PowerShell natively does not contain a CmdLet for creating a GZip file. There are third-party modules/CmdLets that create GZip. It is a straightforward process to access the CLI using PowerShell to create a GZip.
In support of creating a Gzip the following PowerShell functions were implemented:
- New-GZipArchive: function that creates the actual GZip file
- Close-Stream: helper function that handles closing/disposing the streams used.
The code is as follows:
function Close-Stream {
param
(
[Parameter(Mandatory=$false)]
[System.IO.Stream] $stream
)
if ($null -ne $stream) {
$stream.Close()
$stream.Dispose()
}
}
function New-GZipArchive {
param
(
[Parameter(Mandatory=$true)]
[string] $sourceFilePath,
[Parameter(Mandatory=$true)]
[string] $destinationFilePath,
[switch] $overwrite
)
[System.IO.FileStream] $sourceFileStream = $null
[System.IO.FileStream] $destinationFileStream = $null
[System.IO.Compression.GZipStream] $gzipStream
try {
if ($overwrite)
{
if (Test-Path `
-Path $destinationFilePath `
-PathType Leaf `
-ErrorAction:Stop) {
Remove-Item `
-Path $destinationFilePath`
-ErrorAction:Stop
}
}
[byte[]] $buffer = [System.Byte[]]::new([Math]::Pow(2, 20))
$sourceFileStream = [System.IO.FileStream]::new(
$sourceFilePath,
[System.IO.FileMode]::Open,
[System.IO.FileAccess]::Read,
[System.IO.FileShare]::Read)
$destinationFileStream = [System.IO.FileStream]::new(
$destinationFilePath,
[System.IO.FileMode]::CreateNew,
[System.IO.FileAccess]::Write,
[System.IO.FileShare]::None)
$gzipStream = [System.IO.Compression.GZipStream]::new(
$destinationFileStream,
[System.IO.Compression.CompressionMode]::Compress)
do {
[int] $bytesRead = $sourceFileStream.Read(
$buffer,
0,
$buffer.Length)
$gzipStream.Write($buffer, 0, $bytesRead)
} while($bytesRead -ne 0)
}
finally {
Close-Stream $sourceFileStream
Close-Stream $gzipStream
Close-Stream $destinationFileStream
}
}
