PowerShell Default value not working - powershell

Question

I'm trying to feed my function with some variables and when no variable is given it should use a default value of 30 for OlderThanDays. For one reason or another this is not working out as I'd expected.
I fixed my problem in the ForEach loop by using if($_.B -ne $null) {$OlderThanDays=$_.B} else {$OlderThanDays="30"} But I don't think this is best practice. Can anyone tell me why [Int]$OlderThanDays=30 isn't working?
Problem: When adding a line in my csv-file without defining the OlderThanDaysvariable, the default of 30 days is not used and the files are just deleted...
Thank you for your help.
CSV file:
# Correct input formats are:
#
# ServerName, LocalPath, OlderThanDays
# Ex: server, E:\SHARE\Target, 10
# Ex: server, E:\CBR\SHARE\Target
#
# UNC-Path, OlderThanDays
# Ex: \\domain\SHARE\Target, 20
# Ex: \\domain\Target
#
# If no 'OlderThanDays' is provided, a default of 30 days will be used
# Commenting out can be done with '#'
# ______________________________________________________________________
SERVER1, E:\SHARE\Target
\\domain\SHARE\Target2
Full script:
#__________________________________________________________________________________________________________________________________
$ImportFile = "S:\Input\Scheduled Task\Auto_Clean.csv"
$Password = cat "S:\Input\pwd.txt" | ConvertTo-SecureString -Force
$UserName = "domain\me"
#__________________________________________________________________________________________________________________________________
# Scriptblock for running the function in a job
$JobCall = {
# Function that removes files older than x days in all subfolders
Function Delete-OldFiles {
[CmdletBinding(SupportsShouldProcess=$True)]
Param(
[Parameter(Mandatory=$True,Position=1)]
[ValidateScript({Test-Path $_})]
[String]$Target,
[Parameter(Mandatory=$False,Position=2)]
[Int]$OlderThanDays=30,
[Parameter(Mandatory=$False,Position=3)]
[String]$Server,
[switch]$CleanFolders
)
#__________________________________________________________________________________________________________________________________
# Create logfile
$TempDate = (get-date).ToString("dd-MM-yyyy")
$TempFolderPath = $Target -replace '\\','_'
$TempFolderPath = $TempFolderPath -replace ':',''
$TempFolderPath = $TempFolderPath -replace ' ',''
$script:LogFile = "\\DEUSTHEIDIT02\Log\Scheduled Task\Auto_Clean\$Server - $TempFolderPath - $TempDate.log"
#__________________________________________________________________________________________________________________________________
# Check the version of PowerShell
if ($PSVersionTable.PSVersion.Major -ge "3") {
# PowerShell 3+ Remove files older than (FASTER)
Get-ChildItem -Path $Target -Recurse -File |
Where-Object { $_.CreationTime -lt (Get-Date).AddDays(-$OlderThanDays) } |
ForEach {
$Item = $_.FullName
Remove-Item $Item -Recurse -Force -ErrorAction SilentlyContinue
# Log succes/failure
$Timestamp = (Get-Date).ToShortDateString()+" | "+(Get-Date).ToLongTimeString()
if (Test-Path $Item) {
"$Timestamp | FAILLED: $Server $Item (IN USE)"
}
else {
"$Timestamp | REMOVED: $Server $Item"
}
} | Tee-Object $LogFile -Append -Verbose}
Else {
# PowerShell 2 Remove files older than
Get-ChildItem -Path $Target -Recurse |
Where-Object { !$_.PSIsContainer -and $_.CreationTime -lt (Get-Date).AddDays(-$OlderThanDays) } |
ForEach {
$Item = $_.FullName
Remove-Item $Item -Recurse -Force -ErrorAction SilentlyContinue
# Log succes/failure
$Timestamp = (Get-Date).ToShortDateString()+" | "+(Get-Date).ToLongTimeString()
if (Test-Path $Item) {
Write-Host "$Timestamp | FAILLED: $Server $Item (IN USE)"
"$Timestamp | FAILLED: $Server $Item (IN USE)"
}
else {
Write-Host "$Timestamp | REMOVED: $Server $Item"
"$Timestamp | REMOVED: $Server $Item"
}
} | Out-File $LogFile -Append }
#__________________________________________________________________________________________________________________________________
# Switch -CleanFolders deletes empty folders older than x days
if ($CleanFolders) {
# Check the version of PowerShell
if ($PSVersionTable.PSVersion.Major -ge "3") {
