Unzipping a Stream in C# - c#

I'm working in C#, and I'm downloading for the internet a zip file with one XML file in it. and I wish to load this XML file. This is what I have so far:
byte[] data;
WebClient webClient = new WebClient();
try {
data = webClient.DownloadData(downloadUrl);
}
catch (Exception ex) {
Console.WriteLine("Error in DownloadData (Ex:{0})", ex.Message);
throw;
}
if (data == null) {
Console.WriteLine("Bulk data is null");
throw new Exception("Bulk data is null");
}
//Create the stream
MemoryStream stream = new MemoryStream(data);
XmlDocument document = new XmlDocument();
//Gzip
GZipStream gzipStream = new GZipStream(stream, CompressionMode.Decompress);
//Load report straight from the gzip stream
try {
document.Load(gzipStream);
}
catch (Exception ex) {
Console.WriteLine("Error in Load (Ex:{0})", ex.Message);
throw;
}
in document.Load I'm always getting the following exception:
The magic number in GZip header is not correct. Make sure you are passing in a GZip stream.
What I'm doing wrong?

Apparently SharpZipLib is now unmaintained and you probably want to avoid it:
https://stackoverflow.com/a/593030
In .NET 4.5 there is now built in support for zip files, so for your example it would be:
var data = new WebClient().DownloadData(downloadUrl);
//Create the stream
var stream = new MemoryStream(data);
var document = new XmlDocument();
//zip
var zipArchive = new ZipArchive(stream);
//Load report straight from the zip stream
document.Load(zipArchive.Entries[0].Open());

If you have a byte array that contains a zip archive with a single file, you can use the ZipArchive class to get an unzipped byte array with the file's data.
ZipArchive is contained in .NET 4.5, in the assembly System.IO.Compression.FileSystem (you need to reference it explicitly).
The following function, adapted from this answer, works for me:
public static byte[] UnzipSingleEntry(byte[] zipped)
{
using (var memoryStream = new MemoryStream(zipped))
{
using (var archive = new ZipArchive(memoryStream))
{
foreach (ZipArchiveEntry entry in archive.Entries)
{
using (var entryStream = entry.Open())
{
using (var reader = new BinaryReader(entryStream))
{
return reader.ReadBytes((int)entry.Length);
}
}
}
}
}
return null; // To quiet my compiler
}

I am using SharpZipLib and it's working great !
Below is a function that encapsulate the library
public static void Compress(FileInfo sourceFile, string destinationFileName,string destinationTempFileName)
{
Crc32 crc = new Crc32();
string zipFile = Path.Combine(sourceFile.Directory.FullName, destinationTempFileName);
zipFile = Path.ChangeExtension(zipFile, ZIP_EXTENSION);
using (FileStream fs = File.Create(zipFile))
{
using (ZipOutputStream zOut = new ZipOutputStream(fs))
{
zOut.SetLevel(9);
ZipEntry entry = new ZipEntry(ZipEntry.CleanName(destinationFileName));
entry.DateTime = DateTime.Now;
entry.ZipFileIndex = 1;
entry.Size = sourceFile.Length;
using (FileStream sourceStream = sourceFile.OpenRead())
{
crc.Reset();
long len = sourceFile.Length;
byte[] buffer = new byte[bufferSize];
while (len > 0)
{
int readSoFar = sourceStream.Read(buffer, 0, buffer.Length);
crc.Update(buffer, 0, readSoFar);
len -= readSoFar;
}
entry.Crc = crc.Value;
zOut.PutNextEntry(entry);
len = sourceStream.Length;
sourceStream.Seek(0, SeekOrigin.Begin);
while (len > 0)
{
int readSoFar = sourceStream.Read(buffer, 0, buffer.Length);
zOut.Write(buffer, 0, readSoFar);
len -= readSoFar;
}
}
zOut.Finish();
zOut.Close();
}
fs.Close();
}
}

As the others have mentioned GZip and Zip are not the same so you might need to use a zip library. I use a library called: DotNetZip - available from the below site:
http://dotnetzip.codeplex.com/

From GZipStream Class description:
Compressed GZipStream objects written to a file with an extension of .gz can be decompressed using many common compression tools; however, this class does not inherently provide functionality for adding files to or extracting files from .zip archives
So unless you control server-side files, I'd suggest looking for specific zip-targeted library (SharpZipLib for example).

