SharpZipLib with MemoryStream

Question

I have been developing a web application with asp.net and I have smoe question about SharZipLib. I have a file called Template.odt (from Open Office) and this file is a compacted file (like docx) and we have some other files inside it (manifiest, xml, images etc). I need to open this file change a file called content.xml and styles.xml and save in another .odt file and give to my client. But I'm not sure if we can use temporary files, so I was thinking how to do this using MemoryStream.

Look what I got:

protected byte[ GetReport() {
    Stream inputStream = File.OpenRead(Server.MapPath("~/Odt/Template.odt"));
    var zipInputStream = new ZipInputStream(inputStream);
    var outputStream = new MemoryStream();
    var zipOutputStream = new ZipOutputStream(outputStream);
    ZipEntry entry = zipInputStream.GetNextEntry();
    while (entry != null) {     

        if (entry.Name == "content.xml") 
            // how change the content ?
        else if (entry.Name == "styles.xml") 
            // how change the content ?

        // how to add it or create folders in the output ?
        zipOutputStream.Write( ??? );

        entry = zipInputStream.GetNextEntry();
    }
    zipOutputStream.Flush();
    return outputStream.ToArray();
}

I'm not sure if it's right but I think it's on the way.

I try to take ExtraData from ZipEntry instance but I got it null, is it normal ?

Can someone help me?

Thank you

Answer 1

An example of how you can update ZIP files in memory can be found here: http://wiki.sharpdevelop.net/SharpZipLib_Updating.ashx#Updating_a_zip_file_in_memory_1

In your case, you probably have to load content.xml into a XmlDocument or XDocument to modify it - but that depends on what you are trying to change exactly.

As a sidemark: when using streams, make sure you are disposing of them. The easiest way is to wrap the operation in using statement:

   using(var inputStream = File.OpenRead(Server.MapPath("~/Odt/Template.odt")))
   {
      // ...
   }

More information on that: http://www.codeproject.com/Articles/6564/Understanding-the-using-statement-in-C