Hi Eyal,
The idea is to implement a custom FHIR operation as per the docs.
Once you set up the pre-installation subclassing 

(this is where you override those 3 classes:  
HS.FHIRServer.Storage.JsonAdvSQL.Interactions, HS.FHIRServer.Storage.JsonAdvSQL.InteractionsStrategy, HS.FHIRServer.Storage.JsonAdvSQL.RepoManager)

You can create a custom operations class (make sure you reference it in your Interactions class):

Class Testing.Internal.Interactions Extends HS.FHIRServer.Storage.JsonAdvSQL.Interactions
{

Parameter OperationHandlerClass As %String = "Testing.Internal.myOperations";

}

Class Testing.Internal.myOperations Extends HS.FHIRServer.Storage.JsonAdvSQL.BuiltInOperations
{

ClassMethod FHIRTypeOpCustompatienteverything(pService As HS.FHIRServer.API.Service, pRequest As HS.FHIRServer.API.Data.Request, pResponse As HS.FHIRServer.API.Data.Response)
{
        if pRequest.Type="Patient" { 
            if (pRequest.QueryString '= ""){                
                Set fhirService = ##class(HS.FHIRServer.Service).EnsureInstance("/api/internal/test1") //fhir server endpoint               
                Set request = ##class(HS.FHIRServer.API.Data.Request).%New()
                Set request.RequestPath = "/Patient"
                set request.QueryString = pRequest.QueryString
                Set request.RequestMethod = "GET"             
                Do fhirService.DispatchRequest(request, .response)

                Set json = response.Json
                If json.%Get("entry") '="" {
                    Set iter = json.entry.%GetIterator()
                    While iter.%GetNext(.key, .value) { //for each patient entry request an everything
                        
                        Set everythingRequest = ##class(HS.FHIRServer.API.Data.Request).%New()
                        Set everythingRequest.RequestPath = "/Patient/"_value.resource.id_"/$everything"
                        Set everythingRequest.RequestMethod = "GET" 
                        Write !
                        Write "Patient ID: ", value.resource.id, !
                        Do fhirService.DispatchRequest(everythingRequest, .everythingResponse)
                        Write "Everything: ", !, everythingResponse.Json.%ToJSON()
                    }
                }
            }
            else{
                Set pResponse.Json = ##class(HS.FHIRServer.Util.Outcome).Create("information", "No Query String", "informational")
            }

        } 
        set pResponse.Status = 200
}

ClassMethod AddSupportedOperations(pMap As %DynamicObject)
{
	do ##super(pMap) 
	Do pMap.%Set("patient-identifiers-everything", "http://hl7.org/fhir/OperationDefinition/patient-identifiers-everything")
}

}

Hope this helps.

Ari

Hi Gautam,

As it stands your class is not an object class (https://docs.intersystems.com/irislatest/csp/docbook/DocBook.UI.Page.cl…).

In order to instantiate an object, make sure the class inherits from %RegisteredObject or a subclass of it.

We do this in ObjectScript as follows:

Class Sample.Header Extends %RegisteredObject

{

/// your code

}