Related

Using a generic stream to create a zipped file with SharpCompress

Since System.IO.Compression seems to be out of reach for now if I want to use both dotnet core + net461, I've tried with SharpCompress.
The "read zip" part was easy, but I am having trouble finding out how to write to a zip stream.
The wiki of the project is a bit outdated. This is the only example that I've found that applies to writing to streams. I've tried to follow it and adapt it to my needs, but I am stuck at the exception it throws:
using Microsoft.VisualStudio.TestTools.UnitTesting;
using SharpCompress.Common;
using SharpCompress.Compressors.Deflate;
using SharpCompress.Writers;
using System;
using System.IO;
namespace DbManager.DjdbCore.Tests
{
[TestClass]
public class ZipTests
{
public ZipTests()
{
Directory.SetCurrentDirectory(AppContext.BaseDirectory);
}
[TestMethod]
public void Test()
{
var zip = File.OpenWrite(#"..\..\..\..\..\test-resources\zip_file_test.zip");
var writerOptions = new WriterOptions(CompressionType.Deflate);
var zipWriter = WriterFactory.Open(zip, ArchiveType.Zip, writerOptions);
var memoryStream = new MemoryStream();
var binaryWriter = new BinaryWriter(memoryStream);
binaryWriter.Write("Test string inside binary file - text to fill it up: qoiwjqefñlawijfñlaskdjfioqwjefñalskvndñaskvnqo`wiefowainvñaslkfjnwpowiqjfeopwiqjnfjñlaskdjfñlasdfjiowiqjefñaslkdjfñalskjfpqwoiefjqw");
var deflateStream = new DeflateStream(memoryStream, SharpCompress.Compressors.CompressionMode.Compress);
deflateStream.Write(memoryStream.ToArray(), 0, Convert.ToInt32(memoryStream.Length));
// EXCEPTION: SharpCompress.Compressors.Deflate.ZlibException: 'Cannot Read after Writing.'
// Source code: if (_streamMode != StreamMode.Reader) { throw new ZlibException("Cannot Read after Writing."); }
zipWriter.Write("test_file_inside_zip.bin", deflateStream, DateTime.Now);
zip.Flush();
zipWriter.Dispose();
zip.Dispose();
}
}
}
In case it helps, this is what I used (and it worked, but only in dotnet core) using the library System.IO.Compression:
private void WriteAsZipBinary()
{
//Open the zip file if it exists, else create a new one
var zip = ZipPackage.Open(this.FileFullPath, FileMode.OpenOrCreate, FileAccess.ReadWrite);
var zipStream = ZipManager.GetZipWriteStream(zip, nameOfFileInsideZip);
var memoryStream = new MemoryStream();
var binaryWriter = new BinaryWriter(memoryStream);
// Here is where strings etc are written to the binary file:
WriteStuffInBinaryStream(ref binaryWriter);
//Read all of the bytes from the file to add to the zip file
byte[] bites = new byte[Convert.ToInt32(memoryStream.Length - 1) + 1];
memoryStream.Position = 0;
memoryStream.Read(bites, 0, Convert.ToInt32(memoryStream.Length));
binaryWriter.Dispose();
binaryWriter = null;
memoryStream.Dispose();
memoryStream = null;
zipStream.Position = 0;
zipStream.Write(bites, 0, bites.Length);
zip.Close();
}
public static Stream GetZipWriteStream(Package zip, string renamedFileName)
{
//Replace spaces with an underscore (_)
string uriFileName = renamedFileName.Replace(" ", "_");
//A Uri always starts with a forward slash "/"
string zipUri = string.Concat("/", Path.GetFileName(uriFileName));
Uri partUri = new Uri(zipUri, UriKind.Relative);
string contentType = "Zip"; // System.Net.Mime.MediaTypeNames.Application.Zip;
//The PackagePart contains the information:
// Where to extract the file when it's extracted (partUri)
// The type of content stream (MIME type): (contentType)
// The type of compression: (CompressionOption.Normal)
PackagePart pkgPart = zip.CreatePart(partUri, contentType, CompressionOption.Normal);
//Compress and write the bytes to the zip file
return pkgPart.GetStream();
}
I'll post here the answer on github from #adamhathcock (the owner of the project):
[TestMethod]
public void Test()
{
var writerOptions = new WriterOptions(CompressionType.Deflate);
using(var zip = File.OpenWrite(#"..\..\..\..\..\test-resources\zip_file_test.zip"))
using(var zipWriter = WriterFactory.Open(zip, ArchiveType.Zip, writerOptions))
{
var memoryStream = new MemoryStream();
var binaryWriter = new BinaryWriter(memoryStream);
binaryWriter.Write("Test string inside binary file - text to fill it up: qoiwjqefñlawijfñlaskdjfioqwjefñalskvndñaskvnqo`wiefowainvñaslkfjnwpowiqjfeopwiqjnfjñlaskdjfñlasdfjiowiqjefñaslkdjfñalskjfpqwoiefjqw");
memoryStream.Position = 0;
zipWriter.Write("test_file_inside_zip.bin", memoryStream, DateTime.Now);
}
}
2 things:
You forgot to reset the MemoryStream after writing to it so it can be read.
You don't need to manually use the DeflateStream. You've told the ZipWriter what compression to use. If it worked, you would have double compressed the bytes which would be garbage really.

