使用套接字接收文件时出现问题 - C＃ [英] Problem in receving file with socket - C#

问题描述

我正试图通过套接字从服务器发送文件到客户端（即时使用反向连接方法）

所以这是我的步骤：

0 - 向客户发送上传请求

1 - 阅读文件长度+文件名

2 - 向客户发送详细信息

3客户端将创建一个具有计算长度的字节数组

3从服务器读取文件到字节数组

4-send byte with socket.send（byte，0 ，byte.lenght，socketflag.none）



但问题是当我从客户端收到文件已收到时，我的文件坏了。

我该如何解决这个问题？



我的尝试：



ReceiveInfo（）方法用于客户端

 static private void ReceiveInfo（）//客户端接收数据检查它是否是正常命令或下载请求file 
 {
 byte [] buffer = new byte [1024]; 
 int received = 0; 
 
 try 
 {
 received = ClientSocket.Receive（buffer）; 
} 
 catch（SocketException）
 {
 // 
} 
 
如果（收到== 0）
返回; 
 
 byte [] data = new byte [received]; 
 System.Array.Copy（缓冲区，数据，已收到）; 
 
 if（IsDownload）
 {
 DownloadCommand（data）; 
} 
 
其他
 {
 NormalCommand（数据）; 
} 
 
} 

当我发送上传请求时，IsDownload的旗帜会改变真实。

以下是第3步:(当客户收到下载请求时）

 string [] info = //它包含详细信息file 
 FileName = info [1]; 
 FileSize = int.Parse（info [2]）; 
 FileBytes = new byte [FileSize]; 
 IsDownload = true; 

客户端收到信息，创建字节数组并等待服务器发送数据。 />

 public static void DownloadCommand（byte [] data）
 {
 
 
 Buffer.BlockCopy （data，0，FileBytes，WriteSize，data.Length）; 
 
 WriteSize + = data.Length; 
 
 
 if（FileBytes.Length == FileSize）
 {
 try 
 {
 using（FileStream fs = File.Create（FileName） ））
 {
 byte [] info = FileBytes; 
 fs.Write（info，0，info.Length）; 
} 
 
 Array.Clear（FileBytes，0，FileBytes.Length）; 
} 
 catch（exception ex）
 {
 
} 
 SendData（File Received。）; 
 IsDownload = false; 
 WriteSize = 0; 
} 
} 

这是服务器代码：

 public static void SendFile（Socket s，string fileName）
 {
 try 
 {
 if（s.Connected）
 {
 TargetClient = s; 
 byte [] dataToSend = File.ReadAllBytes（fileName）; 
 string fileInfo = Path.GetFileName（fileName）+〜+ dataToSend.Length; 
 SendCommand（IsDownload~+ fileInfo）; 
 TargetClient.Send（dataToSend，0，dataToSend.Length，SocketFlags.None）; 
} 
 
} 
 
 catch（exception ex）
 {
 LogManager.SetLog（SendFile中的错误（套接字，字符串）： \ n+ ex.Message）; 
}; 
 
} 

解决方案

你在接收函数中缺少一个循环，这意味着你只收到第一个一个文件的1024个字节。

请参见此处的示例：套接字发送和接收[C＃] [ ^ ]

和此处：使用C＃中的套接字 [ ^ ]

另一种方法是使用 WebClient（），这样可以简单得多： [ https://www.dotnetperls.com/webclient ]

Hi,
I'm trying to send a file over socket from server to client ( im using Reverse Connection method )
So here is my steps:
0-send a upload request to client
1-reading file lenght + filename
2-send details to client
3-client will create a byte array with the calculated length
3-reading file from server into byte array
4-send byte with socket.send(byte,0,byte.lenght,socketflag.none)

But the problem is when i receive the "File Received" from the client, my file is broken.
How can i fix this?

What I have tried:

The ReceiveInfo() method is for client-side

static private void ReceiveInfo() //Client receving data check if its a normal command or request to download a file
            {
                byte[] buffer = new byte[1024];
                int received = 0;

                try
                {
                    received = ClientSocket.Receive(buffer);
                }
                catch (SocketException)
                {
                    //
                }

                if (received == 0)
                    return;

                byte[] data = new byte[received];
                System.Array.Copy(buffer, data, received);

                if(IsDownload)
                {
                    DownloadCommand(data);
                }

                else
                {
                    NormalCommand(data);
                }

            }

when i send the upload request,the flag of IsDownload will change to true.
Here is the step 3: (when client recevies the download request)

string[] info = // it contains details of file
FileName = info[1];
FileSize = int.Parse(info[2]);
FileBytes = new byte[FileSize];
IsDownload = true;

Client receives the info,create byte array and waiting for server to send the data.

public static void DownloadCommand(byte[] data)
            {


                    Buffer.BlockCopy(data, 0, FileBytes, WriteSize, data.Length);

                    WriteSize += data.Length;


                if (FileBytes.Length == FileSize)
                {
                    try
                    {
                        using (FileStream fs = File.Create(FileName))
                        {
                            byte[] info = FileBytes;
                            fs.Write(info, 0, info.Length);
                        }

                        Array.Clear(FileBytes, 0, FileBytes.Length);
                    }
                    catch (Exception ex)
                    {

                    }
                    SendData("File Received.");
                    IsDownload = false;
                    WriteSize = 0;
                }
            }

And here is the server codes:

public static void SendFile(Socket s, string fileName)
            {
                try
                {
                    if (s.Connected)
                    {
                        TargetClient = s;
                        byte[] dataToSend = File.ReadAllBytes(fileName);
                        string fileInfo = Path.GetFileName(fileName) + "~" + dataToSend.Length;
                        SendCommand("IsDownload~" + fileInfo);
                        TargetClient.Send(dataToSend,0,dataToSend.Length,SocketFlags.None);
                    }

                }

                catch (Exception ex)
                {
                    LogManager.SetLog("Error in SendFile(Socket,string):\n" + ex.Message);
                };

            }

解决方案

You are missing a loop in your receive function, this means you only receive the first 1024 bytes of a file.
See example here: Socket Send and Receive [C#][^]
and here: Working with Sockets in C#[^]
An alternative is using WebClient(), which makes things a lot simpler: [https://www.dotnetperls.com/webclient]

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