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[英]Strange issue with NetworkStream and reading the first two bytes of a message
[英]NetworkStream cuts off first 4 bytes when reading
我遇到一個奇怪的問題。 當我嘗試通過TCP套接字發送文件時,發送的信息的前4個字節被切斷。
那就是發送和接收代碼。
客戶端
for (var i = 0; i < fileContentByte.Length; i += buffer.Length)
{
var size = (i + buffer.Length > fileContentByte.Length) ? fileContentByte.Length - i : buffer.Length;
clientSocket.Write(fileContentByte, i, size);
}
服務器端
using(var file = File.Create("C:\\test\\"+fileName.Substring(0, fileName.IndexOf('\0'))))
while(bytesReceived < numberOfBytes && (count = clientStream.Read(buffer, 0, buffer.Length)) > 0)
{
file.Write(buffer, 0, count);
bytesReceived += count;
}
這是完整代碼的鏈接-http://pastebin.com/VwTgTxgb
您在這里做的事情很奇怪。
首先,可以極大地簡化到Path.GetFileName()
調用的文件名檢索。
第二,您確定ASCII足夠嗎?
第三,對於概念驗證項目來說,將整個文件讀入內存是可以的,但是准備切換到流操作。
第四,您的協議有些古怪。 在發送可變大小的有效負載時,需要先告知接收方確切的發送多少字節。 這正是發送文件名時不執行的操作。
以下是幫助您入門的代碼段:
using System;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
namespace FolderSync
{
class Program
{
static void Main()
{
var server = new Server();
server.Start();
new Client().TransmitFile(
new IPEndPoint(IPAddress.Loopback, 35434),
@"f:\downloads\ubuntu-14.04.3-desktop-amd64.iso");
Console.ReadLine();
server.Stop();
}
}
class Server
{
private readonly TcpListener tcpListener;
public Server()
{
tcpListener = new TcpListener(IPAddress.Loopback, 35434);
}
public void Start()
{
tcpListener.Start();
tcpListener.BeginAcceptTcpClient(AcceptTcpClientCallback, null);
}
public void Stop()
{
tcpListener.Stop();
}
private void AcceptTcpClientCallback(IAsyncResult asyncResult)
{
//
// Big fat warning: http://stackoverflow.com/a/1230266/60188
tcpListener.BeginAcceptTcpClient(AcceptTcpClientCallback, null);
using(var tcpClient = tcpListener.EndAcceptTcpClient(asyncResult))
using(var networkStream = tcpClient.GetStream())
using(var binaryReader = new BinaryReader(networkStream, Encoding.UTF8))
{
var fileName = binaryReader.ReadString();
var length = binaryReader.ReadInt64();
var mib = length / 1024.0 / 1024.0;
Console.WriteLine("Receiving '{0}' ({1:N1} MiB)", fileName, mib);
var stopwatch = Stopwatch.StartNew();
var fullFilePath = Path.Combine(Path.GetTempPath(), fileName);
using(var fileStream = File.Create(fullFilePath))
networkStream.CopyTo(fileStream);
var elapsed = stopwatch.Elapsed;
Console.WriteLine("Received in {0} ({1:N1} MiB/sec)",
elapsed, mib / elapsed.TotalSeconds);
}
}
}
class Client
{
public void TransmitFile(IPEndPoint endPoint, string fileFullPath)
{
if(!File.Exists(fileFullPath)) return;
using(var tcpClient = new TcpClient())
{
tcpClient.Connect(endPoint);
using(var networkStream = tcpClient.GetStream())
using(var binaryWriter = new BinaryWriter(networkStream, Encoding.UTF8))
{
var fileName = Path.GetFileName(fileFullPath);
Debug.Assert(fileName != null, "fileName != null");
//
// BinaryWriter.Write(string) does length-prefixing automatically
binaryWriter.Write(fileName);
using(var fileStream = File.OpenRead(fileFullPath))
{
binaryWriter.Write(fileStream.Length);
fileStream.CopyTo(networkStream);
}
}
}
}
}
}
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