networkcomms2.3.1通信框架实现大文件传输（为节省空间，不包含通信框架源码，通信框架源码请另行下载）
文件传送在TCP通信中是经常用到的，本文针对文件传送进行探讨
经过测试，可以发送比较大的文件，比如1个G或者2个G
本文只对文件传送做了简单的探讨，示例程序可能也不是很成熟，希望本文起到抛砖引玉的作用，有兴趣的朋友帮忙补充完善
首先看一下实现的效果
服务器端：
客户端（一次只能发送一个文件)：
服务器端收到的文件，存放到了D盘根目录下（存放的路径可以根据情况修改)
本程序基于开源的networkcomms2.3.1通信框架
下面来看一下实现的步骤：
1、客户端
（1）： 先连接服务器：
//给连接信息对象赋值
connInfo = new ConnectionInfo(txtIP.Text, int.Parse(txtPort.Text));
//如果不成功，会弹出异常信息
newTcpConnection = TCPConnection.GetConnection(connInfo);
TCPConnection.StartListening(connInfo.LocalEndPoint);
button1.Enabled = false;
button1.Text = "连接成功";
（2）发送大文件（分段发送)
private void SendFileButton_Click(object sender, EventArgs e)
{
//打开对话框，获取文件
if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
//暂时禁用发送按钮
sendFileButton.Enabled = false;
//获取对话框中选择的文件的名称
string filename = openFileDialog1.FileName;
//设置进度条显示为0
UpdateSendProgress(0);
try
{
//创建一个文件流
FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read);
//创建一个线程安全流
ThreadSafeStream safeStream = new ThreadSafeStream(stream);
//获取不包含路径的文件名称
string shortFileName = System.IO.Path.GetFileName(filename);
//每次发送的字节数 可根据实际情况进行设定
long sendChunkSizeBytes = 40960;
//已发送的字节数
long totalBytesSent = 0;
do
{
//检查剩余的字节数 小于 上面指定的字节数 则发送"剩余的字节数" 否则发送"指定的字节数"
long bytesToSend = (totalBytesSent + sendChunkSizeBytes < stream.Length ? sendChunkSizeBytes : stream.Length - totalBytesSent);
//包装一个ThreadSafeStream 使之可以分段发送
StreamSendWrapper streamWrapper = new StreamSendWrapper(safeStream, totalBytesSent, bytesToSend);
//顺序号
long packetSequenceNumber;
//发送指定数据
newTcpConnection.SendObject("PartialFileData", streamWrapper, customOptions, out packetSequenceNumber);
//发送指定的数据相关的信息
newTcpConnection.SendObject("PartialFileDataInfo", new SendInfo(shortFileName, stream.Length, totalBytesSent, packetSequenceNumber), customOptions);
totalBytesSent += bytesToSend;
UpdateSendProgress((double)totalBytesSent / stream.Length);
//两次发送之间间隔一定时间 掼蛋(www.gamefrye.com)
System.Threading.Thread.Sleep(30);
} while (totalBytesSent < stream.Length);
}
catch (CommunicationException)
{
}
catch (Exception ex)
{
NetworkComms.LogError(ex, "SendFileError");
}
}
}
2：服务器端接收文件：
（1）开始监听
//服务器开始监听客户端的请求
//开始监听某T端口
IPEndPoint thePoint = new IPEndPoint(IPAddress.Parse(txtIP.Text), int.Parse(txtPort.Text));
TCPConnection.StartListening(thePoint, false);
button1.Text = "监听中";
button1.Enabled = false;
//此方法中包含服务器具体的处理方法。
StartListening();
（2）添加接收文件处理方法
//处理收到的文件字节数据
NetworkComms.AppendGlobalIncomingPacketHandler<byte[]>("PartialFileData", IncomingPartialFileData);
//处理收到的文件信息数据
NetworkComms.AppendGlobalIncomingPacketHandler<SendInfo>("PartialFileDataInfo", IncomingPartialFileDataInfo);
//处理收到的文件字节数据
private void IncomingPartialFileData(PacketHeader header, Connection connection, byte[] data)
{
try
{
SendInfo info = null;
ReceivedFile file = null;
lock (syncRoot)
{
//获取顺序号
long sequenceNumber = header.GetOption(PacketHeaderLongItems.PacketSequenceNumber);
if (incomingDataInfoCache.ContainsKey(connection.ConnectionInfo) && incomingDataInfoCache[connection.ConnectionInfo].ContainsKey(sequenceNumber))
{
//如果已经收到此部分 “文件字节数据” 对应的 “文件信息数据”
info = incomingDataInfoCache[connection.ConnectionInfo][sequenceNumber];
incomingDataInfoCache[connection.ConnectionInfo].Remove(sequenceNumber);
if (!receivedFilesDict.ContainsKey(connection.ConnectionInfo))
receivedFilesDict.Add(connection.ConnectionInfo, new Dictionary<string, ReceivedFile>());
//如果当前收到字节数据，还没有对应的ReceivedFile类，则创建一个
if (!receivedFilesDict[connection.ConnectionInfo].ContainsKey(info.Filename))
{
receivedFilesDict[connection.ConnectionInfo].Add(info.Filename, new ReceivedFile(info.Filename, connection.ConnectionInfo, info.TotalBytes));
}
file = receivedFilesDict[connection.ConnectionInfo][info.Filename];
}
else
{
if (!incomingDataCache.ContainsKey(connection.ConnectionInfo))
