I have the following constructor method which opens a MemoryStream from a file path:
MemoryStream _ms;
public MyClass(string filePath)
{
byte[] docBytes = File.ReadAllBytes(filePath);
_ms = new MemoryStream();
_ms.Write(docBytes, 0, docBytes.Length);
}
I need to change this to accept a Stream instead of a file path. Whats the easiest/most efficient way to get a MemoryStream from the Stream object?
In .NET 4, you can use Stream.CopyTo to copy a stream, instead of the home-brew methods listed in the other answers.
MemoryStream _ms;
public MyClass(Stream sourceStream)
_ms = new MemoryStream();
sourceStream.CopyTo(_ms);
}
Use this:
var memoryStream = new MemoryStream();
stream.CopyTo(memoryStream);
This will convert Stream to MemoryStream.
If you're modifying your class to accept a Stream instead of a filename, don't bother converting to a MemoryStream. Let the underlying Stream handle the operations:
public class MyClass
{
Stream _s;
public MyClass(Stream s) { _s = s; }
}
But if you really need a MemoryStream for internal operations, you'll have to copy the data out of the source Stream into the MemoryStream:
public MyClass(Stream stream)
{
_ms = new MemoryStream();
CopyStream(stream, _ms);
}
// Merged From linked CopyStream below and Jon Skeet's ReadFully example
public static void CopyStream(Stream input, Stream output)
{
byte[] buffer = new byte[16*1024];
int read;
while((read = input.Read (buffer, 0, buffer.Length)) > 0)
{
output.Write (buffer, 0, read);
}
}
You can simply do:
var ms = new MemoryStream(File.ReadAllBytes(filePath));
Stream position is 0 and ready to use.
You will have to read in all the data from the Stream object into a byte[] buffer and then pass that into the MemoryStream via its constructor. It may be better to be more specific about the type of stream object you are using. Stream is very generic and may not implement the Length attribute, which is rather useful when reading in data.
Here's some code for you:
public MyClass(Stream inputStream) {
byte[] inputBuffer = new byte[inputStream.Length];
inputStream.Read(inputBuffer, 0, inputBuffer.Length);
_ms = new MemoryStream(inputBuffer);
}
If the Stream object doesn't implement the Length attribute, you will have to implement something like this:
public MyClass(Stream inputStream) {
MemoryStream outputStream = new MemoryStream();
byte[] inputBuffer = new byte[65535];
int readAmount;
while((readAmount = inputStream.Read(inputBuffer, 0, inputBuffer.Length)) > 0)
outputStream.Write(inputBuffer, 0, readAmount);
_ms = outputStream;
}
I use this combination of extension methods:
public static Stream Copy(this Stream source)
{
if (source == null)
return null;
long originalPosition = -1;
if (source.CanSeek)
originalPosition = source.Position;
MemoryStream ms = new MemoryStream();
try
{
Copy(source, ms);
if (originalPosition > -1)
ms.Seek(originalPosition, SeekOrigin.Begin);
else
ms.Seek(0, SeekOrigin.Begin);
return ms;
}
catch
{
ms.Dispose();
throw;
}
}
public static void Copy(this Stream source, Stream target)
{
if (source == null)
throw new ArgumentNullException("source");
if (target == null)
throw new ArgumentNullException("target");
long originalSourcePosition = -1;
int count = 0;
byte[] buffer = new byte[0x1000];
if (source.CanSeek)
{
originalSourcePosition = source.Position;
source.Seek(0, SeekOrigin.Begin);
}
while ((count = source.Read(buffer, 0, buffer.Length)) > 0)
target.Write(buffer, 0, count);
if (originalSourcePosition > -1)
{
source.Seek(originalSourcePosition, SeekOrigin.Begin);
}
}
How do I copy the contents of one stream to another?
see that. accept a stream and copy to memory. you should not use .Length for just Stream because it is not necessarily implemented in every concrete Stream.
public static void Do(Stream in)
{
_ms = new MemoryStream();
byte[] buffer = new byte[65536];
while ((int read = input.Read(buffer, 0, buffer.Length))>=0)
_ms.Write (buffer, 0, read);
}
byte[] fileData = null;
using (var binaryReader = new BinaryReader(Request.Files[0].InputStream))
{
fileData = binaryReader.ReadBytes(Request.Files[0].ContentLength);
}
Related
I am calling a WebAPI that returns a PDF in a ConnectStream. I write that ConnectStream to a file and then read it back in to a memorystream and I can attach it to an email. How can I accomplish the same thing without the IO overhead?
