Question

我目前正在编写一个Visual Basic脚本，在本地计算机ip（127.0.0.1）和端口8181上打开TcpListener。我从Google Chrome连接到我的websocket服务器（通过AcceptSocket方法）。从Chrome我发送一个发送请求到服务器，服务器可以读取它和一切。当我发回消息（如回声）时，我可以第一次发送它，但第二次发出错误：

Received unexpected continuation frame.

我需要的是一个CByte，告诉框架开始一个新的或结束一个开放的（不关闭套接字连接）

这是否可行，如果可以，解决方案是什么？

我用SendMessage(sck, "test")

调用Sub

以下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，我不会收到连续帧错误，而是会收到新错误：

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。

更新2：

以下是整个客户端Sub对客户端做的一切。从接受到握手到消息。

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）：

我已经弄清楚了我的问题。通过将frame(1) = CByte(rawData.Length)更改为frame(1) = CByte(rawData.Length + 1)，它会将结束0字节包含在内，现在消息的正确长度是正确的，并且让我知道我的屏蔽问题。我想消息字节的结尾应该包含在消息长度中。

Answer 1

看起来你在邮件末尾加了一个额外的字节。不应该行

Dim reply(bLength + 1) As Byte

改为

Dim reply(bLength) As Byte

代替？您在消息中需要的只是操作码+长度（frameCount）+消息（rawData.Length）。 websocket客户端将这些字节读作完整有效的消息。然后，它将从您的消息中读取剩余的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。

Websocket新帧字节

1 个答案: