Websocket 新帧字节



我目前正在编写一个Visual Basic脚本,该脚本在本地机器ip(127.0.0.1)和端口8181上打开TcpListener。我从谷歌浏览器连接到我的websocket服务器(通过AcceptSocket方法)。从Chrome,我向服务器发出发送请求,服务器可以读取它和所有内容。当我发回消息(如回声)时,我可以第一次发送它,但第二次出现错误:

Received unexpected continuation frame.

我需要的是一个 CByte,它告诉帧开始一个新的框架或结束打开的框架(不关闭套接字连接)

这是否可实现,如果是,解决方案是什么?

我用SendMessage(sck, "test")称潜艇

这是我的邮件发件人的代码:

Sub SendMessage(sck As Socket, message As String)
    Dim rawData = System.Text.Encoding.UTF8.GetBytes(message)
    Dim frameCount = 0
    Dim frame(10) As Byte
    frame(0) = CByte(129)
    If rawData.Length <= 125 Then
        frame(1) = CByte(rawData.Length)
        frameCount = 2
    ElseIf rawData.Length >= 126 AndAlso rawData.Length <= 65535 Then
        frame(1) = CByte(126)
        Dim len = CByte(rawData.Length)
        frame(2) = CByte(((len >> 8) & CByte(255)))
        frame(3) = CByte((len & CByte(255)))
        frameCount = 4
    Else
        frame(1) = CByte(127)
        Dim len = CByte(rawData.Length)
        frame(2) = CByte(((len >> 56) & CByte(255)))
        frame(3) = CByte(((len >> 48) & CByte(255)))
        frame(4) = CByte(((len >> 40) & CByte(255)))
        frame(5) = CByte(((len >> 32) & CByte(255)))
        frame(6) = CByte(((len >> 24) & CByte(255)))
        frame(7) = CByte(((len >> 16) & CByte(255)))
        frame(8) = CByte(((len >> 8) & CByte(255)))
        frame(9) = CByte((len & CByte(255)))
        frameCount = 10
    End If
    Dim bLength = frameCount + rawData.Length
    Console.WriteLine(frameCount)
    Console.WriteLine(rawData.Length)
    Dim reply(bLength + 1) As Byte
    Dim bLim = 0
    For i = 0 To frameCount - 1
        Console.WriteLine(bLim)
        reply(bLim) = frame(i)
        bLim += 1
    Next
    For i = 0 To rawData.Length - 1
        Console.WriteLine(bLim)
        reply(bLim) = rawData(i)
        bLim += 1
    Next
    For i = 0 To reply.Length - 1
        Console.WriteLine("Byte: " & reply(i))
        Console.WriteLine("Char: " & CByte(reply(i)))
    Next
    sck.Send(reply, reply.Length, 0)
End Sub

更新:

将行Dim reply(bLength + 1) As Byte更改为Dim reply(bLength) As Byte后,我没有收到连续帧错误,而是收到一个新错误:

A server must not mask any frames that it sends to the client.

希望这些信息可以指出问题所在。

更新 2:

下面是整个客户端 Sub 对客户端执行所有操作。从接受到握手再到消息内容。

Private Sub clientStarter(ByVal sck As Socket)
    Dim netStream As New NetworkStream(sck)
    Dim netReader As New IO.StreamReader(netStream)
    Dim netWriter As New IO.StreamWriter(netStream)
    Dim key As String = ""
    Console.WriteLine("Accept new connection ...")
    '' Reading handshake message
    While (True)
        Dim line As String = netReader.ReadLine()
        If line.Length = 0 Then
            Exit While
        End If
        If (line.StartsWith("Sec-WebSocket-Key: ")) Then
            key = line.Split(":")(1).Trim()
        End If
        Console.WriteLine("Data: " & line)
    End While
    '' Calculate accept-key
    key += "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
    key = getSHA1Hash(key)
    '' Response handshake message
    Dim response As String
    response = "HTTP/1.1 101 Switching Protocols" & vbCrLf
    response &= "Upgrade: websocket" & vbCrLf
    response &= "Connection: Upgrade" & vbCrLf
    response &= "Sec-WebSocket-Accept: " & key & vbCrLf & vbCrLf
    netWriter.Write(response)
    netWriter.Flush()
    Dim dataSent As [Byte]() = Nothing
    Dim dataRecieved(1024) As [Byte]
    Dim bytes As Int32
    Console.WriteLine(dataRecieved)
    Dim message As String = Nothing
    While (True)
        If (sck.Connected = False) Then
            Exit While
        End If
        bytes = sck.Receive(dataRecieved, dataRecieved.Length, 0)
        'Console.WriteLine(bytes)
        While (bytes > 0)
            Console.WriteLine("recieved Data")
            message = System.Text.Encoding.UTF8.GetString(dataRecieved, 0, bytes)
            Console.WriteLine(bytes)
            bytes = 0
            If (bytes = 0) Then
                Console.WriteLine("test")
                Console.WriteLine(message)
                dataSent = System.Text.Encoding.UTF8.GetBytes(message, 0, bytes)
                SendMessage(sck, "test")
                message = Nothing
            End If
        End While
    End While
End Sub

更新 3(解决方案):

我已经解决了我的问题。通过将frame(1) = CByte(rawData.Length)更改为frame(1) = CByte(rawData.Length + 1)它合并了结尾 0 字节,现在消息的正确长度是正确的,让我摆脱了屏蔽问题。我想消息字节的末尾应该包含在消息长度中。

看起来您在消息末尾包含一个额外的字节。 不应该是行

Dim reply(bLength + 1) As Byte

更改为

Dim reply(bLength) As Byte

相反? 消息中所需要的只是操作码 + 长度 ( frameCount ) + 消息 ( rawData.Length )。 websocket 客户端会将这些字节作为完整的有效消息读取。 然后,它将从您的消息中读取剩余字节作为新消息的开头,从而有效地破坏您实际发送的下一条消息。

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