是否可以检测UDP响应编码？

Question

问题：

我通过 UDP 查询 Quake3 主服务器，并得到如下响应。 正如你所看到的，我很难弄清楚服务器发送的内容的编码...... 有没有办法检测或设置接收编码？

            baBuffer = new byte[1024*100]; // 100 kb should be enough
        int recv = sctServerConnection.ReceiveFrom(baBuffer, ref tmpRemote);

        Console.WriteLine("Message received from {0}:", tmpRemote.ToString());

        System.Text.Encoding encResponseEncoding = System.Text.Encoding.Default; // Wrong...
        //encResponseEncoding = System.Text.Encoding.ASCII;
        //encResponseEncoding = System.Text.Encoding.UTF8;
        //encResponseEncoding = System.Text.Encoding.GetEncoding(437); // ANSI-DOS
        //encResponseEncoding = System.Text.Encoding.GetEncoding(1252);// ANSI-WestEurope
        //encResponseEncoding = System.Text.Encoding.GetEncoding(1250); // Ansi-Centraleuro
        //encResponseEncoding = System.Text.Encoding.GetEncoding("ISO-8859-1");
        //encResponseEncoding = System.Text.Encoding.GetEncoding("ISO-8859-9");
        //encResponseEncoding = System.Text.Encoding.UTF32;
        encResponseEncoding = System.Text.Encoding.UTF7; // Bingo !

Answer 1

编码（如果它实际上是文本）由协议决定。如果您没有协议规范并且没有源代码，那么，是的，您将不得不猜测。

Answer 2

没有办法安全地检测编码，你只能猜测它。另请参阅如何检测文本文件的编码/代码页。

Answer 3

您可以查找字节顺序标记 (BOM)。这是我使用的一些 VB.Net 代码：

Private Shared Function GetStringFromBytes(ByVal bytes() As Byte) As String
    Dim ByteLegth = bytes.Count
    If (ByteLegth >= 3) AndAlso (bytes(0) = &HEF) AndAlso (bytes(1) = &HBB) AndAlso (bytes(2) = &HBF) Then
        Return System.Text.Encoding.UTF8.GetString(bytes)
    ElseIf (ByteLegth >= 2) AndAlso (bytes(0) = &HFE) AndAlso (bytes(1) = &HFF) Then
        Return System.Text.Encoding.BigEndianUnicode.GetString(bytes)
    ElseIf (ByteLegth >= 2) AndAlso (bytes(0) = &HFF) AndAlso (bytes(1) = &HFE) Then
        Return System.Text.Encoding.Unicode.GetString(bytes)
    ElseIf (ByteLegth >= 2) AndAlso (bytes(0) = &H0) AndAlso (bytes(1) = &H0) AndAlso (bytes(2) = &HFE) AndAlso (bytes(3) = &HFF) Then
        Return New System.Text.UTF32Encoding(True, True).GetString(bytes)
    ElseIf (ByteLegth >= 2) AndAlso (bytes(0) = &HFF) AndAlso (bytes(1) = &HFE) AndAlso (bytes(2) = &H0) AndAlso (bytes(3) = &H0) Then
        Return System.Text.Encoding.UTF32.GetString(bytes)
    Else
        'No BOM, assume ASCII
        Return System.Text.Encoding.ASCII.GetString(bytes)
    End If
End Function