如何创建数据包标头？答案

【问题标题】：How Do I Create Packet Headers?如何创建数据包标头？
【发布时间】：2012-03-07 16:53:32
【问题描述】：

基本上，我通过客户端/服务器连接发送和接收图像、字符串和文件。我可以轻松地将协议用于字符串命令，但我无法区分传入的数据[如果数据是图像或其他，然后按照后续说明进行操作]。

那么如何使用 Dim 缓冲区作为 byte() 来制作数据包？

【问题讨论】：

为什么不能先发送一个控制字符？ 1=文本、2=图像等...然后您就会知道您收到了什么数据并采取相应的行动。

标签： .net vb.net sockets networking packet

【解决方案1】：

我只是粗略地猜测一下您要做什么。如果您使用 TCPListener 来处理传入的 HTTP 连接，您可以这样响应：

    Private Sub ServePNG()

        Dim stream As NetworkStream = mytcpclient.GetStream

        Dim Content As Byte() = System.IO.File.ReadAllBytes("image.png")

        Dim sb As New System.Text.StringBuilder
        sb.Append("HTTP/1.0 200 OK" + ControlChars.CrLf)
        sb.Append("Content-Type: image/png" + ControlChars.CrLf)
        sb.Append("Content-Length: " + Content.Length.ToString + ControlChars.CrLf)
        sb.Append(ControlChars.CrLf)

        Dim Header() As Byte = Encoding.ASCII.GetBytes(sb.ToString)
        stream.Write(Header, 0, Header.Length)
        stream.Write(Content, 0, Content.Length)

        client.Close()

    End Sub

我直接从 image.png 中得到字节数组

【讨论】：

【解决方案2】：

您可以创建一个包含Header Property 的新类，然后您可以序列化该类，然后将其转换为字节数组

例子：


Serializable()
    Public class Packet
    dim _header as packetHeader
    dim _data as byte()
    Public Property Header as packetHeader
    Get
    Return _Header
    End Get
    Set (byval value as packetHeader)
    _header = value
    End Set
    End Property
    Public Property Data as Object
    Get
    Return _Header
    End Get
    Set (byval value as Object)
    _data = value
    End Set
    End Property
    Public Sub New()
    End Sub
    Public Sub New(Byval header as packetHeader, Byval data as Object)
    _header = header
    _data = data
    End Sub
    Public Shared Function Serialize(myPacket as Packet) as Byte()
    Dim fs as New MemoryStream
    Dim formatter as New BinaryFormatter
    formatter.Serialize(fs, myPacket)
    Return fs.ToArray
    End Function
    Public Shared Function Deserialize(strm() as Byte) as Packet
    Dim fs as New MemoryStream(strm)
    Dim formatter as New BinaryFormatter
    Return DirectCast(formatter.Deserialize(fs),Packet)
    End Function
    End Class
    'Example of use
    Public Enum packetHeader as Integer
    Text = 0
    Image = 1
    'etc
    End Enum
    'Inside button click event (sending the packet)
    Dim bitmap as new Bitmap("C:/example.png")
    Dim data as Object =  bitmap
    Dim myPacket as new Packet(packetHeader.Image, data)
    dim buffer() as byte = Packet.Serialize(myPacket)
    'to deserialize the packet and check the header
    Dim buffer() as byte = stream.Read
    Dim myPacket as Packet = Packet.Deserialize(buffer)
    Select myPacket.Header
    Case packetHeader.Image
    Dim image as Bitmap
    image = DirectCast(myPacket.Data, Bitmap)
    Case packetHeader.Text
    Dim str as String
    str = DirectCast(myPacket.Data, String)
    End Select
    'do your proccess inside the Select statement

【讨论】：

抱歉格式错误...我是新来的>。