Load a file from Asset using Xamarin android

I want to load a file from the Asset, I found the solution but with Java. How can I convert following Java code to c#.
public String loadKMLFromAsset() {
String kmlData = null;
try {
InputStream is = getAssets().open("yourKMLFile");
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
kmlData = new String(buffer, "UTF-8");
} catch (IOException ex) {
ex.printStackTrace();
return null;
}
return kmlData;
}
Use AssetManager
// Read the contents of our asset
string content;
AssetManager assets = this.Assets;
using (StreamReader sr = new StreamReader (assets.Open ("read_asset.txt")))
{
content = sr.ReadToEnd ();
}
Use BinaryReader instead of streamReader, if u are working with files such as db, kml, shapefiles,, video formats, etc. StreamReader reads only strings or just plain text, so when reading binary file some of the content may be skipped, since streamreader doesnt read byte by byte
This code writes the asset file to a file in your mobile file system:
if (!System.IO.File.Exists("yourKMLFile_mobile"))
{
var s = Resources.OpenRawResource(Resource.Raw.yourKMLFile);
FileStream writeStream = new FileStream("yourKMLFile_mobile", FileMode.OpenOrCreate, FileAccess.Write);
ReadWriteStream(s, writeStream);
}

GZipStream complains magic number in header is not correct

I'm attempting to use National Weather Service (U.S.) data, but something has changed recently and the GZip file no longer opens.
.NET 4.5 complains that...
Message=The magic number in GZip header is not correct. Make sure you are passing in a GZip stream.
Source=System
StackTrace:
at System.IO.Compression.GZipDecoder.ReadHeader(InputBuffer input)
at System.IO.Compression.Inflater.Decode()
at System.IO.Compression.Inflater.Inflate(Byte[] bytes, Int32 offset, Int32 length)
at System.IO.Compression.DeflateStream.Read(Byte[] array, Int32 offset, Int32 count)
I don't understand what has changed, but this is becoming a real show-stopper. Can anyone with GZip format experience tell me what has changed to make this stop working?
A file that works:
http://www.srh.noaa.gov/ridge2/Precip/qpehourlyshape/2015/201504/20150404/nws_precip_2015040420.tar.gz
A file that doesn't work:
http://www.srh.noaa.gov/ridge2/Precip/qpehourlyshape/2015/201505/20150505/nws_precip_2015050505.tar.gz
Update with sample code
const string url = "http://www.srh.noaa.gov/ridge2/Precip/qpehourlyshape/2015/201505/20150505/nws_precip_2015050505.tar.gz";
string appPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
string downloadPath = Path.Combine(appPath, Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), "nws_precip_2015050505.tar.gz");
using (var wc = new WebClient())
{
wc.DownloadFile(url, downloadPath);
}
string extractDirPath = Path.Combine(appPath, "Extracted");
if (!Directory.Exists(extractDirPath))
{
Directory.CreateDirectory(extractDirPath);
}
string extractFilePath = Path.Combine(extractDirPath, "nws_precip_2015050505.tar");
using (var fsIn = new FileStream(downloadPath, FileMode.Open, FileAccess.Read))
using (var fsOut = new FileStream(extractFilePath, FileMode.Create, FileAccess.Write))