incomingDataCache.Add(connection.ConnectionInfo, new Dictionary<long, byte[]>());
incomingDataCache[connection.ConnectionInfo].Add(sequenceNumber, data);
}
}
if (info != null && file != null && !file.IsCompleted)
{
file.AddData(info.BytesStart, 0, data.Length, data);
file = null;
data = null;
}
else if (info == null ^ file == null)
throw new Exception("Either both are null or both are set. Info is " + (info == null ? "null." : "set.") + " File is " + (file == null ? "null." : "set.") + " File is " + (file.IsCompleted ? "completed." : "not completed."));
}
catch (Exception ex)
{
NetworkComms.LogError(ex, "IncomingPartialFileDataError");
}
}
//处理收到的文件信息数据
private void IncomingPartialFileDataInfo(PacketHeader header, Connection connection, SendInfo info)
{
try
{
byte[] data = null;
ReceivedFile file = null;
lock (syncRoot)
{
//获取顺序号
long sequenceNumber = info.PacketSequenceNumber;
if (incomingDataCache.ContainsKey(connection.ConnectionInfo) && incomingDataCache[connection.ConnectionInfo].ContainsKey(sequenceNumber))
{
//如果当前文件信息类对应的文件字节部分已经存在
data = incomingDataCache[connection.ConnectionInfo][sequenceNumber];
incomingDataCache[connection.ConnectionInfo].Remove(sequenceNumber);
if (!receivedFilesDict.ContainsKey(connection.ConnectionInfo))
receivedFilesDict.Add(connection.ConnectionInfo, new Dictionary<string, ReceivedFile>());
if (!receivedFilesDict[connection.ConnectionInfo].ContainsKey(info.Filename))
{
receivedFilesDict[connection.ConnectionInfo].Add(info.Filename, new ReceivedFile(info.Filename, connection.ConnectionInfo, info.TotalBytes));
}
file = receivedFilesDict[connection.ConnectionInfo][info.Filename];
}
else
{
if (!incomingDataInfoCache.ContainsKey(connection.ConnectionInfo))
incomingDataInfoCache.Add(connection.ConnectionInfo, new Dictionary<long, SendInfo>());
incomingDataInfoCache[connection.ConnectionInfo].Add(sequenceNumber, info);
}
}
if (data != null && file != null && !file.IsCompleted)
{
file.AddData(info.BytesStart, 0, data.Length, data);
file = null;
data = null;
}
else if (data == null ^ file == null)
throw new Exception("Either both are null or both are set. Data is " + (data == null ? "null." : "set.") + " File is " + (file == null ? "null." : "set.") + " File is " + (file.IsCompleted ? "completed." : "not completed."));
}
catch (Exception ex)
{
NetworkComms.LogError(ex, "IncomingPartialFileDataInfo");
}
}
临时存储文件数据用到的字典类
ReceivedFile方法
3.在MessageContract类库中添加SendInfo契约类方法，此方法用于传递文件信息，客户端和服务器端都需要使用
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ProtoBuf;
namespace MessageContract
{
/// <summary>
/// 文件信息类
/// </summary>
[ProtoContract]
public class SendInfo
{
/// <summary>
/// 文件名称
/// </summary>
[ProtoMember(1)]
public string Filename { get; private set; }
/// <summary>
/// 文件发送-开始位置
/// </summary>
[ProtoMember(2)]
public long BytesStart { get; private set; }
/// <summary>
/// 文件大小
/// </summary>
[ProtoMember(3)]
public long TotalBytes { get; private set; }
/// <summary>
/// 顺序号
/// </summary>
[ProtoMember(4)]
public long PacketSequenceNumber { get; private set; }
/// <summary>
/// 私有构造函数 用来反序列化
/// </summary>
private SendInfo() { }
/// <summary>
/// 创建一个新的实例
/// </summary>
/// <param name="filename">文件名称 Filename corresponding to data</param>
/// <param name="totalBytes">文件大小 Total bytes of the whole ReceivedFile</param>
/// <param name="bytesStart">开始位置 The starting point for the associated data</param>
/// <param name="packetSequenceNumber">顺序号 Packet sequence number corresponding to the associated data</param>
public SendInfo(string filename, long totalBytes, long bytesStart, long packetSequenceNumber)
{
this.Filename = filename;
this.TotalBytes = totalBytes;
this.BytesStart = bytesStart;
this.PacketSequenceNumber = packetSequenceNumber;
}
}
}