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Pass information between independently running Powershell scrips

Sorry for being wage before. I'll try again:

The circumstances are too complicated to explain, but basically the problem is:

  • how to pass a string (max 20 chars) from one script, to another script running on the same machine.
  • the two scripts are running continuously in the background, on the same machine, under the same user context, but can not be combined.
  • I can not dot-source one script in the other.

I have done it by having one script create a file with the string in it, in a directory monitored by the other script. So when it appears, the other script reads the information. It works, but it feels "dirty". :)

I was wondering if there is a "best practice"-way to pass information between scripts or at least a more elegant way.

Thanks.

Solution

  • There are several ways for enabling two continuously running processes on the same host to communicate with each other, for instance named pipes:

    # named pipe - server
$name = 'foo'
$namedPipe = New-Object IO.Pipes.NamedPipeServerStream($name, 'Out')
$namedPipe.WaitForConnection()

$script:writer = New-Object IO.StreamWriter($namedPipe)
$writer.AutoFlush = $true
$writer.WriteLine('something')
$writer.Dispose()

$namedPipe.Dispose()

    # named pipe - client
$name = 'foo'
$namedPipe = New-Object IO.Pipes.NamedPipeClientStream('.', $name, 'In')
$namedPipe.Connect()

$script:reader = New-Object IO.StreamReader($namedPipe)
$reader.ReadLine()
$reader.Dispose()

$namedPipe.Dispose()

    or TCP sockets:

    # TCP socket - server
$addr = [ipaddress]'127.0.0.1'
$port = 1234

$endpoint = New-Object Net.IPEndPoint ($addr, $port)
$server = New-Object Net.Sockets.TcpListener $endpoint
$server.Start()
$cn = $server.AcceptTcpClient()

$stream = $cn.GetStream()
$writer = New-Object IO.StreamWriter($stream)
$writer.WriteLine('something')
$writer.Dispose()

$server.Stop()

    # TCP socket - client
$server = '127.0.0.1'
$port   = 1234

$client = New-Object Net.Sockets.TcpClient
$client.Connect($server, $port)
$stream = $client.GetStream()

$reader = New-Object IO.StreamReader($stream)
$reader.ReadLine()
$reader.Dispose()

$client.Dispose()