I have a service running that can invoke an external process to modify a text stream before it is returned to the service. The text stream is handed from the service to the external process on stdout and the modified result is read from the service on stdin. The external process (command) can in other words be used as a text "filter". I would like to use a powershell script to modify the text stream. I can successfully launch a script from the service on win 2008r2 using the command "powershell -executionpolicy bypass -noninteractive ./myscript.ps1".

I can make the script return text to the service on stdout using the write-host cmdlet. My problem is that I can't find a way to read the text on stdin in the script. Read-host doesn't seem to work as it requires an interactive shell.

I would like to avoid writing the stdout from the service to a tmp file and read that file in the script as the service is multithreaded (can launch more than one external command at a time) and tmp file management (locking, unique filenames etc) is not desired.

Is this possible or should I use for example Perl for this? Powershell seems compelling as it is preinstalled on all my win 2008 machines.