System.Net.HttpWebResponse webResponse = (System.Net.HttpWebResponse)webRequest.GetResponse();
System.IO.Stream stream = webResponse.GetResponseStream();
System.IO.StreamReader reader = new System.IO.StreamReader(stream, Encoding.Default);
string finalPath = System.IO.Path.Combine(outputPath, $"{startDate:yyyy-MM-dd}_{endDate:yyyy-MM-dd}.pdf");
System.IO.Stream fileStream = System.IO.File.OpenWrite(finalPath);
using (System.IO.StreamWriter sw = new System.IO.StreamWriter(fileStream, Encoding.Default))
{
sw.Write(reader.ReadToEnd());
sw.Flush();
sw.Close();
}
using (MemoryStream ms = new MemoryStream(File.ReadAllBytes(finalPath)))
{
using (MailMessage mailMessage = new MailMessage())
{
mailMessage.From = new MailAddress("noreply#somedomain.com");
mailMessage.To.Add("someone#somedomain.com");
mailMessage.Attachments.Add(new Attachment(ms, new System.Net.Mime.ContentType(System.Net.Mime.MediaTypeNames.Application.Pdf)));
SmtpClient smtpClient = new SmtpClient() { DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.SpecifiedPickupDirectory, PickupDirectoryLocation = outputPath };
smtpClient.Send(mailMessage);
}
}
First, the request stream is a one-way read only stream and cannot be passed to most methods that allow a stream, so you need to read it into something you can manipulate:
public byte[] ReadStreamBinary(Stream stream, int bufferSize)
{
using (var ms = new MemoryStream())
{
var buffer = CreateBuffer(bufferSize);
var finished = false;
while (!finished)
{
buffer.Initialize();
var bytes = stream.Read(buffer, 0, buffer.Length);
if (bytes > 0)
{
ms.Write(buffer, 0, bytes);
}
else
{
finished = true;
}
}
return ms.ToArray();
}
}
Then you can just create your MemoryStream from this array of bytes.
Since the default internal buffer for a stream is 4k, I almost always use that as my buffer size (4096). In your case, it may be easier to just modify the method to return the MemoryStream directly.
If you decide to return the stream, you'll need to remove the using (so the stream won't get closed/disposed) and return the stream pointer to the beginning.
public MemoryStream ReadStreamBinary(Stream stream, int bufferSize)
{
var ms = new MemoryStream();
var buffer = CreateBuffer(bufferSize);
var finished = false;
while (!finished)
{
buffer.Initialize();
var bytes = stream.Read(buffer, 0, buffer.Length);
if (bytes > 0)
{
ms.Write(buffer, 0, bytes);
}
else
{
finished = true;
}
}
ms.Seek(0, SeekOrigin.Begin);
return ms;
}
Just remember to close/dispose of the stream in the calling method.
Oops. almost forgot to include the CreateBuffer code, just put this anywhere in your class:
public static Func<int, byte[]> CreateBuffer = x => (byte[])Array.CreateInstance(typeof(byte), x);
I receive a zip file base64 string, convert to byte[], open in memory, modify content, and then 'compress' the new byte[] to base64 string again.
