Why is my if statement not being read properly? - powershell

Question

I have a script that backs up a user profile from the local, or remote machine and places it onto a share: $Global:Shared_BackupPath = "\\server\share\". I've been tweaking it a little more and just ended up making some variables into Global variables (not sure if this is the issue - dont see why it would be).
This is the condition:
if(-not (Get-EventSubscriber)){
I tried changing it to -eq $null to see if it would make any difference, but it didn't.
Its just not analyzing the condition properly and goes on to display my message box before all Jobs are done: it's "supposed" to wait till there's no more events and then display the message box:
Register-ObjectEvent -InputObject $job -EventName StateChanged -Action {
#Start-Sleep -Milliseconds 500
$eventSubscriber | Unregister-Event
$eventSubscriber.Action | Remove-Job
if(-not (Get-EventSubscriber)){
$Profile_Sum = Get-ChildItem -Path $Global:BackUp_Path -Recurse |
Measure-Object -Property length -Sum |
Select-Object -ExpandProperty Sum
$Size = try{if($Profile_Sum -lt 1048576){ $TinyByte = " {0:N2}" -f ($Profile_Sum / 1KB) + " KB"; $TinyByte }
elseif($Profile_Sum -gt 1048576 -and $Profile_Sum -lt 1073741824){ $MediumByte = " {0:N2}" -f ($Profile_Sum / 1MB) + " MB"; $MediumByte }
elseif($Profile_Sum -gt 1073741824){ $GiganticByte = " {0:N2}" -f ($Profile_Sum / 1GB) + " GB"; $GiganticByte } } Catch {}
$Begin_Time = Get-Item -Path $Global:BackUp_Path | Select-Object -ExpandProperty LastWriteTime
$End_Time = Get-Date -Format G
Get-Job | Remove-Job
[System.Windows.MessageBox]::Show("Copying Complete!`nStart Time: $Begin_Time `nEnd Time: $End_Time `nProfile Size copied: $Size")
}
} | Out-Null
}
I feel like I may have an idea due to the event itself being registered as a job but, not too sure how to go about it and have it wait until its done with ALL jobs before displaying the messagebox informing me when the copying is complete. Other than that, the script works just fine and anyone reading this can feel free to use it themselves. Heres the full Script:
Function PFL-UserBackUp{
[cmdletbinding()]
Param(
[Parameter(Mandatory=$false,
ValueFromPipeLine=$true,
ValueFromPipeLineByPropertyName=$true)]
[Alias('CN','Computer','server','node')]
[ValidateLength(1, 15)]
[String[]]$ComputerName = $env:COMPUTERNAME )
Begin{
$Global:Shared_BackupPath = "\\server\share\"
}
Process{
Foreach($Computer in $ComputerName){
Try{
$PSSession = New-PSSession -ComputerName $Computer -ErrorAction Stop
[array]$User_List = Invoke-Command -ScriptBlock {
Get-ChildItem -Path "C:\Users" -Exclude Public, Default* |
Sort-Object -Property LastWriteTime -Descending } -Session $PSSession
$userinfo1 = foreach ($user in $User_List.name) {
$userinfo = (net user $user /domain | Select-String "Full Name" -ErrorAction SilentlyContinue) -replace "Full Name ", "" 2>&1 | Out-String -Stream
if ($userinfo.Length -lt 4) { "NO DISPLAY NAME in ADUC" }
elseif($LASTEXITCODE -eq 2) { "ACCOUNT NOT in ADUC" }
elseif($LASTEXITCODE -eq 0) { $userinfo }
else { "Error occured" }
}
$(for($i=0; $i -lt $User_List.Count; $i++){
[pscustomobject]#{
'User Display Name ' = "$($i): $($userinfo1[$i])"
' NAME ' = $User_List.name[$i]
'Last Modified' = "$($User_List.LastWriteTime[$i])"
'Profile Size ' = Try{
$ProfilePath = $User_List.FullName[$i]
$Profile_Sum = Invoke-Command -ScriptBlock {
Get-ChildItem -Path $Using:ProfilePath -Recurse |
Where-Object {$_.PSParentPath -match "Documents|Desktop|Music|Videos|Downloads|Links|Pictures|Favorites|Contacts" -and $_.DirectoryName -notmatch "OneDrive" } |
Measure-Object -Property length -Sum |
Select-Object -ExpandProperty Sum } -Session $PSSession
if($Profile_Sum -lt 1048576){ $TinyByte = " {0:N2}" -f ($Profile_Sum / 1KB) + " KB"; $TinyByte }
elseif($Profile_Sum -gt 1048576 -and $Profile_Sum -lt 1073741824){ $MediumByte = " {0:N2}" -f ($Profile_Sum / 1MB) + " MB"; $MediumByte }
elseif($Profile_Sum -gt 1073741824){ $GiganticByte = " {0:N2}" -f ($Profile_Sum / 1GB) + " GB"; $GiganticByte } #Profile Size
} Catch { "$($Error[0].Exception.Message.Split('.')[2].Trim())!" }
}
} ) | Out-Host
Write-Host "Press 'Q' to quit."
