You can do this with the $CLASSMETHOD function in ObjectScript:

https://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY...

ClassMethod someMethod(className As %String)
{
	set classObject = $CLASSMETHOD(className,"%New")

...
}

This won't help you in the short term, but upcoming versions will include a nice feature to export messages from the message search page. For more details, have a look at this presentation from this year's InterSystems Global Summit.

https://learning.intersystems.com/course/view.php?id=1015

For the short term, most people use the suggestion from @Julian Matthews of adding a new file out business operation and resending the messages to it.

Some business operations that use EnsLib.File.OutboundAdapter will pull the value for %f from a property in the request object. This would allow you to set that property in a DTL before sending it to the business operation.

But, it looks like you're using EnsLib.XML.Object.Operation.FileOperation, which doesn't do this. It uses the class name of the inbound object as the value for %f.

To create a filename programmatically with EnsLib.XML.Object.Operation.FileOperation, you can create a custom class that extends EnsLib.XML.Object.Operation.FileOperation and override the OnMessage() method. 

The relevant line in the standard OnMessage method is this. You can replace this with your custom logic:

    // Create output filename using the class name of the persistent class as the base.
    Set tFilename=..Adapter.CreateFilename($classname(pRequest),..Filename)

The documentation for %Net.HttpRequest has some sample code that should be useful:

From that page:

In order to send parameters on the URL, i.e. when you see a URL like

http://www.demo.com/page.html?PARAM1=TEST&PARAM2=HELLO

You use the SetParam method to add these parameters one by one. For example to get the index page from 
Documatic you do:

    Set httprequest=##class(%Net.HttpRequest).%New()
    Set httprequest.Port=1972
    Do httprequest.SetParam("PAGE","INDEX")
    Do httprequest.Get("/csp/docbook/%CSP.Documatic.cls")
    Do httprequest.HttpResponse.OutputToDevice()

You may also pass the query parameters on the Get call directly too as long as they are correctly escaped.

In addition to setting FetchSize, we can also improve the speed with an optimization to how EnsLib.SQL.GatewayResultSet fetches rows for large result sets.

This optimization is planned to be included in a future product version, but it is possible to do this in current versions with custom code. What version of Ensemble are you using?

Guillaume, do you know who the InterSystems Sales Engineer is for your company? We should discuss this by email and we can get you some sample code.

File operations pull the value for %f from the "Source" property of the EnsLib.EDI.XML.Document object. In your code sample you're creating a new EnsLib.EDI.XML.Document and copying the output from your XSLT transformation into it, but you're not setting Source to anything. As an experiment, try setting Source to a value and confirm that your output file is given that name.

set xmlResultDoc.Source="MyFileName.xml"

If you want %f to use the same filename as the original input file then you'll want to grab the Source value from your original object that was created by the business service and copy it to xmlResultDoc.Source.

The "Context" and "Expression" should be wrapped in quotation marks.

Looking at the generated code, this is probably not possible.

Each context variable becomes a standard property in an auto-generated context class. The "Default Value" becomes the "InitialExpression" attribute of the property. This means the default is assigned by the underlying object framework upon instantiation of the context object rather than by the BPL engine itself.

Class Test2.NewProcess1.Context Extends Ens.BP.Context [ ClassType = persistent, CompileAfter = Test2.NewProcess1, GeneratedBy = Ens.BPL.Compiler.CLS, ProcedureBlock ]
{

Property testvar1 As %String(MAXLEN = 50) [ InitialExpression = "blah" ];

}

Manish,

If you haven't already, please contact the WRC for help with this.
 

Have a look at the separators and framing settings in EnsLib.HL7.Operation.FileOperation. The sixth item in Separators is the segment terminator (carriage return in standard HL7) while Framing lets you change the message terminator (line feed in standard HL7). You can change these to non-standard values if needed.

From the separators documentation linked above:

|^~\&

I see an issue in the first piece of code you posted.

At the top of the method you do this:
set pInput=pRequest.FileStream

But when you write the stream to the file, you do this:
set status=..Adapter.PutStream(..Filename, pInput.Stream)
 
I don't know for certain what type of object pRequest is or pRequest.FileStream, but in the service you posted it looks like pRequest.FileStream is a %Stream.Object.

Method OnProcessInput(pInput As %Stream.Object, Output pOutput As %RegisteredObject) As %Status
...
set pt.filestream=pInput

If pRequest.FileStream is a %Stream.Object, then it won't have a Stream property and passing pInput.Stream to PutStream should fail. Try changing this to:
set status=..Adapter.PutStream(..Filename, pInput)

IIRC "#" means that the character doesn't exist in the chosen font. The default font may not be very complete. You might want to explicitly set the font you're using to one you know contains Cyrillic characters.

Also, in your Zen Report class you can set the encoding as a parameter. This may not be necessary since it should default to UTF-8:
Parameter ENCODING="ISO-8859-1";

I'd suggest contacting the WRC to help look at the problem you're seeing with unwanted characters in the output. EnsLib.RecordMap.Operation.BatchFileOperation does what you've described, so it would be best to get this working for your use case if possible.

Looking at the code you posted...

pRequest.Records.GetAt(1)

This will just get you the first record from the batch. If you want to get a specific field from a record you would want to use something like:

pRequest.Records.GetAt(1).FieldName