发送服务器多条消息？ C＃ [英] Send server multiple messages? C#

问题描述

我有一个快速和肮脏的问题。因此，我有两个客户端和一个服务器运行。我可以从客户端到服务器的消息，没有任何问题。我的问题出现时，我想从客户端读取两个消息，而不只是一个消息。

I have a quick and dirty question. So as it stands, i have two clients and a server running. I can communicate messages from the clients to the server without any problem. my problem appears when i want to read two messages from the client - rather than just one message.

我收到的错误是：IOException未处理。无法从传输连接读取数据：远程主机强制关闭了现有连接。

The error which i receive is: IOException was unhandled. Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

这是我的代码在服务器端：

Here is my code on the server side:

private static void HandleClientComm（object client）
{
/ **创建一个包含DatabaseFile对象的列表** /
List theDatabase = new List（）;

private static void HandleClientComm(object client) { /** creating a list which contains DatabaseFile objects **/ List theDatabase = new List();

        TcpClient tcpClient = (TcpClient)client;
        NetworkStream clientStream = tcpClient.GetStream();

        byte[] message = new byte[4096];
        int bytesRead;

        do
        {
            bytesRead = 0;

            try
            {
                // Blocks until a client sends a message                    
                bytesRead = clientStream.Read(message, 0, 4096);
            }
            catch (Exception)
            {
                // A socket error has occured
                break;
            }

            if (bytesRead == 0)
            {
                // The client has disconnected from the server
                break;
            }

            // Message has successfully been received
            ASCIIEncoding encoder = new ASCIIEncoding();

            Console.WriteLine("To: " + tcpClient.Client.LocalEndPoint);
            Console.WriteLine("From: " + tcpClient.Client.RemoteEndPoint);
            Console.WriteLine(encoder.GetString(message, 0, bytesRead));


            if (encoder.GetString(message, 0, bytesRead) == "OptionOneInsert")
            {
                byte[] message2 = new byte[4096];
                int bytesRead2 = 0;

                **bytesRead2 = clientStream.Read(message, 0, 4096);** //ERROR occurs here!

                Console.WriteLine("Attempting to go inside insert)");
                Menu.Insert(theDatabase, bytesRead2); 
            }

这是我的客户代码：

        ASCIIEncoding encoder = new ASCIIEncoding();
        byte[] buffer = encoder.GetBytes("OptionOneInsert");

        Console.ReadLine(); 
        clientStream.Write(buffer, 0, buffer.Length);
        clientStream.Flush();

        NetworkStream clientStream2 = client.GetStream();
        String text = System.IO.File.ReadAllText("FirstNames.txt");
        clientStream2.Write(buffer, 0, buffer.Length);
        clientStream2.Flush();
        ASCIIEncoding encoder2 = new ASCIIEncoding();

        byte[] buffer2 = encoder2.GetBytes(text);
        Console.WriteLine("buffer is filled with content"); 
        Console.ReadLine();

当客户端发送消息optionOne时，服务器接收到它。只有当我试图发送一个名为文本的字符串，问题出现！

When the client sends the message "optionOne" it is received by the server just fine. It's only when i attempt to send the string called "text" that the issues appears!

任何帮助将非常感激 - 我不是所有熟悉的插座，

Any help would be greatly appreciated - I'm not all that familiar with Sockets, hence i've been struggling with trying to understand this for sometime now

推荐答案

你有一个大

避免的最简单的方法是每个消息前缀与其中的字节数，例如作为固定的四字节格式。因此，要发送消息，您将：

The simplest way of avoiding that is to prefix each message with the number of bytes in it, e.g. as a fixed four-byte format. So to send a message you would:

• 将其从字符串编码为字节（理想情况下使用UTF-8，确保您将从不需要任何非ASCII文本）


• 将字节数组的长度写为四字节值


• 写出内容

• Encoding it from a string to bytes (ideally using UTF-8 instead of ASCII unless you're sure you'll never need any non-ASCII text)
• Write out the length of the byte array as a four-byte value
• Write out the content

在服务器上：

• 读取四个字节（如有必要，循环） -


• 将四个字节整数


• 分配该大小的字节数组


• 循环，从当前位置读取到缓冲区结尾，直到

• Read four bytes (looping if necessary - there's no guarantee you'd even read those four bytes together, although you almost certainly will)
• Convert the four bytes into an integer
• Allocate a byte array of that size
• Loop round, reading from "the current position" to the end of the buffer until you've filled the buffer
• Convert the buffer into a string

另一种替代方法是简单地将缓冲区转换为字符串使用 BinaryReader 和 BinaryWriter - ReadString 和<$ c

Another alternative is simply to use BinaryReader and BinaryWriter - the ReadString and WriteString use length-prefixing, admittedly in a slightly different form.

使用长度加前缀是有分隔符（例如回车），但这意味着如果您需要在文本中包含分隔符以传输，则需要添加转义。

Another alternative you could use is to have a delimiter (e.g. carriage-return) but that means you'll need to add escaping in if you ever need to include the delimiter in the text to transmit.

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