file name passthrough and extending a class to override a method

I needed to pass through a file with Ensemble but the operation wasn't writing some filenames as given because the  EnsLib.File.PassthroughOperation 'sanitizes' filenames removing characters that are not valid on some operating
systems;
09000655_AEDC_C3344059_A/E_Martin Browne_09000655_201706221018.pdf
09000655_AEDC_C3344059_A#47E_Martin_Browne_09000655_201706221018.pdf

Oh No! It has stripped out my semicolon and ampersand! I need them! (and they are valid filename characters in windows)

I needed a class that ignores the file name parameter and instead writes the destination file with the same name as the source file.

To do this I extended the class EnsLib.File.PassthroughOperation with my own class that overrides the OnMessage() method.

Changing the SETTINGS to remove the File name field from the basic settings in the operation:

Parameter SETTINGS As %String = "-Filename:Basic";

Removing the ..Adapter.CreateTimestamp() function from the line that sets the tFilename variable:

 Set tFilename=..Adapter.CreateTimestamp(##class(%File).GetFilename(pRequest.OriginalFilename),..Filename)

Set tFilename=##class(%File).GetFilename(pRequest.OriginalFilename)

 (thanks to Andrew Harris at the WRC for this excellent tip!)

Andrew provide more excellent advice;

You may still wish to filter out certain characters from the file name, e.g. “/”.  There is a discussion here:
https://stackoverflow.com/questions/457994/what-characters-should-be-restricted-from-a-unix-file-name2.

Sadly I didn't implement this because I am not passing files to another OS.

--

Final version;

/// this version does not modify the filename in any way.
/// Accepts objects of type Ens.StreamContainer and saves the 
/// encapsulated stream data to a file using the File OutboundAdapter.
Class EalingPackage.file.PassthroughOperation Extends EnsLib.File.PassthroughOperation
{

Parameter ADAPTER = "EnsLib.File.OutboundAdapter";

/// Name of file to output the document(s) to.
/// not stripped of characters illegal in target filenames).
/// Timestamping options ignored.
/// only use where source and destination filename rules are consistant. (same OS and OS version)
Property Filename As %String(MAXLEN = 1000, MINLEN = 1) [ InitialExpression = "%f_%Q", Required ];

Parameter SETTINGS As %String = "-Filename:Basic";

Method OnMessage(pRequest As Ens.StreamContainer, Output pResponse As %Persistent) As %Status
{
     Quit:'$IsObject(pRequest.Stream) $$$ERROR($$$EnsErrGeneral,"No Stream contained in StreamContainer Request")
     Set tFilename=##class(%File).GetFilename(pRequest.OriginalFilename)
     Set tSC=..Adapter.PutStream(tFilename, pRequest.Stream)
     Do pRequest.%Save() ; re-save in case PutStream() optimization changed the Stream filename
     Quit tSC
}

}