如何与TcpClient.ConnectAsync（）一起使用代理？

Question

.NET中的HTTP代理支持实际上并不支持较低级别的类，例如TcpClient或Socket。但我想通过支持“ CONNECT”命令的HTTP代理连接TCPServer（IP，端口）。

因此，我需要执行以下步骤：

1. 连接到代理。
2. 发送 CONNECT Host:Port HTTP/1.1<CR><LF>
3. 发送 <CR><LF>
4. 等待回应。如果包含HTTP/1.X 200，则连接成功。
5. 阅读更多响应行，直到收到空白行。
6. 它通过代理连接到外部世界。与代理进行任何可能的数据交换。

其实我没有代理就这样做

    TcpClient _client;
    NetworkStream _stream;

    public static async Task<bool> ConnectAsync(string hostname, int port)
    {
        _client = new TcpClient();
        await _client.ConnectAsync(hostname, port).ConfigureAwait(false);
        _stream = conn._client.GetStream();

        ..... Do some stuff

        // Connexion OK
        return true;
    }

在连接TcpClient之前如何使用代理和凭据？

Answer 1

我发现基于.NET的解决方案：通过具有身份验证的HTTP代理连接TcpClient并使用TcpClient绕过代理

TcpClient _client;
NetworkStream _stream;

public TcpClient ProxyTcpClient(string targetHost, int targetPort, string httpProxyHost, int httpProxyPort, string proxyUserName, string proxyPassword)
{
        const BindingFlags Flags = BindingFlags.NonPublic | BindingFlags.Instance;
        Uri proxyUri = new UriBuilder
        {
            Scheme = Uri.UriSchemeHttp,
            Host = httpProxyHost,
            Port = httpProxyPort
        }.Uri;
        Uri targetUri = new UriBuilder
        {
             Scheme = Uri.UriSchemeHttp,
             Host = targetHost,
             Port = targetPort
        }.Uri;

        WebProxy webProxy = new WebProxy(proxyUri, true);
        webProxy.Credentials = new NetworkCredential(proxyUserName, proxyPassword);
        WebRequest request = WebRequest.Create(targetUri);
        request.Proxy = webProxy;
        request.Method = "CONNECT";
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        Stream responseStream = response.GetResponseStream();
        Type responseType = responseStream.GetType();
        PropertyInfo connectionProperty = responseType.GetProperty("Connection", Flags);
        var connection = connectionProperty.GetValue(responseStream, null);
        Type connectionType = connection.GetType();
        PropertyInfo networkStreamProperty = connectionType.GetProperty("NetworkStream", Flags);
        NetworkStream networkStream = (NetworkStream)networkStreamProperty.GetValue(connection, null);
        Type nsType = networkStream.GetType();
        PropertyInfo socketProperty = nsType.GetProperty("Socket", Flags);
        Socket socket = (Socket)socketProperty.GetValue(networkStream, null);

        return new TcpClient { Client = socket };
}

public static async Task<bool> ConnectAsync(string hostname, int port)
{
        _client = ProxyTcpClient("IPTargetHost", 1234, "IPProxyHost", 5678, "Userproxy", "Userppwd");
        _stream = conn._client.GetStream();

        ..... Do some stuff

        // Connexion OK
        return true;
}