My problem, I don't know how to 'compress' the new byte[] to zip format.
public string ModifyZipContent(string base64) {
ZipPackage zipPackage = null;
MemoryStream memoryStream = null;
long lenght;
byte[] data = Convert.FromBase64String(base64);
byte[] buffer;
byte[] newData;
int arrayOffset = 0;
memoryStream = new MemoryStream();
memoryStream.Write(data, 0, data.Length);
zipPackage = (ZipPackage)Package.Open(memoryStream, FileMode.Open);
PackagePartCollection zipParts = zipPackage.GetParts();
// this is awful
foreach(ZipPackagePart zipPart in zipParts) {
using(Stream stream = zipPart.GetStream()) {
arrayOffset += (int)stream.Length;
}
}
newData = new byte[arrayOffset];
// end
arrayOffset = 0;
foreach(ZipPackagePart zipPart in zipParts) {
using(Stream stream = zipPart.GetStream()) {
lenght = stream.Length;
buffer = new byte[lenght];
stream.Read(buffer, 0, (int)lenght);
Buffer.BlockCopy(buffer, 0, newData, arrayOffset, buffer.Length);
arrayOffset += buffer.Length;
}
}
return Convert.ToBase64String(newData);
}
I haven't fully tested this, but something along these lines should work...
// Requires System.IO.Compression using statement.
byte[] bytes = new byte[256]; // Your byte[] would be here instead of this empty one.
using (var zipFile = ZipFile.Open("C:/ZipFile.zip", ZipArchiveMode.Update))
{
var entry = zipFile.CreateEntry("YourEntryPathHere");
using (var stream = entry.Open())
{
stream.Write(bytes, 0, bytes.Length);
}
}
i'm using the following function to compress(thanks to http://www.dotnetperls.com/):
public static void CompressStringToFile(string fileName, string value)
{
// A.
// Write string to temporary file.
string temp = Path.GetTempFileName();
File.WriteAllText(temp, value);
// B.
// Read file into byte array buffer.
byte[] b;
using (FileStream f = new FileStream(temp, FileMode.Open))
{
b = new byte[f.Length];
f.Read(b, 0, (int)f.Length);
}
// C.
// Use GZipStream to write compressed bytes to target file.
using (FileStream f2 = new FileStream(fileName, FileMode.Create))
using (GZipStream gz = new GZipStream(f2, CompressionMode.Compress, false))
{
gz.Write(b, 0, b.Length);
}
}
and for decompress:
static byte[] Decompress(byte[] gzip)
{
// Create a GZIP stream with decompression mode.
// ... Then create a buffer and write into while reading from the GZIP stream.
using (GZipStream stream = new GZipStream(new MemoryStream(gzip), CompressionMode.Decompress))
{
const int size = 4096;
byte[] buffer = new byte[size];
using (MemoryStream memory = new MemoryStream())
{
int count = 0;
do
{
count = stream.Read(buffer, 0, size);
if (count > 0)
{
memory.Write(buffer, 0, count);
}
}
while (count > 0);
return memory.ToArray();
}
}
}
so my goal is actually compress log files and than to decompress them in memory and compare the uncompressed file to the original file in order to check that the compression succeeded and i'm able to open the compressed file successfuly.
the problem is that the uncompressed file is most of the time bigger than the original file and my compare check is failing altough the compression probably succeeded.
any idea why ?
btw here how i compare the uncompressed file to the original file:
static bool FileEquals(byte[] file1, byte[] file2)
{
if (file1.Length == file2.Length)
{
for (int i = 0; i < file1.Length; i++)
{
if (file1[i] != file2[i])
{
return false;
}
}
return true;
}
return false;
}
Try this method to compress a file:
public static byte[] Compress(byte[] raw)
{
using (MemoryStream memory = new MemoryStream())
{
using (GZipStream gzip = new GZipStream(memory,
CompressionMode.Compress, true))
{
gzip.Write(raw, 0, raw.Length);
}
return memory.ToArray();
}
}
}
And this to decompress :
static byte[] Decompress(byte[] gzip)
{
// Create a GZIP stream with decompression mode.
// ... Then create a buffer and write into while reading from the GZIP stream.
using (GZipStream stream = new GZipStream(new MemoryStream(gzip), CompressionMode.Decompress))
{
const int size = 4096;
byte[] buffer = new byte[size];
using (MemoryStream memory = new MemoryStream())
{
int count = 0;
do
{
count = stream.Read(buffer, 0, size);
if (count > 0)
{
memory.Write(buffer, 0, count);
}
}
while (count > 0);
return memory.ToArray();
}
}
}
}
Tell me if it worked.
