Is there a way to pass serializable objects to a PowerShell script with start-process?

Question

I know about PowerShell jobs, but I want to use start-process and pass a serializable object to the new powershell process. Is there any way to do this?

It seems that using start-process you have to provide a string argument list which won't cut it for me. I'm trying to get a PSCredential from one process to another (or a SecureString, I'll take either one). Maybe this circumvents security.

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UPDATE - adding the solution I used after seeing help from others (using solution from @PetSerAl)

I wrote two test scripts: a parent script and a child script. The parent script calls the child script.

Parent Script:

$securePassword = ConvertTo-SecureString "testpassword" -AsPlainText -Force
$cred = New-Object PSCredential("testuser", $securePassword)
$credSerial = [Convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes([Management.Automation.PSSerializer]::Serialize($cred)))

$psFile = "C:\repos\Test\PowerShell Scripts\KirkTestChild.ps1"
$p1 = "-someparam ""this is a test!!!"""
$p2 = "-cred ""$credSerial"""

$proc = Start-Process PowerShell.exe -PassThru:$true -Argument "-File ""$($psFile)""", $p1, $p2
Write-Host "ID" $proc.Id
Write-Host "Has Exited" $proc.HasExited

Start-Sleep -Seconds 15
Write-Host "Has Exited" $proc.HasExited

Child Script:

Param(
    $someParam,
    $cred
)

Write-Host "someParam: $($someParam)"
Write-Host "cred (raw): $($cred)"
$realCred=[Management.Automation.PSSerializer]::Deserialize([Text.Encoding]::UTF8.GetString([Convert]::FromBase64String($cred)))
Write-Host "cred user: $($realCred.UserName)"
Write-Host "start"
Start-Sleep 5
Write-Host "ending"
Start-Sleep 5

Answer 1

Yes. As PetSerAl wrote in a comment, you can use the PSSerializer class to handle that:

$ser = [System.Management.Automation.PSSerializer]::Serialize($credential)

$cred = [System.Management.Automation.PSSerializer]::Deserialize($ser)

I don't know if your process will understand the CliXML format though; you don't specify what process you're starting.

Since this will produce XML which is multi-line, it may not work to pass this to a process as a parameter which is why PetSerAl is including the code to Base64 encode the resulting XML.

You might also be able to pass the XML over STDIN instead of Base64 encoding, which also ensures that you won't accidentally hit the command line size limit.