System.IO.Compression.ZipFile .NET 4.5 output zip in not suitable for Linux/Mac/Java

Question

While using .NET System.IO.Compression.ZipFile.CreateFromDirectory class the outcome zip is badly extracted on system with forward-slash directory separator.

Answer 1

The correct work around for this issue is as follows

class MyEncoder : UTF8Encoding
{
    public MyEncoder() : base(true)
    {

    }
    public override byte[] GetBytes(string s)
    {
        s = s.Replace("\\", "/");
        return base.GetBytes(s);
   }
}

NOTE: This is slightly different from a previous answer.

The key difference is in the : base(true)

This is important or the .NET ZipArchive class will NOT recognize the encoder as a UTF-8 encoder and will NOT mark the correct general purpose bit, and thus extracting the resulting zip file with any other zip program will assume the zip entry name is in a non-unicode encoding which might result in a mangled filename.

The reason is due to a internal call in .NET to check if the custom encoder is .equals(Encoding.UTF8) which isn't true unless true is passed for the encoderShouldEmitUTF8Identifier like Encoding.UTF8