SharpZipLib

Code Reference / Zip Samples / Create a Zip with full control over content

This sample illustrates many aspects:

multiple entries
entry name correction
passwords and encryption options
Zip64 format issues.

While this example is purely disk files, the next following example shows how to use memory stream for input and output.

using System;
using System.IO;
using ICSharpCode.SharpZipLib.Core;
using ICSharpCode.SharpZipLib.Zip;

// Compresses the files in the nominated folder, and creates a zip file 
// on disk named as outPathname.
public void CreateSample(string outPathname, string password, string folderName) {

    using(FileStream fsOut = File.Create(outPathname))
    using(var zipStream = new ZipOutputStream(fsOut)) {

        //0-9, 9 being the highest level of compression
        zipStream.SetLevel(3); 

        // optional. Null is the same as not setting. Required if using AES.
        zipStream.Password = password;	

        // This setting will strip the leading part of the folder path in the entries, 
        // to make the entries relative to the starting folder.
        // To include the full path for each entry up to the drive root, assign to 0.
        int folderOffset = folderName.Length + (folderName.EndsWith("\\") ? 0 : 1);

        CompressFolder(folderName, zipStream, folderOffset);

    }

}

// Recursively compresses a folder structure
private void CompressFolder(string path, ZipOutputStream zipStream, int folderOffset) {

    var files = Directory.GetFiles(path);

    foreach (var filename in files) {

        var fi = new FileInfo(filename);

        // Make the name in zip based on the folder
        var entryName = filename.Substring(folderOffset);

        // Remove drive from name and fix slash direction
        entryName = ZipEntry.CleanName(entryName); 

        var newEntry = new ZipEntry(entryName);

        // Note the zip format stores 2 second granularity
        newEntry.DateTime = fi.LastWriteTime; 

        // Specifying the AESKeySize triggers AES encryption. 
        // Allowable values are 0 (off), 128 or 256.
        // A password on the ZipOutputStream is required if using AES.
        //   newEntry.AESKeySize = 256;

        // To permit the zip to be unpacked by built-in extractor in WinXP and Server2003,
        // WinZip 8, Java, and other older code, you need to do one of the following: 
        // Specify UseZip64.Off, or set the Size.
        // If the file may be bigger than 4GB, or you do not need WinXP built-in compatibility, 
        // you do not need either, but the zip will be in Zip64 format which
        // not all utilities can understand.
        //   zipStream.UseZip64 = UseZip64.Off;
        newEntry.Size = fi.Length;

        zipStream.PutNextEntry(newEntry);

        // Zip the file in buffered chunks
        // the "using" will close the stream even if an exception occurs
        var buffer = new byte[4096];
        using (FileStream fsInput = File.OpenRead(filename)) {
            StreamUtils.Copy(fsInput, zipStream, buffer);
        }
        zipStream.CloseEntry();
    }

    // Recursively call CompressFolder on all folders in path
    var folders = Directory.GetDirectories(path);
    foreach (var folder in folders) {
        CompressFolder(folder, zipStream, folderOffset);
    }
}

Imports System
Imports System.IO
Imports ICSharpCode.SharpZipLib.Core
Imports ICSharpCode.SharpZipLib.Zip

' Compresses the files in the nominated folder, and creates a zip file on disk named as outPathname.
'
Public Sub CreateSample(outPathname As String, password As String, folderName As String)

    Using fsOut As FileStream = File.Create(outPathname)
        Using zipStream As New ZipOutputStream(fsOut)

            '0-9, 9 being the highest level of compression
            zipStream.SetLevel(3)

            ' optional. Null is the same as not setting.
            zipStream.Password = password	

            ' This setting will strip the leading part of the folder path in the entries, 
            ' to make the entries relative to the starting folder.
            ' To include the full path for each entry up to the drive root, assign to 0.
            Dim folderOffset As Integer = folderName.Length + (If(folderName.EndsWith("\"), 0, 1))

            CompressFolder(folderName, zipStream, folderOffset)

        End Using
    End Using
End Sub

' Recurses down the folder structure
'
Private Sub CompressFolder(path As String, zipStream As ZipOutputStream, folderOffset As Integer)

    Dim files As String() = Directory.GetFiles(path)

    For Each filename As String In files

        Dim fi As New FileInfo(filename)

        ' Make the name in zip based on the folder
        Dim entryName As String = filename.Substring(folderOffset)
        
        ' Remove drive from name and fix slash direction
        entryName = ZipEntry.CleanName(entryName)
        Dim newEntry As New ZipEntry(entryName)
        
        ' Note the zip format stores 2 second granularity
        newEntry.DateTime = fi.LastWriteTime

        ' Specifying the AESKeySize triggers AES encryption. Allowable values are 0 (off), 128 or 256.
        '   newEntry.AESKeySize = 256;

        ' To permit the zip to be unpacked by built-in extractor in WinXP and Server2003, WinZip 8, Java, and other older code,
        ' you need to do one of the following: Specify UseZip64.Off, or set the Size.
        ' If the file may be bigger than 4GB, or you do not need WinXP built-in compatibility, you do not need either,
        ' but the zip will be in Zip64 format which not all utilities can understand.
        '   zipStream.UseZip64 = UseZip64.Off;
        newEntry.Size = fi.Length

        zipStream.PutNextEntry(newEntry)

        ' Zip the file in buffered chunks
        ' the "using" will close the stream even if an exception occurs
        Dim buffer As Byte() = New Byte(4095) {}
        Using streamReader As FileStream = File.OpenRead(filename)
            StreamUtils.Copy(streamReader, zipStream, buffer)
        End Using
        zipStream.CloseEntry()
    Next
    Dim folders As String() = Directory.GetDirectories(path)
    For Each folder As String In folders
        CompressFolder(folder, zipStream, folderOffset)
    Next
End Sub

Information

Code Examples