How to uncompress a 7zip string from/to memory? - powershell

Question

I have a 7zip-compressed string (LZMA2) and I want to unzip that into memory via Powershell without using the file-system, but with no luck. I am able to unzip regular zip-strings, but no 7z-strings. Here a sample code to show my attempt so far:
# define settings for http-client:
Add-Type -AssemblyName System.Net.Http
$handler = [System.Net.Http.HttpClientHandler]::new()
$client = [System.Net.Http.HttpClient]::new($handler)
# get the 7z-compressed EPG-file:
$url = [string]::Concat('http://www.', 'vuplus', '-', 'community.net', '/ryt', 'ec/ryt', 'ecDE_Basic', '.xz')
$result = $client.GetAsync($url).Result
$data = $result.Content.ReadAsStringAsync().Result
# unzip:
$enc = [System.Text.Encoding]::GetEncoding(28591)
$ziparr = $enc.GetBytes($data)
$in = [System.IO.MemoryStream]::new($ziparr)
$mem = [System.IO.MemoryStream]::new()
$mode = [System.IO.Compression.CompressionMode]::Decompress
$zip = [System.IO.Compression.GzipStream]::new($in, $mode)
$zip.CopyTo($mem)
$arr = $mem.ToArray()
$unzippedText = $enc.GetString($arr)
If that is not possible via OS/.net-functions, is there any way to use 7za.dll for such without using the file-system?

Answer 1

I have found a solution by using the dll from the 7zipSharp-Package and the 7z64.dll. Here the code-snippet:
# define settings for http-client:
Add-Type -AssemblyName System.Net.Http
$handler = [System.Net.Http.HttpClientHandler]::new()
$client = [System.Net.Http.HttpClient]::new($handler)
# get the 7z-compressed EPG-file:
$url = [string]::Concat('http://', 'www.vuplus', '-', 'community.net', '/ryt', 'ec/ryt', 'ecDE_Basic', '.xz')
$result = $client.GetAsync($url).Result
$data = $result.Content.ReadAsStreamAsync().Result
# references:
# https://globalcdn.nuget.org/packages/sevenzipsharp.net45.1.0.19.nupkg
# https://github.com/squid-box/SevenZipSharp/raw/dev/SevenZip/7z64.dll
Add-Type -Path "C:\temp\SevenZipSharp.dll"
[SevenZip.SevenZipExtractor]::SetLibraryPath('C:\temp\7z64.dll')
$ex = [SevenZip.SevenZipExtractor]::new($data)
$mem = [System.IO.MemoryStream]::new()
$ex.ExtractFile(0, $mem)
$arr = $mem.ToArray()
$enc = [System.Text.Encoding]::GetEncoding(28591)
$unzippedText = $enc.GetString($arr)