using (var gz = new GZipStream(fsIn, CompressionMode.Decompress, true))
{
gz.CopyTo(fsOut);
}
It appears that this service SOMETIMES returns tar format files disguised as .tar.gz. This is very confusing, but if you check that the first two bytes are 0x1F and 0x8B, you can detect if the file is a GZip by checking its magic numbers manually.
using (FileStream fs = new FileStream(downloadPath, FileMode.Open, FileAccess.Read))
{
byte[] buffer = new byte[2];
fs.Read(buffer, 0, buffer.Length);
if (buffer[0] == 0x1F
&& buffer[1] == 0x8B)
{
// It's probably a GZip file
}
else
{
// It's probably not a GZip file
}
}
[Resolved] GZipStream complains magic number in header is not correct
//Exception magic number tar.gz file
Migcal error cause
File is not compress into tar.gz properly
File size is too big , above 1+GB
Solution over it
use .net framework 4.5.1 to over the this exception //OR//
manupulate the exsiting solution without change .net framework.
Please follow the step for implementation.
Remane abc.tar.gz as abc (remove extension).
pass this file and directly name to compress function
*public static void Compress(DirectoryInfo directorySelected, string directoryPath)
{
foreach (FileInfo fileToCompress in directorySelected.GetFiles())
{
using (FileStream originalFileStream = fileToCompress.OpenRead())
{
if ((File.GetAttributes(fileToCompress.FullName) &
FileAttributes.Hidden) != FileAttributes.Hidden & fileToCompress.Extension != ".tar.gz")
{
using (FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".tar.gz"))
{
using (System.IO.Compression.GZipStream compressionStream = new System.IO.Compression.GZipStream(compressedFileStream,
System.IO.Compression.CompressionMode.Compress))
{
originalFileStream.CopyTo(compressionStream);
}
}
FileInfo info = new FileInfo(directoryPath + "\\" + fileToCompress.Name + ".tar.gz");
}
}
}
}
3. implement this code in following exception handler try catch block
try
{
TarGzFilePath=#"c:\temp\abc.tar.gz";
FileStream streams = File.OpenRead(TarGzFilePath);
string FileName=string.Empty;
GZipInputStream tarGz = new GZipInputStream(streams);
TarInputStream tar = new TarInputStream(tarGz);
// exception will occured in below lines should apply try catch
TarEntry ze;
try
{
ze = tar.GetNextEntry();// exception occured here "magical number"
}
catch (Exception extra)
{
tar.Close();
tarGz.Close();
streams.Close();
//please close all above , other wise it will come with exception "tihs process use by another process"
//rename your file *for better accuracy you can copy file to other location
File.Move(#"c:\temp\abc.tar.gz", #"c:\temp\abc"); // rename file
DirectoryInfo directorySelected = new DirectoryInfo(Path.GetDirectoryName(#"c:\temp\abc"));
Compress(directorySelected, directoryPath); // directorySelected=c:\temp\abc , directoryPath=c:\temp\abc.tar.gz // process in step 2 function
streams = File.OpenRead(TarGzFilePath);
tarGz = new GZipInputStream(streams);
tar = new TarInputStream(tarGz);
ze = tar.GetNextEntry();
}
// do anything with extraction with your code
}
catch (exception ex)
{
tar.Close();
tarGz.Close();
streams.Close();
}