# PowerShell 3+ Remove empty folders older than (FASTER)
Get-ChildItem -Path $Target -Recurse -Force -Directory -ErrorAction SilentlyContinue |
Where-Object { $_.CreationTime -lt (Get-Date).AddDays(-$OlderThanDays) } |
Where-Object { (Get-ChildItem -Path $_.FullName -Recurse -Force -File) -eq $null } |
ForEach {
$Item = $_.FullName
Remove-Item $Item -Recurse -Force -ErrorAction SilentlyContinue
# Log succes/failure
$Timestamp = (Get-Date).ToShortDateString()+" | "+(Get-Date).ToLongTimeString()
if (Test-Path $Item) {
"$Timestamp | FAILLED: $Server $Item (IN USE)"
}
else {
"$Timestamp | REMOVED: $Server $Item"
}
} | Tee-Object $LogFile -Append
}
else {
# PowerShell 2 Remove empty folders older than
Get-ChildItem -Path $Target -Recurse -Force -ErrorAction SilentlyContinue |
Where-Object { $_.PSIsContainer -and (Get-ChildItem -Path $_.FullName -Recurse -Force | Where-Object { !$_.PSIsContainer }) -eq $null } |
Where-Object { $_.CreationTime -lt (Get-Date).AddDays(-$OlderThanDays) } |
ForEach {
$Item = $_.FullName
Remove-Item $Item -Recurse -Force -ErrorAction SilentlyContinue
# Log succes/failure
$Timestamp = (Get-Date).ToShortDateString()+" | "+(Get-Date).ToLongTimeString()
if (Test-Path $Item) {
Write-Host "$Timestamp | FAILLED: $Server $Item (IN USE)"
"$Timestamp | FAILLED: $Server $Item (IN USE)"
}
else {
Write-Host "$Timestamp | REMOVED: $Server $Item"
"$Timestamp | REMOVED: $Server $Item"
}
} | Out-File $LogFile -Append
}
}
}
# Lact command of the ScriptBlock: Call the magic to happen
Delete-OldFiles $args[0] $args[1] $args[2] -CleanFolders:$args[3]
}
#__________________________________________________________________________________________________________________________________
# Read input file and ignore all lines starting with #
$File = (Import-Csv -Path $ImportFile -Header "A", "B", "C", "D" | Where { $_.A -NotLike "#*" } )
#__________________________________________________________________________________________________________________________________
# If the UNC Path is provided we will run the script locally else it wil be run on the remote server as a job
Foreach ($_ in $File) {
# Define input format & default values
if ($_.A -like "\\*") {
$Server="UNC"
$Target=$_.A
$OlderThanDays=$_.B
$CleanFolders=$_.C
}
else {
$Server=$_.A
$Target=$_.B
$OlderThanDays=$_.C
$CleanFolders=$_.D
}
# Call the scriptblock with the function to run locally or on the remote server
if ($Server -eq "UNC")
{
Write-Host "UNC Path detected: $Target, $OlderThanDays" -ForegroundColor Yellow
Start-Job -ScriptBlock $JobCall -ArgumentList ($Target, $OlderThanDays, $Server) -Name DelFiles
}
else
{
Write-Host "Local path detected: $Server, $Target, $OlderThanDays" -ForegroundColor Cyan
$Credentials = New-Object System.Management.Automation.PSCredential -ArgumentList $UserName,$Password
Invoke-Command -ScriptBlock $JobCall -ArgumentList ($Target, $OlderThanDays, $Server) -ComputerName "$Server.domain" -Authentication Credssp -Credential $Credentials -AsJob -JobName DelFiles
# Delete empty folders: Invoke-Command -ScriptBlock $JobCall -ArgumentList ($Target, $OlderThanDays, $Server, $true) -ComputerName "$Server.domain" -Authentication Credssp -Credential $Credentials -AsJob -JobName DelFiles
}
}

Answer 1

The parameter can't be both Mandatory and have default value. Former is checked first, and if it's set to $true, than default value is simply ignored. If you want to make sure that users can't specify empty value, just use [ValidateNotNullorEmpty()] validation, and make parameter optional.

Answer 2

So I had a similar problem. After months keeping a module with personal functions for day-to-day activities making extensive use of default values and, in many cases, mandatory parameters with initialized default values, suddenly my functions stopped working.
After writing a new one, calling it with explicit parameters would result in the parameters values being empty in the function execution context.
After restarting powershell console for some times I decided to reboot the machine, and everything went back to normal. Go figure.