Utilidad para descargar mensajes de una producción

Hola a todos! 

Comparto una pequeña utilidad (servicio REST) para descargar mensajes de una producción de interoperabilidad como ficheros.

Sólo necesitas:
1. Crear una aplicación web en el Portal de Gestión (e.g. /downloadmsg) que tenga configurado DispatchClass=Util.DownloadMsg.
2. Llamar a la utilidad pasándole el namespace y el identificador de cabecera del mensaje a descargar.
http://localhost:52773/downloadmsg/ns/dev/msgid/17441

/// 
/// Util to download messages given a message header id
/// 
/// Setup:
/// 1. Create a webapplication (e.g. /downloadmsg) and set DispatchClass=Util.DownloadMsg
/// 2. Go to http://localhost:52773/downloadmsg/ns/user/msgid/19 to download the message reference by header 19
Class Util.DownloadMsg Extends %CSP.REST
{

XData UrlMap [ XMLNamespace = "http://www.intersystems.com/urlmap" ]
{
<Routes>
    <Route Url="/ns/:ns/msgid/:msgId" Method="GET" Call="DownloadMessage"/>
</Routes>
}

/// Download a message given a Ens.MessageHeader id
ClassMethod DownloadMessage(ns As %String, msgId As %String = "") As %Status
{
    set ret = $$$OK
    set currentNs = $namespace

    try {
        set $namespace = ns
        $$$ThrowOnError(..ExportMsgToStream(msgId, .stream, .filename))

        // set headers to download stream as filename
        do %response.SetHeader("Content-Type", "application/octet-stream")
        do %response.SetHeader("Content-Disposition", "attachment; filename="""_filename_"""")
        do %response.SetHeader("Content-Length", stream.Size)
        do stream.Rewind()
        do stream.OutputToDevice()

    } catch ex {
        set ret = ex.AsStatus()
    }

    // restore namespace
    set $namespace = currentNs

    quit ret
}

/// Export a message to stream given a Ens.MessageHeader id
ClassMethod ExportMsgToStream(msgId As %String, Output stream As %Stream.Object, Output filename As %String) As %Status
{
    set ret = $$$OK
    try {
        // stream
        set stream = ##class(%Stream.GlobalCharacter).%New()
        set filename = ""

        // message header
        set headerObj = ##class(Ens.MessageHeader).%OpenId(msgId,,.sc)
        $$$ThrowOnError(sc)

        // message body
        set obj = $classmethod(headerObj.MessageBodyClassName, "%OpenId", headerObj.MessageBodyId)
        set classname = $classname(obj) 

        // output to stream
        if classname="EnsLib.HL7.Message" {
            set sc = $method(obj, "OutputToLibraryStream", .stream)
            $$$ThrowOnError(sc)
            set filename = msgId_".hl7"
        }
        else {
            set writer = ##class(%XML.Writer).%New()
            set writer.Indent=1
            set writer.NoXMLDeclaration=1
            $$$ThrowOnError(writer.OutputToStream(.stream))
            $$$ThrowOnError(writer.RootObject(obj))
            set filename = msgId_".xml"
        }
    } catch ex {
        set ret = ex.AsStatus()
    }
    quit ret
}

}