I am working on some AES encryption in C#. I have a similar decryption method which functions flawlessly, however, no matter what I try I cannot read the encrypted contents of the MemoryStream
I have tried a few different ways of reading,
ms.Position = 0;
return new StreamReader(ms, Encoding.ASCII).ReadToEnd()
OR
using (StreamReader sr = new StreamReader(cs)) {
return sr.ReadToEnd();
}
OR
byte[] enc = ms.ToArray();
string ret=null;
foreach (byte b in enc) {
ret += b.ToString();
}
Here's the snippet from the code.
using (AesManaged aesMan = new AesManaged()) {
if (keystr.Length == aesSize/8)
{
//Its a valid key
aesMan.KeySize = aesSize;
aesMan.Key = Encoding.UTF8.GetBytes(keystr);
aesMan.IV = Encoding.UTF8.GetBytes(ivstr);
ICryptoTransform encryptor aesMan.CreateEncryptor(aesMan.Key, aesMan.IV);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
{
using (StreamWriter sw = new StreamWriter(cs))
{
sw.Write(inpstr);
using (StreamReader sr = new StreamReader(ms)) {
return sr.ReadToEnd();
}
}
}
I get various errors, such as the stream is not readable, or that it cannot read a closed stream, as well as a blank string being returned.
Has anyone got any ideas? I'm at a loss
Most of those stream functions like StreamReader, StreamWriter, etc., close the underlying stream when you Dispose() them. Try not disposing them until you are done, or using the constructors that allow you to chose not to close the underlying stream. In rare cases, I've had to implement a dummy wrapper around a stream to prevent closing the underlying stream
My end goal is to use protobuf-net and GZipStream in an attempt to compress a List<MyCustomType> object to store in a varbinary(max) field in SQL Server. I'm working on unit tests to understand how everything works and fits together.
Target .NET framework is 3.5.
My current process is:
Serialize the data with protobuf-net (good).
Compress the serialized data from #1 with GZipStream (good).
Convert the compressed data to a base64 string (good).
At this point, the value from step #3 will be stored in a varbinary(max) field. I have no control over this. The steps resume with needing to take a base64 string and deserialize it to a concrete type.
Convert a base 64 string to a byte[] (good).
Decompress the data with GZipStream (good).
Deserialize the data with protobuf-net (bad).
Can someone assist with why the call to Serializer.Deserialize<string> returns null? I'm stuck on this one and hopefully a fresh set of eyes will help.
FWIW, I tried another version of this using List<T> where T is a custom class I created and I Deserialize<> still returns null.
FWIW 2, data.txt is a 4MB plaintext file residing on my C:.
[Test]
public void ForStackOverflow()
{
string data = "hi, my name is...";
//string data = File.ReadAllText(#"C:\Temp\data.txt");
string serializedBase64;
using (MemoryStream protobuf = new MemoryStream())
{
Serializer.Serialize(protobuf, data);
using (MemoryStream compressed = new MemoryStream())
{
using (GZipStream gzip = new GZipStream(compressed, CompressionMode.Compress))
{
byte[] s = protobuf.ToArray();
gzip.Write(s, 0, s.Length);
gzip.Close();
}
serializedBase64 = Convert.ToBase64String(compressed.ToArray());
}
}
byte[] base64byteArray = Convert.FromBase64String(serializedBase64);
using (MemoryStream base64Stream = new MemoryStream(base64byteArray))
{
using (GZipStream gzip = new GZipStream(base64Stream, CompressionMode.Decompress))
{
using (MemoryStream plainText = new MemoryStream())
{
byte[] buffer = new byte[4096];
int read;
while ((read = gzip.Read(buffer, 0, buffer.Length)) > 0)
{
plainText.Write(buffer, 0, read);
}
// why does this call to Deserialize return null?
string deserialized = Serializer.Deserialize<string>(plainText);
Assert.IsNotNull(deserialized);
Assert.AreEqual(data, deserialized);
}
}
}
}
Because you didn't rewind plainText after writing to it. Actually, that entire Stream is unnecessary - this works:
using (MemoryStream base64Stream = new MemoryStream(base64byteArray))
{
using (GZipStream gzip = new GZipStream(
base64Stream, CompressionMode.Decompress))
{
string deserialized = Serializer.Deserialize<string>(gzip);
Assert.IsNotNull(deserialized);
Assert.AreEqual(data, deserialized);
}
}
Likewise, this should work for the serialize:
using (MemoryStream compressed = new MemoryStream())
{
using (GZipStream gzip = new GZipStream(
compressed, CompressionMode.Compress, true))
{
Serializer.Serialize(gzip, data);
}
serializedBase64 = Convert.ToBase64String(
compressed.GetBuffer(), 0, (int)compressed.Length);
}
I am having an issue with this test function where I take an in memory string, compress it, and decompress it. The compression works great, but I can't seem to get the decompression to work.
