I have a function that flattens directories in parallel for multiple folders. It works great when I call it in a non-pipeline fashion:
$Files = Get-Content $FileList
Merge-FlattenDirectory -InputPath $Files
But now I want to update my function to work both on the pipeline as well as when called off the pipeline. Someone on discord recommended the best way to do this is to defer all processing to the end
block, and use the begin
and process blocks
to add pipeline input to a list. Basically this:
function Merge-FlattenDirectory {
[CmdletBinding()]
param (
[Parameter(Mandatory,Position = 0,ValueFromPipeline)]
[string[]]
$InputPath
)
begin {
$List = [System.Collections.Generic.List[PSObject]]@()
}
process {
if(($InputPath.GetType().BaseType.Name) -eq "Array"){
Write-Host "Array detected"
$List = $InputPath
} else {
$List.Add($InputPath)
}
}
end {
$List | ForEach-Object -Parallel {
# Code here...
} -ThrottleLimit 16
}
}
However, this is still not working on the pipeline for me. When I do this:
$Files | Merge-FlattenDirectory
It actually passes individual arrays of length 1
to the function. So testing for ($InputPath.GetType().BaseType.Name) -eq "Array"
isn't really the way forward, as only the first pipeline value gets used.
My million dollar question is the following:
What is the most robust way in the process block
to differentiate between pipeline input and non-pipeline input? The function should add all pipeline input to a generic list, and in the case of non-pipeline input, should skip this step and process the collection as-is moving directly to the end block.
The only thing I could think of is the following:
if((($InputPath.GetType().BaseType.Name) -eq "Array") -and ($InputPath.Length -gt 1)){
$List = $InputPath
} else {
$List.Add($InputPath)
}
But this just doesn't feel right. Any help would be extremely appreciated.