Nested zip contents listing - powershell

Question

I've been working on a little side project of listing files compressed in nested zip files.
I've cooked up a script that does just that, but only if the depth of zip files is known.
In in example below the zip file has additional zips in it and then anthoer in one of them.
Add-Type -AssemblyName System.IO.Compression.Filesystem
$path = "PATH"
$CSV_Path = "CSV_PATH"
$zipFile = Get-ChildItem $path -recurse -Filter "*.zip"
$rootArchive = [System.IO.Compression.zipfile]::OpenRead($zipFile.fullname)
$rootArchive.Entries | Select #{l = 'Source Zip'; e = {} }, #{l = "FullName"; e = { $_.FullName.Substring(0, $rootArchive.Fullname.Lastindexof('\')) } }, Name | Export-csv $CSV_Path -notypeinformation
$archivesLevel2 = $rootArchive.Entries | Where { $_.Name -like "*.zip" }
foreach ($archive in $archivesLevel2)
{
(New-object System.IO.Compression.ZipArchive ($archive.Open())).Entries | Select #{l = 'Source Zip'; e = { $archive.name } }, #{l = "FullName"; e = { $archive.FullName.Substring(0, $_.Fullname.Lastindexof('\')) } }, Name | Export-Csv $CSV_Path -NoTypeInformation -append;
New-object System.IO.Compression.ZipArchive($archive.Open()) -OutVariable +lastArchiveLevel2
}
$archivesLevel3 = $lastArchiveLevel2.entries | Where { $_.Name -like "*.zip" }
foreach ($archive in $archivesLevel3)
{
(New-Object System.IO.Compression.ZipArchive ($archive.Open())).Entries | Select #{l = 'Source Zip'; e = { $archive.name } }, #{l = "FullName"; e = { $archive.FullName.Substring(0, $_.Fullname.Lastindexof('\')) } }, Name | Export-Csv $CSV_Path -NoTypeInformation -append
}
What I ask of you is to help me modify this to accomodate an unknown depth of inner zip files. Is that even possible?

Answer 1

Here's an example on how to do it using a Queue object, which allow you to recursively go through all depths of your zip file in one go.
As requested, here are some comments to explain what is going on.
Add-Type -AssemblyName System.IO.Compression.Filesystem
$path = "PATH"
$CSV_Path = "CSV_PATH"
$Queue = [System.Collections.Queue]::New()
$zipFiles = Get-ChildItem $path -recurse -Filter "*.zip"
# All records will be stored here
$Output = [System.Collections.Generic.List[PSObject]]::new()
# Main logic. Used when looking at the root zip and any zip entries.
# ScriptBlock is used to prevent code duplication.
$ProcessEntries = {
Param($Entries)
$Entries | % {
# Put all zip in the queue for future processing
if ([System.IO.Path]::GetExtension($entry) -eq '.zip') { $Queue.Enqueue($_) }
# Add a Source Zip property with the parent zip since we want this informations in the csv export and it is not available otherwise.
$_ | Add-Member -MemberType NoteProperty -Name 'Source Zip' -Value $zip.name
# Every entries, zip or not, need to be part of the output
$output.Add($_)
}
}
# Your initial Get-ChildItem to find zip file implicate there could be multiple root zip files, so a loop is required.
Foreach ($zip in $zipFiles) {
$archive = [System.IO.Compression.zipfile]::OpenRead($zip.fullname)
# The $ProcessEntries scriptblock is invoked to fill the Queue and the output.
. $ProcessEntries $archive.Entries
# Should the Zip file have no zip entries, this loop will never be entered.
# Otherwise, the loop will continue as long as zip entries are detected while processing any child zip.
while ($Queue.Count -gt 0) {
# Removing item from the queue to avoid reprocessing it again.
$Item = $Queue.Dequeue()
$archive = New-object System.IO.Compression.ZipArchive ($Item.open())
# We call the main scriptblock again to fill the queue and the output.
. $ProcessEntries $archive.Entries
}
}
$Output | Select 'Source Zip', FullName, Name | Export-Csv $CSV_Path -NoTypeInformation
References
Queue

Answer 2

Here you have a little example of how recursion would look like, basically, you loop over the .Entries property of ZipFile and check if the extension of each item is .zip, if it is, then you pass that entry to your function.
EDIT: Un-deleting this answer mainly to show how this could be approached using a recursive function, my previous answer was inaccurate. I was using [ZipFile]::OpenRead(..) to read the nested .zip files which seemed to work correctly on Linux (.NET Core) however it clearly does not work when using Windows PowerShell. The correct approach would be to use [ZipArchive]::new($nestedZip.Open()) as Sage Pourpre's helpful answer shows.
using namespace System.IO
using namespace System.IO.Compression
function Get-ZipFile {
[cmdletbinding()]
param(
[parameter(ValueFromPipeline)]
[object]$Path,
[parameter(DontShow)]
[int]$Nesting = -1
)
begin { $Nesting++ }
process {
try
{
$zip = if(-not $Nesting) {
[ZipFile]::OpenRead($Path)
}
else {
[ZipArchive]::new($Path.Open())
}
foreach($entry in $zip.Entries) {
[pscustomobject]#{
Nesting = $Nesting
Parent = $Path.Name
Contents = $entry.FullName
}
if([Path]::GetExtension($entry) -eq '.zip') {
Get-ZipFile -Path $entry -Nesting $Nesting
}
}
}
catch
{
$PSCmdlet.WriteError($_)
}
finally
{
if($null -ne $zip) {
$zip.Dispose()
}
}
}
}
Get-ChildItem *.zip | Get-ZipFile