//Compress
System.IO.MemoryStream outStream = new System.IO.MemoryStream();
GZipStream tinyStream = new GZipStream(outStream, CompressionMode.Compress);
mStream.Position = 0;
mStream.CopyTo(tinyStream);
//Decompress
outStream.Position = 0;
GZipStream bigStream = new GZipStream(outStream, CompressionMode.Decompress);
System.IO.MemoryStream bigStreamOut = new System.IO.MemoryStream();
bigStream.CopyTo(bigStreamOut);
//Results:
//bigStreamOut.Length == 0
//outStream.Position == the end of the stream.
I believe that bigStream out should at least have data in it, especially if my source stream (outStream) is being read. is this a MSFT bug or mine?
What happens in your code is that you keep opening streams, but you never close them.
In line 2, you create a GZipStream. This stream will not write anything to the underlying stream until it feels it’s the right time. You can tell it to by closing it.
However, if you close it, it will close the underlying stream (outStream) too. Therefore you can’t use mStream.Position = 0 on it.
You should always use using to ensure that all your streams get closed. Here is a variation on your code that works.
var inputString = "“ ... ”";
byte[] compressed;
string output;
using (var outStream = new MemoryStream())
{
using (var tinyStream = new GZipStream(outStream, CompressionMode.Compress))
using (var mStream = new MemoryStream(Encoding.UTF8.GetBytes(inputString)))
mStream.CopyTo(tinyStream);
compressed = outStream.ToArray();
}
// “compressed” now contains the compressed string.
// Also, all the streams are closed and the above is a self-contained operation.
using (var inStream = new MemoryStream(compressed))
using (var bigStream = new GZipStream(inStream, CompressionMode.Decompress))
using (var bigStreamOut = new MemoryStream())
{
bigStream.CopyTo(bigStreamOut);
output = Encoding.UTF8.GetString(bigStreamOut.ToArray());
}
// “output” now contains the uncompressed string.
Console.WriteLine(output);
This is a known issue: http://blogs.msdn.com/b/bclteam/archive/2006/05/10/592551.aspx
I have changed your code a bit so this one works:
var mStream = new MemoryStream(new byte[100]);
var outStream = new System.IO.MemoryStream();
using (var tinyStream = new GZipStream(outStream, CompressionMode.Compress))
{
mStream.CopyTo(tinyStream);
}
byte[] bb = outStream.ToArray();
//Decompress
var bigStream = new GZipStream(new MemoryStream(bb), CompressionMode.Decompress);
var bigStreamOut = new System.IO.MemoryStream();
bigStream.CopyTo(bigStreamOut);
The way to compress and decompress to and from a MemoryStream is:
public static Stream Compress(
Stream decompressed,
CompressionLevel compressionLevel = CompressionLevel.Fastest)
{
var compressed = new MemoryStream();
using (var zip = new GZipStream(compressed, compressionLevel, true))
{
decompressed.CopyTo(zip);
}
compressed.Seek(0, SeekOrigin.Begin);
return compressed;
}
public static Stream Decompress(Stream compressed)
{
var decompressed = new MemoryStream();
using (var zip = new GZipStream(compressed, CompressionMode.Decompress, true))
{
zip.CopyTo(decompressed);
}
decompressed.Seek(0, SeekOrigin.Begin);
return decompressed;
}
This leaves the compressed / decompressed stream open and as such usable after creating it.
Another implementation, in VB.NET:
Imports System.Runtime.CompilerServices
Imports System.IO
Imports System.IO.Compression
Public Module Compressor
<Extension()> _
Function CompressASCII(str As String) As Byte()
Dim bytes As Byte() = Encoding.ASCII.GetBytes(str)
Using ms As New MemoryStream
Using gzStream As New GZipStream(ms, CompressionMode.Compress)
gzStream.Write(bytes, 0, bytes.Length)
End Using
Return ms.ToArray
End Using
End Function
<Extension()> _
Function DecompressASCII(compressedString As Byte()) As String
Using ms As New MemoryStream(compressedString)
Using gzStream As New GZipStream(ms, CompressionMode.Decompress)
Using sr As New StreamReader(gzStream, Encoding.ASCII)
Return sr.ReadToEnd
End Using
End Using
End Using
End Function
Sub TestCompression()
Dim input As String = "fh3o047gh"
Dim compressed As Byte() = input.CompressASCII()
Dim decompressed As String = compressed.DecompressASCII()
If input <> decompressed Then
Throw New ApplicationException("failure!")