$ii = Read-Host -Prompt "Enter Number of Profile to Back-Up"
$i = $ii.Trim() -split ","
if([String]::IsNullOrEmpty($i) -eq $true) { "Null string"; Break }
elseif($i.ToLower() -like "q*") {"Q was selected. Stopping script."; Break }
<#
" "
" Following Profiles will be Saved:"
" ------------------------------------"
foreach($i in $index) { "$($i.trim()): $($userinfo1[$i])" }
" "
$Confirm = Read-Host -Prompt "Are you sure you want to continue? [Y/N]"
if($Confirm.ToLower().TrimStart() -like "n*" -or $Confirm.ToLower() -like "q*"){Break}
if([String]::IsNullOrEmpty($Confirm.Trim()) -eq $true) { "Null string"; Break }#>
$Profile_Path = "C:\Users\$($User_List.name[$i])"
$Literal_Name = $userinfo1[$i].Replace('/','-')
$Global:BackUp_Path = "$Global:Shared_BackupPath$Literal_Name"
$Test_Path = Test-Path -Path $Global:BackUp_Path
if($Test_Path -eq $false){
New-Item -Path $Global:BackUp_Path -ItemType Directory | Out-Null
Start-Process $Global:BackUp_Path}
elseif($Test_Path -eq $true){
$Find_OldName = Get-ChildItem -Path "$Global:Shared_BackupPath" -Filter "$Literal_Name" -Directory |
Sort-Object -Property LastWriteTime -Descending |
Select-Object -ExpandProperty BaseName -First 1
$New_PathName = $Find_OldName + "1"
New-Item -Path "$Global:Shared_BackupPath" -Name $New_PathName -ItemType Directory -OutVariable Global:BackUp_Path | Out-Null #Global:BackUp_Path variable declared
$Global:BackUp_Path = $Global:BackUp_Path.FullName
Start-Process $Global:BackUp_Path}
$Global:Start_Time = Get-Date -Format G
#Favorites Copy
$FireFox_Favorites = "C:\Users\$($User_List.name[$i])\AppData\Roaming\Mozilla\Firefox\Profiles\*.default\places.sqlite"
$Chrome_Favorites = "C:\Users\$($User_List.name[$i])\AppData\Local\Google\Chrome\User Data\Default\Bookmarks"
$Chrome_Favorites2 = "C:\Users\$($User_List.name[$i])\AppData\Local\Google\Chrome\User Data\Default\Bookmarks.bak"
$Sticky_Notes = "C:\Users\$($User_List.name[$i])\AppData\Local\Packages\Microsoft.MicrosoftStickyNotes_8wekyb3d8bbwe\LocalState\plum.sqlite"
$Favorites_Array = #($FireFox_Favorites,$Chrome_Favorites,$Chrome_Favorites2,$Sticky_Notes)
Foreach($File in $Favorites_Array){
$Test_File = Invoke-Command -ScriptBlock { Test-Path -Path $File }
if($Test_File -eq $true){
Copy-Item -Path $File -Destination $Global:BackUp_Path -Force -Recurse -FromSession $PSSession
}
}
#Folders Copy
$Folders = #('Desktop','Documents','Favorites','Links','Downloads','Music','Videos','Pictures','Contacts')
Foreach($Folder in $Folders){
#Create Arugments for seperate thread
$ArgumentsArray = $null
$ArgumentsArray = #()
$ArgumentsArray += "\\$Computer\c$\Users\$($User_List.name[$i])\$Folder"
$ArgumentsArray += $Global:BackUp_Path
$job = Start-Job -ScriptBlock { Copy-Item -Path $args[0] -Destination $args[1] -Force -Recurse } -Name $Folder -ArgumentList $ArgumentsArray
