GZIP From JAVA to C# translate

Question

I am using Visual Studio 2019, I am communicating with a (publicly available government) service probably written in Java, and I have a "badly packed data" error. I get JAVA code from the developer that works.

Here is the Java code

ByteArrayOutputStream bos = new ByteArrayOutputStream();

 GZIPOutputStream gZIPOutputStream;

 try {

       gZIPOutputStream = new GZIPOutputStream(bos);

 gZIPOutputStream.write(Files.readAllBytes(Paths.get("/Projects/STS/eTW/eTW-1_SIGNED.xml")));

       gZIPOutputStream.finish();

 } catch (IOException e1) {

       // TODO Auto-generated catch block

       e1.printStackTrace();

 }

Code packs xml with gzip, I need to have it in C #

I'm trying this

using (var compressedStream = new MemoryStream())
{
GZip.Compress(new MemoryStream(raw), compressedStream, false);
CompressedsignedxmlDocument = compressedStream.ToArray();
}

Unfortunately, I keep getting incorrectly packed data all the time. How should this be written in C #?

Answer 1

byte[] raw = Encoding.UTF8.GetBytes(signedxmlDocument.InnerXml);

Unfortunately it doesn't help
API response

Result: OK
{
"eventId": null,
"referenceNumber": "f278c61c-da34-4169-be7d-d16c7dd24511",
"etwDocStatus": 402,
"changeEtwDocStatusTs": 1626950008000,
"description": "Wystąpił błąd podczas przetwarzania wysyłki.",<---- There was an error processing your shipment.
"details": "Nieprawidłowo skompresowana treść.", <---- Incorrectly compressed content.
"upo": null,
"timestamp": 1626950011000
}

This article says GZipStream has a bug, is that true?

https://gist.github.com/muhammad-naderi/ae58ba0564897c6126c59164269ed428

Answer 2

Unfortunately, in my case, the empty string is deciphered.

Answer 3

What is GZip in your C# code? There is no such class in .NET. In .NET you can use GZipStream.

What is raw? You need to be very careful working with MemoryStream as streams are positional. If you are reading a stream then you need to "rewind" it if you need to read it again, and it is supported by the stream. Additionally you are dealing with stream lifetimes and since the compressed stream owns the output stream before you can get the stream results you need to ensure everything was written.

Note also that if you're dealing with an XML file (and not XML data in memory) then you can more easily just work with file stream but I'll demo pulling the string from memory.

   //Test data  
   var xml = "your xml string";  
   var dataToCompress = Encoding.ASCII.GetBytes(xml);  
     
   //Compress it  
   byte[] compressedData;  
   using (var input = new MemoryStream(dataToCompress))  
   using (var output = new MemoryStream())  
   using (var gzip = new GZipStream(output, CompressionMode.Compress))  
   {  
       //Flush to ensure it is all written  
       input.CopyTo(gzip);  
       gzip.Flush();  
     
       //Rewind  
       output.Seek(0, SeekOrigin.Begin);  
       compressedData = output.ToArray();  
   };  
     
   //Decompress it  
   string uncompressedData;  
   using (var inputToRead = new MemoryStream(compressedData))  
   using (var gzipReader = new GZipStream(inputToRead, CompressionMode.Decompress))  
   using (var outputResult = new MemoryStream())  
   {  
       //Flush to ensure it is all written  
       gzipReader.CopyTo(outputResult);  
       gzipReader.Flush();  
     
       //Rewind  
       outputResult.Seek(0, SeekOrigin.Begin);  
     
       //Convert back to string  
       uncompressedData = Encoding.ASCII.GetString(outputResult.ToArray());  
   };  
     
   var areEqual = xml == uncompressedData;  

Answer 4

no my problem is not solved.

var areEqual = xml == uncompressedData;

Below is a screenshot

Net Framework 4.7.2

After further attempts, whatever I type in xml, I have the same result for compressedData, and uncompressedData is empty.

I have used code from this thread, will it be correct?
https://stackoverflow.com/questions/7343465/compression-decompression-string-with-c-sharp

Answer 5

Try this fix:

string xml = "your xml string";

// Compress it

var dataToCompress = Encoding.UTF8.GetBytes( xml );
byte[] compressedData;
using( var output = new MemoryStream( ) )
{
   using( var gzip = new GZipStream( output, CompressionMode.Compress ) )
   {
      gzip.Write( dataToCompress, 0, dataToCompress.Length );
   }
   compressedData = output.ToArray( );
}

// Decompress it

string uncompressedData;
using( var outputResult = new MemoryStream( ) )
{
   using( var inputToRead = new MemoryStream( compressedData ) )
   {
      using( var gzipReader = new GZipStream( inputToRead, CompressionMode.Decompress ) )
      {
         gzipReader.CopyTo( outputResult );
      }
   }
   uncompressedData = Encoding.UTF8.GetString( outputResult.GetBuffer( ), 0, (int)outputResult.Length );
}

bool areEqual = xml == uncompressedData;