End If
End Sub
End Module
public static byte[] compress(byte[] data)
{
using (MemoryStream outStream = new MemoryStream())
{
using (GZipStream gzipStream = new GZipStream(outStream, CompressionMode.Compress))
using (MemoryStream srcStream = new MemoryStream(data))
srcStream.CopyTo(gzipStream);
return outStream.ToArray();
}
}
public static byte[] decompress(byte[] compressed)
{
using (MemoryStream inStream = new MemoryStream(compressed))
using (GZipStream gzipStream = new GZipStream(inStream, CompressionMode.Decompress))
using (MemoryStream outStream = new MemoryStream())
{
gzipStream.CopyTo(outStream);
return outStream.ToArray();
}
}
If you are attempting to use the MemoryStream (e.g. passing it into another function) but receiving the Exception "Cannot access a closed Stream." then there is another GZipStream constructor you can use that will help you.
By passing in a true to the leaveOpen parameter, you can instruct GZipStream to leave the stream open after disposing of itself, by default it closes the target stream (which I didn't expect). https://msdn.microsoft.com/en-us/library/27ck2z1y(v=vs.110).aspx
using (FileStream fs = File.OpenRead(f))
using (var compressed = new MemoryStream())
{
//Instruct GZipStream to leave the stream open after performing the compression.
using (var gzipstream = new GZipStream(compressed, CompressionLevel.Optimal, true))
fs.CopyTo(gzipstream);
//Do something with the memorystream
compressed.Seek(0, SeekOrigin.Begin);
MyFunction(compressed);
}
I had an issue where *.CopyTo(stream)* would end up with a byte[0] result.
The solution was to add .Position=0 before calling .CopyTo(stream)
Answered here
I also use a BinaryFormatter that would throw an 'End of stream encountered before parsing was completed' exception if position was not set to 0 before deserialization.
Answered here
This is the code that worked for me.
public static byte[] SerializeAndCompressStateInformation(this IPluginWithStateInfo plugin, Dictionary<string, object> stateInfo)
{
byte[] retArr = new byte[] { byte.MinValue };
try
{
using (MemoryStream msCompressed = new MemoryStream())//what gzip writes to
{
using (GZipStream gZipStream = new GZipStream(msCompressed, CompressionMode.Compress))//setting up gzip
using (MemoryStream msToCompress = new MemoryStream())//what the settings will serialize to
{
BinaryFormatter formatter = new BinaryFormatter();
//serialize the info into bytes
formatter.Serialize(msToCompress, stateInfo);
//reset to 0 to read from beginning byte[0] fix.
msToCompress.Position = 0;
//this then does the compression
msToCompress.CopyTo(gZipStream);
}
//the compressed data as an array of bytes
retArr = msCompressed.ToArray();
}
}
catch (Exception ex)
{
Logger.Error(ex.Message, ex);
throw ex;
}
return retArr;
}
public static Dictionary<string, object> DeserializeAndDecompressStateInformation(this IPluginWithStateInfo plugin, byte[] stateInfo)
{
Dictionary<string, object> settings = new Dictionary<string, object>();
try
{
using (MemoryStream msDecompressed = new MemoryStream()) //the stream that will hold the decompressed data
{
using (MemoryStream msCompressed = new MemoryStream(stateInfo))//the compressed data
using (GZipStream gzDecomp = new GZipStream(msCompressed, CompressionMode.Decompress))//the gzip that will decompress
{
msCompressed.Position = 0;//fix for byte[0]
gzDecomp.CopyTo(msDecompressed);//decompress the data
}
BinaryFormatter formatter = new BinaryFormatter();
//prevents 'End of stream encountered' error
msDecompressed.Position = 0;
//change the decompressed data to the object
settings = formatter.Deserialize(msDecompressed) as Dictionary<string, object>;
}
}
catch (Exception ex)
{
Logger.Error(ex.Message, ex);
throw ex;
}
return settings;
}
I thought I would share this answer for anyone interested in reproducing this on PowerShell, the code is mostly inspired from Timwi's helpful answer, however unfortunately as of now there is no implementation for the using statement like on C# for PowerShell, hence the need to manually dispose the streams before output.
