Unzip files programmatically in .net

I am trying to programatically unzip a zipped file.

I have tried using the System.IO.Compression.GZipStream class in .NET, but when my app runs (actually a unit test) I get this exception:

System.IO.InvalidDataException: The magic number in GZip header is not correct. Make sure you are passing in a GZip stream..

I now realize that a .zip file is not the same as a .gz file, and that GZip is not the same as Zip.

However, since I'm able to extract the file by manually double clicking the zipped file and then clicking the "Extract all files"-button, I think there should be a way of doing that in code as well.

Therefore I've tried to use Process.Start() with the path to the zipped file as input. This causes my app to open a Window showing the contents in the zipped file. That's all fine, but the app will be installed on a server with none around to click the "Extract all files"-button.

So, how do I get my app to extract the files in the zipped files?

Or is there another way to do it? I prefer doing it in code, without downloading any third party libraries or apps; the security department ain't too fancy about that...

Solution 1:

With .NET 4.5 you can now unzip files using the .NET framework:

using System;
using System.IO;

namespace ConsoleApplication
{
  class Program
  {
    static void Main(string[] args)
    {
      string startPath = @"c:\example\start";
      string zipPath = @"c:\example\result.zip";
      string extractPath = @"c:\example\extract";

      System.IO.Compression.ZipFile.CreateFromDirectory(startPath, zipPath);
      System.IO.Compression.ZipFile.ExtractToDirectory(zipPath, extractPath);
    }
  }
}

The above code was taken directly from Microsoft's documentation: http://msdn.microsoft.com/en-us/library/ms404280(v=vs.110).aspx

ZipFile is contained in the assembly System.IO.Compression.FileSystem. (Thanks nateirvin...see comment below). You need to add a DLL reference to the framework assembly System.IO.Compression.FileSystem.dll

Solution 2:

For .Net 4.5+

It is not always desired to write the uncompressed file to disk. As an ASP.Net developer, I would have to fiddle with permissions to grant rights for my application to write to the filesystem. By working with streams in memory, I can sidestep all that and read the files directly:

using (ZipArchive archive = new ZipArchive(postedZipStream))
{
    foreach (ZipArchiveEntry entry in archive.Entries)
    {
         var stream = entry.Open();
         //Do awesome stream stuff!!
    }
}

Alternatively, you can still write the decompressed file out to disk by calling ExtractToFile():

using (ZipArchive archive = ZipFile.OpenRead(pathToZip))
{
    foreach (ZipArchiveEntry entry in archive.Entries)
    {
        entry.ExtractToFile(Path.Combine(destination, entry.FullName));
    }
} 

To use the ZipArchive class, you will need to add a reference to the System.IO.Compression namespace and to System.IO.Compression.FileSystem.

Solution 3:

We have used SharpZipLib successfully on many projects. I know it's a third party tool, but source code is included and could provide some insight if you chose to reinvent the wheel here.

Solution 4:

Free, and no external DLL files. Everything is in one CS file. One download is just the CS file, another download is a very easy to understand example. Just tried it today and I can't believe how simple the setup was. It worked on first try, no errors, no nothing.

https://github.com/jaime-olivares/zipstorer

Solution 5:

Use the DotNetZip library at http://www.codeplex.com/DotNetZip

class library and toolset for manipulating zip files. Use VB, C# or any .NET language to easily create, extract, or update zip files...

DotNetZip works on PCs with the full .NET Framework, and also runs on mobile devices that use the .NET Compact Framework. Create and read zip files in VB, C#, or any .NET language, or any scripting environment...

If all you want is a better DeflateStream or GZipStream class to replace the one that is built-into the .NET BCL, DotNetZip has that, too. DotNetZip's DeflateStream and GZipStream are available in a standalone assembly, based on a .NET port of Zlib. These streams support compression levels and deliver much better performance than the built-in classes. There is also a ZlibStream to complete the set (RFC 1950, 1951, 1952)...