Calculate the hash of a file longer than 256 characters? - powershell

Question

I am using Boe Prox's script to print a list of all the files and folders in a directory. I need Prox's script (as opposed to other windows print directory commands) because it uses robocopy to print filepaths longer than 260 characters.
My problem is, I also want the filehash to be printed alongside the file name. I have modified the script to obtain hashes (please see below) and it generally works except when the filepath is longer than 260 characters. Long filepaths get a blank in the hash column of the final output.
Research I have done:
According to this stackoverflow question, Robocopy has several switches that can be modified. I have scoured Boe's blog, as well as the list of robocopy commands, but there is nothing about a filehash switch.
Attempts to fix the problem:
I have also tried to modify the syntax of the filehash to make it more in line with the rest of the script ie. Hash = $matches.Hash
(this returns all blanks in place of the filehashs)
I tried taking off the part of the regex that seems to specify an item rather than the content of the item ie:If ($_.Trim() -match "^(?<Children>\d+)\s+") {
(this leads to the error code WARNING: Cannot bind argument to parameter 'Path' because it is null.)
I'm pretty hopeful that this can happen though: comments in Boe's original script includes the line: "Version 1.1 -Added ability to calculate file hashes"
Here's is my (partially working script):
Function Get-FolderItem {
[cmdletbinding(DefaultParameterSetName='Filter')]
Param (
[parameter(Position=0,ValueFromPipeline=$True,ValueFromPipelineByPropertyName=$True)]
[Alias('FullName')]
[string[]]$Path = $PWD,
[parameter(ParameterSetName='Filter')]
[string[]]$Filter = '*.*',
[parameter(ParameterSetName='Exclude')]
[string[]]$ExcludeFile,
[parameter()]
[int]$MaxAge,
[parameter()]
[int]$MinAge
)
Begin {
$params = New-Object System.Collections.Arraylist
$params.AddRange(#("/L","/E","/NJH","/BYTES","/FP","/NC","/XJ","/R:0","/W:0","T:W"))
If ($PSBoundParameters['MaxAge']) {
$params.Add("/MaxAge:$MaxAge") | Out-Null
}
If ($PSBoundParameters['MinAge']) {
$params.Add("/MinAge:$MinAge") | Out-Null
}
}
Process {
ForEach ($item in $Path) {
Try {
$item = (Resolve-Path -LiteralPath $item -ErrorAction Stop).ProviderPath
If (-Not (Test-Path -LiteralPath $item -Type Container -ErrorAction Stop)) {
Write-Warning ("{0} is not a directory and will be skipped" -f $item)
Return
}
If ($PSBoundParameters['ExcludeFile']) {
$Script = "robocopy `"$item`" NULL $Filter $params /XF $($ExcludeFile -join ',')"
} Else {
$Script = "robocopy `"$item`" NULL $Filter $params"
}
Write-Verbose ("Scanning {0}" -f $item)
Invoke-Expression $Script | ForEach {
Try {
If ($_.Trim() -match "^(?<Children>\d+)\s+(?<FullName>.*)") {
$object = New-Object PSObject -Property #{
FullName = $matches.FullName
Extension = $matches.fullname -replace '.*\.(.*)','$1'
FullPathLength = [int] $matches.FullName.Length
Length = [int64]$matches.Size
FileHash = (Get-FileHash -Path $matches.FullName).Hash
Created = (Get-Item $matches.FullName).creationtime
LastWriteTime = (Get-Item $matches.FullName).LastWriteTime
}
$object.pstypenames.insert(0,'System.IO.RobocopyDirectoryInfo')
Write-Output $object
} Else {
Write-Verbose ("Not matched: {0}" -f $_)
}
} Catch {
Write-Warning ("{0}" -f $_.Exception.Message)
Return
}
}
} Catch {
Write-Warning ("{0}" -f $_.Exception.Message)
Return
}
}
}
}
Get-FolderItem "C:\TestingFileFolders"

Answer 1

In Windows PowerShell, you can prepend \\?\ to the full path and read the file:
Get-FileHash -Path "\\?\$($matches.FullName)"