Goodluck.
Think you'd be better off with the simplest API call, try Stream.CopyTo(). I can't find the error in your code. If I was working on it, I'd probably make sure everything is getting flushed properly.. can't recall if GZipStream is going to flush its output to FileStream when the using block closes.. but then you are also saying that the final file is larger, not smaller.
Anyhow, best policy in my experience.. don't rewrite gotcha prone code when you don't need to. At least you tested it ;)
I am trying to send a FileStream of a file.
But I now want to add 40 byte Checksum to the start.
How can I do this? Ive tried creating my own stream class to concatinate two streams.. And Ive looked at stream writers.
Surely they must be an easy way. Or an alternative way. And I DONT want to load the entire file into a byte array, appead to that and write that back to a stream.
public Stream getFile(String basePath, String path) {
return new FileStream(basePath + path, FileMode.Open, FileAccess.Read);
}
See MergeStream.cs. Here's how you can use it:
var mergeStream = new MergeStream(new MemoryStream(checksum), File.OpenRead(path));
return mergeStream;
byte[] checksum = new byte[40];
//...
FileStream oldFileStream = new FileStream(oldFile, FileMode.Open, FileAccess.Read);
FileStream newFileStream = new FileStream(newFile, FileMode.Create, FileAccess.Write);
using(oldFileStream)
using(newFileStream)
{
newFileStream.Write(checksum, 0, checksum.Length);
oldFileStream.CopyTo(newFileStream);
}
File.Copy(newFile, oldFile, overwrite : true);
If you don't want to use a temporary file, the only solution is to open the file in ReadWrite mode and use two alternating buffers:
private static void Swap<T>(ref T obj1, ref T obj2)
{
T tmp = obj1;
obj1 = obj2;
obj2 = tmp;
}
public static void PrependToFile(string filename, byte[] bytes)
{
FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.ReadWrite);
PrependToStream(stream, bytes);
}
public static void PrependToStream(Stream stream, byte[] bytes)
{
const int MAX_BUFFER_SIZE = 4096;
using(stream)
{
int bufferSize = Math.Max(MAX_BUFFER_SIZE, bytes.Length);
byte[] buffer1 = new byte[bufferSize];
byte[] buffer2 = new byte[bufferSize];
int readCount1;
int readCount2;
long totalLength = stream.Length + bytes.Length;
readCount1 = stream.Read(buffer1, 0, bytes.Length);
stream.Position = 0;
stream.Write(bytes, 0, bytes.Length);
int written = bytes.Length;
while (written < totalLength)
{
readCount2 = stream.Read(buffer2, 0, buffer2.Length);
stream.Position -= readCount2;
stream.Write(buffer1, 0, readCount1);
written += readCount1;
Swap(ref buffer1, ref buffer2);
Swap(ref readCount1, ref readCount2);
}
}
}
How do I convert a WaveStream to a Byte Array using NAudio?
public static class StreamExtension
{
public static byte[] ToArray(this Stream stream)
{
byte[] buffer = new byte[4096];
int reader = 0;
MemoryStream memoryStream = new MemoryStream();
while ((reader = stream.Read(buffer, 0, buffer.Length)) != 0)
memoryStream.Write(buffer, 0, reader);
return memoryStream.ToArray();
}
}
You can try this vision and should work for you, try it
MemoryStream memoryStr = new MemoryStream();
while ((read = stream.Read(buffer, 0, buffer.Length)) != 0)
memoryStr.Write(buffer, 0, read );
You use it like a System.IO.Stream.
Use the Read Method. But remember. If you convert the whole stream into ONE Bytearray it could cause and OutOfMemoryException. It depends on how big the stream is. But you could use something like this:
byte[] buffer = new byte[stream.Length];
int read = stream.Read(buffer, 0, buffer.Length);