConfigNames,",",i),"<>W")
                if pSendAck,..AckMode="App",..ResponseFrom=tTarget {
                    $$$THROWONERROR(tSC,..SendRequestSync(tTarget, tER7, .tAckER7))
                    set tAckXML = ##class(ITB.HL7.Util.Convert).ER7ToXML(tAckER7,.tSC,,,,..StripNamespace)
                    if $$$ISERR(tSC) $$$ThrowStatus(tSC)
                    set pOutput = tAckXML
                } else {
                    $$$THROWONERROR(tSC,..SendRequestAsync(tTarget, tER7))
                }
            }
        }
        
        // index HL7 in SearchTable
        if ..SearchTableClass'="" {
            set tSC = $zobjclassmethod(..SearchTableClass,"IndexDoc",tER7)
            if $$$ISERR(tSC) $$$LOGERROR("SearchTableClass Error: "_##class(%SYSTEM.Status).GetErrorText(tSC))
        }
        
        // ok. send XML input to XMLInputHandler if any
        do:..XMLInputHandler'="" ..SendStreamToTarget(..XMLInputHandler,pInput)
        
    } catch ex {
        set ret = ex.AsStatus()
        $$$LOGERROR($$$StatusDisplayString(ret))
        
        // error occured. send service input to BadMessageHandler if any
        do:..BadMessageHandler'="" ..SendStreamToTarget(..BadMessageHandler,pInput)
        
        // send alert when HL7 XML has not been processed correctly
        do:..AlertOnError ..SendAlert(##class(Ens.AlertRequest).%New($LB(..%ConfigName,$$$StatusDisplayString(ret))))
    }
    
    quit ret
}

/// Get ACK message for a given HL7 message
Method GetAck(pMsg As EnsLib.HL7.Message, pReplyCode As %String) As EnsLib.HL7.Message
{
    // create ACK and copy the control id to the ack control id
    set tReply = pMsg.NewReplyDocument(,..LocalFacilityApplication)
    set tReply.Source = pMsg.%Id()
    do tReply.SetValueAt(pMsg.GetValueAt("1:10"),"1:10")
    do tReply.SetValueAt($p(..LocalFacilityApplication,":",3),"1:9.3")
    do tReply.SetValueAt($p(..LocalFacilityApplication,":",4),"1:15")
    do tReply.SetValueAt($p(..LocalFacilityApplication,":",5),"1:16")
    
    // MSA segment
    set tMSA=##class(EnsLib.HL7.Segment).%New($LB("",1))
    set tMSA.Separators=tReply.Separators
    do tMSA.SetValueAt("MSA",0)
    do tMSA.SetValueAt(pReplyCode,1)
    do tMSA.SetValueAt(pMsg.GetValueAt("1:10"),2)
    do tReply.AppendSegment(tMSA)
    
    quit tReply
}

/// Send pInput stream to a production target
Method SendStreamToTarget(pTarget As %String, pInput As %Stream.Object) As %Status
{
    set tMsg = ##class(Ens.StreamContainer).%New(pInput)
    set tSC = ..SendRequestAsync(pTarget, tMsg)
    if $$$ISERR(tSC) $$$LOGERROR(##class(%SYSTEM.Status).GetOneErrorText((tSC)))
    quit tSC
}

/// Return an array of connections for drawing lines on the config diagram
ClassMethod OnGetConnections(Output pArray As %String, pItem As Ens.Config.Item)
{
    do ##super(.pArray,pItem)
    
    if pItem.GetModifiedSetting("TargetConfigNames",.tValue) {
        
        set:pItem.GetModifiedSetting("BadMessageHandler",.tBadMessageHandler) tValue=tValue_","_tBadMessageHandler
        set:pItem.GetModifiedSetting("XMLInputHandler",.tXMLInputHandler) tValue=tValue_","_tXMLInputHandler
        
        for i=1:1:$L(tValue,",") {
            set tOne=$zstrip($p(tValue,",",i),"<>W")
            continue:""=tOne
            set pArray(tOne)=""
        }
    }
}

}

GetAck is a "Method"

How should we call it using method syntax, Marc Mundt?

Thanks for your replies

Thanks Eduard for sharing this interesting piece of advice

Why would be better or recommended to use %CSP.REST directly, instead of EnsLib.REST.Service?

Are there any improvements if we use %CSP.REST?

Thanks for your reply

We are grateful Marc for your help,

Thanks for explaining how did you find the cause which was preventing to get the response in POSTMAN