Functions below requires PowerShell 5.0+.
Required using statements and ArgumentCompleter for -Encoding Parameter.
Improved versions of these 2 functions as well as Compression From File Path and Expansion from File Path can be found in this repo as well as in the PowerShell Gallery.
using namespace System.Text
using namespace System.IO
using namespace System.IO.Compression
using namespace System.Collections
using namespace System.Management.Automation
using namespace System.Collections.Generic
using namespace System.Management.Automation.Language
Add-Type -AssemblyName System.IO.Compression
class EncodingCompleter : IArgumentCompleter {
[IEnumerable[CompletionResult]] CompleteArgument (
[string] $commandName,
[string] $parameterName,
[string] $wordToComplete,
[CommandAst] $commandAst,
[IDictionary] $fakeBoundParameters
) {
[CompletionResult[]] $arguments = foreach($enc in [Encoding]::GetEncodings().Name) {
if($enc.StartsWith($wordToComplete)) {
[CompletionResult]::new($enc)
}
}
return $arguments
}
}
Compression from string to Base64 GZip compressed string:
function Compress-GzipString {
[cmdletbinding()]
param(
[Parameter(Mandatory, ValueFromPipeline)]
[string] $String,
[Parameter()]
[ArgumentCompleter([EncodingCompleter])]
[string] $Encoding = 'utf-8',
[Parameter()]
[CompressionLevel] $CompressionLevel = 'Optimal'
)
try {
$enc = [Encoding]::GetEncoding($Encoding)
$outStream = [MemoryStream]::new()
$gzip = [GZipStream]::new($outStream, [CompressionMode]::Compress, $CompressionLevel)
$inStream = [MemoryStream]::new($enc.GetBytes($string))
$inStream.CopyTo($gzip)
}
catch {
$PSCmdlet.WriteError($_)
}
finally {
$gzip, $outStream, $inStream | ForEach-Object Dispose
}
try {
[Convert]::ToBase64String($outStream.ToArray())
}
catch {
$PSCmdlet.WriteError($_)
}
}
Expansion from Base64 GZip compressed string to string:
function Expand-GzipString {
[cmdletbinding()]
param(
[Parameter(Mandatory, ValueFromPipeline)]
[string] $String,
[Parameter()]
[ArgumentCompleter([EncodingCompleter])]
[string] $Encoding = 'utf-8'
)
try {
$enc = [Encoding]::GetEncoding($Encoding)
$bytes = [Convert]::FromBase64String($String)
$outStream = [MemoryStream]::new()
$inStream = [MemoryStream]::new($bytes)
$gzip = [GZipStream]::new($inStream, [CompressionMode]::Decompress)
$gzip.CopyTo($outStream)
$enc.GetString($outStream.ToArray())
}
catch {
$PSCmdlet.WriteError($_)
}
finally {
$gzip, $outStream, $inStream | ForEach-Object Dispose
}
}
And for the little Length comparison, querying the Loripsum API:
$loremIp = Invoke-RestMethod loripsum.net/api/10/long
$compressedLoremIp = Compress-GzipString $loremIp
$loremIp, $compressedLoremIp | Select-Object Length
Length
------
8353
4940
(Expand-GzipString $compressedLoremIp) -eq $loremIp # => Should be True
If you still need it, you can use GZipStream constructor wit boolean argument (there are two such constructors) and pass true value there:
tinyStream = new GZipStream(outStream, CompressionMode.Compress, true);
In that case, when you close your tynyStream, your out stream will be still opened. Don't forget to copy data:
mStream.CopyTo(tinyStream);
tinyStream.Close();
Now you've got memory stream outStream with zipped data
Bugs and kisses for U
Good luck
Please refer to below link, It is avoid to use double MemoryStream.
https://stackoverflow.com/a/53644256/1979406
I need to zip and unzip string
Here is code:
public static byte[] ZipStr(String str)
{
using (MemoryStream output = new MemoryStream())
using (DeflateStream gzip = new DeflateStream(output, CompressionMode.Compress))
using (StreamWriter writer = new StreamWriter(gzip))
{
writer.Write(str);
return output.ToArray();
}
}
and
public static string UnZipStr(byte[] input)
{
using (MemoryStream inputStream = new MemoryStream(input))
using (DeflateStream gzip = new DeflateStream(inputStream, CompressionMode.Decompress))
using (StreamReader reader = new StreamReader(gzip))
{
reader.ReadToEnd();
return System.Text.Encoding.UTF8.GetString(inputStream.ToArray());
}
}
It seems that there is error in UnZipStr method. Can somebody help me?
