Calling function from remote script block - powershell

Question

My powershell script is as below. I try to zip a folder at remote machine. I don't want to put Zip function inside ScriptBlock because it will be used in other parts of the script.
function Zip{
param([string]$sourceFolder, [string]$targetFile)
#zipping
}
$backupScript = {
param([string]$appPath,[string]$backupFile)
If (Test-Path $backupFile){ Remove-Item $backupFile }
#do other tasks
$function:Zip $appPath $backupFile
}
Invoke-Command -ComputerName $machineName -ScriptBlock $backupScript -Args $appPath,$backupFile
In $backupScript, it is giving error in $function:Zip line:
+ $function:Zip $appPath $backupFile
+ ~~~~~~~~
Unexpected token '$appPath' in expression or statement.

Answer 1

You have to refer to arguments in a scriptblock like:
$backupScript = {
param([string]$appPath,[string]$backupFile)
If (Test-Path $backupFile){ Remove-Item $backupFile }
#do other tasks
$function:Zip $args[0] $args[1]
}
Invoke-Command -ComputerName $machineName -ScriptBlock $backupScript -Args $appPath,$backupFile
Also, the function will not be known by the target machine, you'll have to define it within the script-block or pass it to the machine.
Here is an example:
How do I include a locally defined function when using PowerShell's Invoke-Command for remoting?
This example puts it in your perspective:
PowerShell ScriptBlock and multiple functions

Answer 2

I would find some way of getting your shared functions onto your server. We have a standard share on all our servers where we deploy common code. When we run code remotely, that code can then reference and use the shared code.