Question

Using the DotNetZip Library (http://dotnetzip.codeplex.com/) is there a way to move files from one zip file into another without extracting that file to disk first? Maybe extract to a stream, then update into the other zip from that same stream?

The zip files are password protected and the data in these zip files are meant to stay that way due to their licenses. If I simply extract to disk first then update the other zip there is a chance where those files can be intercepted by the user.

Answer 1

Yes, you should be able to do something like;

var ms = new MemoryStream();

using (ZipFile zip = ZipFile.Read(sourceZipFile))
{
    zip.Extract("NameOfEntryInArchive.doc", ms);
}

ms.Seek(0);

using (ZipFile zip = new ZipFile())
{
    zip.AddEntry("NameOfEntryInArchive.doc", ms);
    zip.Save(zipToCreate);
}

(see it as pseudocode since I didn’t have a chance to compile)

Naturally you’ll have to add your decryption/encryption to that, but those calls are equally straight forward.