c# - TCP/IP 消息帧

Question

我制作了一个 TCP/IP 服务器/客户端，它是异步的，但它连接了消息。我如何正确地在开头添加 header ，然后在末尾使用字符串生成器来取消连接完整的消息。

服务器读取消息:

  Private Sub ReadCallback(ByVal result As IAsyncResult)
    Try
        allDone.Set()
        Dim success As Boolean = result.AsyncWaitHandle.WaitOne(500, True)
        If success Then
            Dim client As ServerClient = TryCast(result.AsyncState, ServerClient)
            If client Is Nothing Then
                Return
            End If
            Dim networkStream As NetworkStream = client.NetworkStream
            Dim read As Integer = networkStream.EndRead(result)
            If read = 0 Then
                SyncLock Me.Clients
                    Me.Clients.Remove(client.ClientID)
                    Return
                End SyncLock
            End If
            If client.NetworkStream.CanRead Then

                dataString.Append(Me.Encoding.GetString(client.buffer, 0, read))

                networkStream.BeginRead(client.buffer, 0, client.buffer.Length, AddressOf ReadCallback, client)
                allDone.WaitOne(500, True)
            End If
        End If
    Catch ex As IO.IOException
        Dim client As ServerClient = TryCast(result.AsyncState, ServerClient)
        SyncLock Me.Clients
            Me.Clients.Remove(client.ClientID)
            Return
        End SyncLock
    Catch ex As Exception
        If Not Me.tcpListener.Server.Connected Then
            Return
        End If
    End Try
End Sub

客户端写消息:

    Public Function Write(value As String, encoding As Encoding) As Guid
    Dim buffer As Byte() = encoding.GetBytes(value)
    Return Me.Write(buffer)
End Function

Public Function Write(buffer As Byte()) As Guid
    Dim guid__1 As Guid = Guid.NewGuid()
    Dim networkStream As NetworkStream = Me.client.GetStream()
    Dim result As IAsyncResult = networkStream.BeginWrite(buffer, 0, buffer.Length, Nothing, guid__1)


    result.AsyncWaitHandle.WaitOne()
    networkStream.EndWrite(result)
    Return guid__1
End Function

Answer 1

您需要在 TCP/IP 之上定义一个(可能很简单的)协议(protocol)，以允许您知道一条消息的开始和结束位置。 TCP/IP 可以并且将会对您发送的消息进行分段，以便接收方可以获得消息的一部分、整条消息或多条消息。一个简单的方法是写一个消息长度，然后是消息。接收方然后读入字节缓冲区，一旦接收到适当数量的字节(基于发送的长度)，就可以提取消息并将其编码为字符串。