Create new FileStream out of a byte array

I am attempting to create a new FileStream object from a byte array. I'm sure that made no sense at all so I will try to explain in further detail below.
Tasks I am completing:
1) Reading the source file which was previously compressed
2) Decompressing the data using GZipStream
3) copying the decompressed data into a byte array.
What I would like to change:
1) I would like to be able to use File.ReadAllBytes to read the decompressed data.
2) I would then like to create a new filestream object usingg this byte array.
In short, I want to do this entire operating using byte arrays. One of the parameters for GZipStream is a stream of some sort, so I figured I was stuck using a filestream. But, if some method exists where I can create a new instance of a FileStream from a byte array - then I should be fine.
Here is what I have so far:
FolderBrowserDialog fbd = new FolderBrowserDialog(); // Shows a browser dialog
fbd.ShowDialog();
// Path to directory of files to compress and decompress.
string dirpath = fbd.SelectedPath;
DirectoryInfo di = new DirectoryInfo(dirpath);
foreach (FileInfo fi in di.GetFiles())
{
zip.Program.Decompress(fi);
}
// Get the stream of the source file.
using (FileStream inFile = fi.OpenRead())
{
//Create the decompressed file.
string outfile = #"C:\Decompressed.exe";
{
using (GZipStream Decompress = new GZipStream(inFile,
CompressionMode.Decompress))
{
byte[] b = new byte[blen.Length];
Decompress.Read(b,0,b.Length);
File.WriteAllBytes(outfile, b);
}
}
}
Thanks for any help!
Regards,
Evan
It sounds like you need to use a MemoryStream.
Since you don't know how many bytes you'll be reading from the GZipStream, you can't really allocate an array for it. You need to read it all into a byte array and then use a MemoryStream to decompress.
const int BufferSize = 65536;
byte[] compressedBytes = File.ReadAllBytes("compressedFilename");
// create memory stream
using (var mstrm = new MemoryStream(compressedBytes))
{
using(var inStream = new GzipStream(mstrm, CompressionMode.Decompress))
{
using (var outStream = File.Create("outputfilename"))
{
var buffer = new byte[BufferSize];
int bytesRead;
while ((bytesRead = inStream.Read(buffer, 0, BufferSize)) != 0)
{
outStream.Write(buffer, 0, bytesRead);
}
}
}
}
Here is what I ended up doing. I realize that I did not give sufficient information in my question - and I apologize for that - but I do know the size of the file I need to decompress as I am using it earlier in my program. This buffer is referred to as "blen".
string fi = #"C:\Path To Compressed File";
// Get the stream of the source file.
// using (FileStream inFile = fi.OpenRead())
using (MemoryStream infile1 = new MemoryStream(File.ReadAllBytes(fi)))
{
//Create the decompressed file.
string outfile = #"C:\Decompressed.exe";
{
using (GZipStream Decompress = new GZipStream(infile1,
CompressionMode.Decompress))
{
byte[] b = new byte[blen.Length];
Decompress.Read(b,0,b.Length);
File.WriteAllBytes(outfile, b);
}
}
}

