[MSH] Displaying Zip File contents Let's have some fun with zip files.

I have searched through MSDN document on whether .NET library but could not finddd
any C#/VB.net library that deals with Zip file content.

I have been googling around the web but found a useful J# library for dealing with
zip files easily. The name of J# library is called "VJSLIB.DLL".

Here is the step on how to get a Zip file content

1. Open "java.io.FileInputStream" for a zip file


2. Pipe File Input stream object to "java.io.ZipInputStream"


3. While there exists a content in a zip input stream, get a content of type "ZipEntry"


4. Close "ZipInputStream" first and then "FileInputStream"

# Author: DBMwS
# Date: 02/27/2006 @ 04:13 PM EST
# Description: Retrieve a Zip file's content
#  (either display only files inside the zip file or return ZipEntry object)
# Note: This function requires J# Library, "vjslib"
# Usage: get-ZipContent file_name [[System.Bool] -toString]
# Reference: http://codeproject.com/csharp/VmEasyZipUnZip.asp
# Params
#  1) $zipFileName: Path of zip file
# 2) $toString: return name of zip content, otherwise return ZipEntry
function Get-ZipContent {
 param($zipFileName = $(throw "Enter Zip File Name"), [bool]$toString = $true)

 # Load J# library
 # used "out-null" instead of "[void]" since "out-null" would not display
 # loaded assembly even if there was an exception thrown
 [System.Reflection.Assembly]::LoadWithPartialName("vjslib") | out-null

 # 1) Open "java.io.FileInputStream" for a zip file
 $fis = new-object java.io.FileInputStream($zipFileName)
 # 2) Pipe File Input stream object to "java.io.ZipInputStream"
 $zis = new-object java.util.zip.ZipInputStream($fis)

 # 3) While there exists a content in a zip input stream, get a content of type "ZipEntry"
 while (($ze = $zis.getNextEntry()) -ne $null) {
  if ($toString) {
   # Pass string value to pipe
   Write-Object $ze.ToString()
  } else {
   # Pass actualy ZipEntry object to pipe
   $ze
  }
 }

 # 4) Close "ZipInputStream" first and then "FileInputStream"
 $zis.close()
 $fis.close()

 trap {
  if ($zis -ne $null) { $zis.close() }
  if ($fis -ne $null) { $fis.close() }
  break
 }
}

It is still not complete since, it does not list a zip file inside a given zip file name(no recursive listing)
But I have left that part out on purpose since "get-ZipContent" can be called recursively in a while loop in another function.

Here is how one can utilize "Get-ZipContent"

MSH>ls | where {!$_.MshIsContainer -and $_.name -like "*.zip"} | foreach { get-zipcontent $_.fullname } | where { $_ -like "*.jpg" }

In above code snippet, i have used "where {!$_.MshIsContainer -and $_.name -like "*.zip"}" to filter out directories and select files with only "*.zip" extension
(Well, if you don't filter out files that way, get-ZipContent would fail half way when a directory or a non-zip file has been passed to it)

Well, I will be talking about how to actually "extract" the contents in the next blog.

EDIT: Tested under both Monad v3.0 & v3.1 ;) Refer to /\/\o\/\/'s blog on Beta v3.1 release here



Reference: Zip and Unzip from a C# program using J# runtime by Valeri

Tags : Monad msh  ¶ 4:42 PM