0

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 上打开一个 TcpListener。我从 Google Chrome 连接到我的 websocket 服务器（通过 AcceptSocket 方法）。我从 Chrome 向服务器发送请求，服务器可以读取它和所有内容。当我发回消息（如回显）时，我可以第一次发送它，但第二次我收到错误：

Received unexpected continuation frame.

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

这是可以实现的，如果可以，解决方案是什么？

我用SendMessage(sck, "test")

这是我的消息发件人的代码：

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：

将行更改为后Dim reply(bLength + 1) As Byte，Dim reply(bLength) As Byte我没有收到连续帧错误，而是收到了一个新错误：

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 与客户端一起做所有事情。从接受到握手再到消息。

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。通过更改它frame(1) = CByte(rawData.Length)来frame(1) = CByte(rawData.Length + 1)合并结束 0 字节，现在消息的正确长度是正确的，并且消除了我的屏蔽问题。我猜消息字节的结尾应该包含在消息长度中。

4

1 回答 1

1

看起来您在消息末尾包含了一个额外的字节。不应该线

Dim reply(bLength + 1) As Byte

改为

Dim reply(bLength) As Byte

反而？您在消息中只需要操作码 + 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的字节作为新消息的开始，从而有效地破坏您实际发送的下一条消息。

于 2013-01-31T08:58:24.523 回答