.Net Zip Up files

Whats the best way to zip up files using C#? Ideally I want to be able to seperate files into a single archive.
You can use DotNetZip to archieve this. It´s free to use in any application.
Here´s some sample code:
try
{
// for easy disposal
using (ZipFile zip = new ZipFile())
{
// add this map file into the "images" directory in the zip archive
zip.AddFile("c:\\images\\personal\\7440-N49th.png", "images");
// add the report into a different directory in the archive
zip.AddFile("c:\\Reports\\2008-Regional-Sales-Report.pdf", "files");
zip.AddFile("ReadMe.txt");
zip.Save("MyZipFile.zip");
}
}
catch (System.Exception ex1)
{
System.Console.Error.WriteLine("exception: " + ex1);
}
This is now built into the framework if you have version 4.5+
Otherwise, use Ionic.
Namespace is System.IO.Packaging.ZIPPackage.
See http://visualstudiomagazine.com/articles/2012/05/21/net-framework-gets-zip.aspx for a story.
Have you looked at SharpZipLib?
I believe you can build zip files with classes in the System.IO.Packaging namespace - but every time I've tried to look into it, I've found it rather confusing...
Take a look at this library:
http://www.icsharpcode.net/OpenSource/SharpZipLib/
It is pretty comprehensive, it deals with many formats, is open-source, and you can use in closed-source commercial applications.
It is very simple to use:
byte[] data1 = new byte[...];
byte[] data2 = new byte[...];
/*...*/
var path = #"c:\test.zip";
var zip = new ZipOutputStream(new FileStream(path, FileMode.Create))
{
IsStreamOwner = true
}
zip.PutNextEntry("File1.txt");
zip.Write(data1, 0, data1.Length);
zip.PutNextEntry("File2.txt");
zip.Write(data2, 0, data2.Length);
zip.Close();
zip.Dispose();
There are a few librarys around - the most popular of which are DotNetZip and SharpZipLib.
Hi i created two methods with the ShapLib library (you can download it here http://www.icsharpcode.net/opensource/sharpziplib/) that would like to share, they are very easy to use just pass source and target path (fullpath including folder/file and extension). Hope it help you!
//ALLYOURNAMESPACESHERE
using ...
//SHARPLIB
using ICSharpCode.SharpZipLib.Zip;
using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
public static class FileUtils
{
/// <summary>
///
/// </summary>
/// <param name="sourcePath"></param>
/// <param name="targetPath"></param>
public static void ZipFile(string sourcePath, string targetPath)
{
string tempZipFilePath = targetPath;
using (FileStream tempFileStream = File.Create(tempZipFilePath, 1024))
{
using (ZipOutputStream zipOutput = new ZipOutputStream(tempFileStream))
{
// Zip with highest compression.
zipOutput.SetLevel(9);
DirectoryInfo directory = new DirectoryInfo(sourcePath);
foreach (System.IO.FileInfo file in directory.GetFiles())
{
// Get local path and create stream to it.
String localFilename = file.FullName;
//ignore directories or folders
//ignore Thumbs.db file since this probably will throw an exception
//another process could be using it. e.g: Explorer.exe windows process
if (!file.Name.Contains("Thumbs") && !Directory.Exists(localFilename))
{
using (FileStream fileStream = new FileStream(localFilename, FileMode.Open, FileAccess.Read, FileShare.Read))
{
// Read full stream to in-memory buffer.
byte[] buffer = new byte[fileStream.Length];
fileStream.Read(buffer, 0, buffer.Length);
// Create a new entry for the current file.
ZipEntry entry = new ZipEntry(file.Name);
entry.DateTime = DateTime.Now;
// set Size and the crc, because the information
// about the size and crc should be stored in the header
// if it is not set it is automatically written in the footer.
// (in this case size == crc == -1 in the header)
// Some ZIP programs have problems with zip files that don't store
// the size and crc in the header.
entry.Size = fileStream.Length;
fileStream.Close();
// Update entry and write to zip stream.
zipOutput.PutNextEntry(entry);
zipOutput.Write(buffer, 0, buffer.Length);
// Get rid of the buffer, because this
// is a huge impact on the memory usage.
buffer = null;
}
}
}
// Finalize the zip output.
zipOutput.Finish();
// Flushes the create and close.
zipOutput.Flush();
zipOutput.Close();
}
}
}
public static void unZipFile(string sourcePath, string targetPath)
{
if (!Directory.Exists(targetPath))
Directory.CreateDirectory(targetPath);
using (ZipInputStream s = new ZipInputStream(File.OpenRead(sourcePath)))
{
ZipEntry theEntry;
while ((theEntry = s.GetNextEntry()) != null)
{
if (theEntry.Name != String.Empty)
{
using (FileStream streamWriter = File.Create(targetPath + "\\" + theEntry.Name))
{
int size = 2048;
byte[] data = new byte[2048];
while (true)
{
size = s.Read(data, 0, data.Length);
if (size > 0)
{
streamWriter.Write(data, 0, size);
}
else
{
break;
}
}
}
}
}
}
}
}

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