There are two separate problems. First of all, in ZipStr you need to flush or close the StreamWriter and close the DeflateStream before reading from the MemoryStream.
Secondly, in UnZipStr, you're constructing your result string from the compressed bytes in inputStream. You should be returning the result of reader.ReadToEnd() instead.
It would also be a good idea to specify the string encoding in the StreamWriter and StreamReader constructors.
Try the following code instead:
public static byte[] ZipStr(String str)
{
using (MemoryStream output = new MemoryStream())
{
using (DeflateStream gzip =
new DeflateStream(output, CompressionMode.Compress))
{
using (StreamWriter writer =
new StreamWriter(gzip, System.Text.Encoding.UTF8))
{
writer.Write(str);
}
}
return output.ToArray();
}
}
public static string UnZipStr(byte[] input)
{
using (MemoryStream inputStream = new MemoryStream(input))
{
using (DeflateStream gzip =
new DeflateStream(inputStream, CompressionMode.Decompress))
{
using (StreamReader reader =
new StreamReader(gzip, System.Text.Encoding.UTF8))
{
return reader.ReadToEnd();
}
}
}
}
I am trying to deserialize a stream but I always get this error "End of Stream encountered before parsing was completed"?
Here is the code:
//Some code here
BinaryFormatter b = new BinaryFormatter();
return (myObject)b.Deserialize(s);//s---> is a Stream object that has been fill up with data some line over here
Any one have ideas?
Try to set the position to 0 of your stream and do not use your object but the object type.
BinaryFormatter b = new BinaryFormatter();
s.Position = 0;
return (YourObjectType)b.Deserialize(s);
Make sure the serialization completed, and that the serialization type matches the de-serialization type (i.e., make sure you're serializing with a BinaryFormatter if you're de-serializing with one). Also, make sure that the stream you serialized to really finished serializing, with a Stream.Flush() or something to that effect.
I had the same exception thrown, until I added the [Serializable] tag to the class I was Serializing :)
Then it all worked perfectly.
In my case I used:
stream.Seek(0, SeekOrigin.Begin);
after i serialized the stream, and before i deserialized the stream works charm. hope this helps!
I have spent 5 hourse and have got end of stream error and lost data (Not obvious feature in GzipStream: you should use underlying stream only after flush GzipStream).
Full example of working code:
using System;
using System.IO;
using System.IO.Compression;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
namespace ConsoleApp3
{
class Program
{
static void Main(string[] args)
{
string large = LargeJsonContent.GetBigObject();
string base64;
using (var readStream = new MemoryStream())
using (var writeStream = new MemoryStream())
{
using (GZipStream compressor = new GZipStream(writeStream, CompressionMode.Compress, true)) //pay attention to leaveOpen = true
{
var formatter = new BinaryFormatter();
formatter.Serialize(readStream, large);
Console.WriteLine($"After binary serialization of JsonString: {readStream.Length} bytes");
readStream.Position = 0;
readStream.CopyTo(compressor);
}
Console.WriteLine($"Compressed stream size: {writeStream.Length} bytes");
writeStream.Position = 0;
byte[] writeBytes = writeStream.ToArray();
base64 = Convert.ToBase64String(writeBytes);
}
////
using (var stream = new MemoryStream())
{
var formatter = new BinaryFormatter();
formatter.Serialize(stream, base64);
Console.WriteLine($"Size of base64: {stream.Length} bytes");
}
Console.WriteLine("---------------------");
////
string large2;
var bytes = Convert.FromBase64String(base64);
using (var readStream = new MemoryStream())
{
readStream.Write(bytes, 0, bytes.Length);
readStream.Position = 0;
Console.WriteLine($"Compressed stream size: {readStream.Length} bytes");
using (var writeStream = new MemoryStream())
{
using (GZipStream decompressor = new GZipStream(readStream, CompressionMode.Decompress, true)) //pay attention to leaveOpen = true
{
decompressor.CopyTo(writeStream);
writeStream.Position = 0;
}
var formatter = new BinaryFormatter();
large2 = (string)formatter.Deserialize(writeStream);
}
}
Console.WriteLine(large == large2);
Console.WriteLine($"large:{large.Length} | large2:{large2.Length}");
}
}
}
Check in your sender code if you are not doing the following
NetworkStream strm = client.GetStream(); // the stream
formatter.Serialize(strm, status); // the serialization process
strm.Close();// Remove this code, this was the culprit in my case
the class which you created must has [Serializable].