Register-ObjectEvent -InputObject $job -EventName StateChanged -Action {
#Start-Sleep -Milliseconds 500
$eventSubscriber | Unregister-Event
$eventSubscriber.Action | Remove-Job
if(-not (Get-EventSubscriber)){
$Profile_Sum = Get-ChildItem -Path $Global:BackUp_Path -Recurse |
Measure-Object -Property length -Sum |
Select-Object -ExpandProperty Sum
$Size = try{if($Profile_Sum -lt 1048576){ $TinyByte = " {0:N2}" -f ($Profile_Sum / 1KB) + " KB"; $TinyByte }
elseif($Profile_Sum -gt 1048576 -and $Profile_Sum -lt 1073741824){ $MediumByte = " {0:N2}" -f ($Profile_Sum / 1MB) + " MB"; $MediumByte }
elseif($Profile_Sum -gt 1073741824){ $GiganticByte = " {0:N2}" -f ($Profile_Sum / 1GB) + " GB"; $GiganticByte } } Catch {}
$Begin_Time = Get-Item -Path $Global:BackUp_Path | Select-Object -ExpandProperty LastWriteTime
$End_Time = Get-Date -Format G
Get-Job | Remove-Job
[System.Windows.MessageBox]::Show("Copying Complete!`nStart Time: $Begin_Time `nEnd Time: $End_Time `nProfile Size copied: $Size")
}
} | Out-Null
}
" "
Write-Output -InputObject "Copying will be done in background."
Write-Output -InputObject "You will be notified when copying is done."
} catch [System.Management.Automation.Remoting.PSRemotingTransportException]{
"Unable to connect to PC: $Computer `nError: $($Error[0].Exception.Message.Split('.')[2].Trim())!"
}
}
}
}
I removed some information that could get me in trouble but, it's all cosmetics.(:
EDIT: I must be on crack but, everything is working now. Only changes I made was clearing the global variables ($Global:var = $null) before assigning it a value. Thank you all for the suggestions. Another change i made was change Copy-Item to Robocopy instead.

Answer 1

To just answer your question:
Why is my if statement not being read properly?
Just before you evaluate Get-EventSubscriber your are cancelling your event subscription and thus deleting your event subscriber. Get-EventSubscriber therefore returns $null which evaluates to $true, when negated. In conclusion, the code after your if statement will always be executed immediately.
Commented code:
Register-ObjectEvent -InputObject $job -EventName StateChanged -Action {
$eventSubscriber | Unregister-Event # Here you cancel your event subscription
$eventSubscriber.Action | Remove-Job
if (-not (Get-EventSubscriber)) { # Therefore, Get-EventSubscriber returns $null; not $null evaluates to $true
...
The relevant part in the documentation of Unregister-Event:
The Unregister-Event cmdlet cancels an event subscription that was created by using the Register-EngineEvent, Register-ObjectEvent, or Register-WmiEvent cmdlet.
When an event subscription is canceled, the event subscriber is deleted from the session and the subscribed events are no longer added to the event queue. When you cancel a subscription to an event created by using the New-Event cmdlet, the new event is also deleted from the session.