How to connect to HTTPS proxy?

I'm trying to connect to HTTPS server through proxy using sockets. As far as I know when using HTTP proxy one should connect socket to it and then interact with it as it is the real serv开发者_如何学Cer. With HTTP this approach works, but with HTTPS isn't. Why?

Here's simple program that connects to HTTPS server

using System;
using System.Text;
using System.Net.Sockets;
using System.Net.Security;

namespace SslTcpClient
{
    public class SslTcpClient
    {
        public static void Main(string[] args)
        {
            string host = "encrypted.google.com";
            string proxy = "127.0.0.1";//host;
            int proxyPort = 8888;//443;

            // Connect socket
            TcpClient client = new TcpClient(proxy, proxyPort);

            // Wrap in SSL stream
            SslStream sslStream = new SslStream(client.GetStream());
            sslStream.AuthenticateAsClient(host);

            // Send request
            byte[] request = Encoding.UTF8.GetBytes(String.Format("GET https://{0}/  HTTP/1.1\r\nHost: {0}\r\n\r\n", host));
            sslStream.Write(request);
            sslStream.Flush();

            // Read response
            byte[] buffer = new byte[2048];
            int bytes;
            do
            {
                bytes = sslStream.Read(buffer, 0, buffer.Length);
                Console.Write(Encoding.UTF8.GetString(buffer, 0, bytes));
            } while (bytes != 0);

            client.Close();
            Console.ReadKey();
        }
    }
}

It successfully connects when proxy = host and proxyPort = 443. But when I set them to 127.0.0.1:8888 (fiddler proxy on localhost) it doesn't work. Program hangs at sslStream.AuthenticateAsClient(host); Why? Fiddler supports HTTPS (browsers are able to connect through it).

P.S. No, I can't use HttpWebRequest in my case.

Managed to solve it myself. Here's the solution:

using System;
using System.Text;
using System.Net.Sockets;
using System.Net.Security;

namespace SslTcpClient
{
    public class SslTcpClient
    {
        public static void Main(string[] args)
        {
            string host = "encrypted.google.com";
            string proxy = "127.0.0.1";//host;
            int proxyPort = 8888;//443;

            byte[] buffer = new byte[2048];
            int bytes;

            // Connect socket
            TcpClient client = new TcpClient(proxy, proxyPort);
            NetworkStream stream = client.GetStream();

            // Establish Tcp tunnel
            byte[] tunnelRequest = Encoding.UTF8.GetBytes(String.Format("CONNECT {0}:443  HTTP/1.1\r\nHost: {0}\r\n\r\n", host));
            stream.Write(tunnelRequest , 0, tunnelRequest.Length);
            stream.Flush();

            // Read response to CONNECT request
            // There should be loop that reads multiple packets
            bytes = stream.Read(buffer, 0, buffer.Length);
            Console.Write(Encoding.UTF8.GetString(buffer, 0, bytes));

            // Wrap in SSL stream
            SslStream sslStream = new SslStream(stream);
            sslStream.AuthenticateAsClient(host);

            // Send request
            byte[] request = Encoding.UTF8.GetBytes(String.Format("GET https://{0}/  HTTP/1.1\r\nHost: {0}\r\n\r\n", host));
            sslStream.Write(request, 0, request.Length);
            sslStream.Flush();

            // Read response
            do
            {
                bytes = sslStream.Read(buffer, 0, buffer.Length);
                Console.Write(Encoding.UTF8.GetString(buffer, 0, bytes));
            } while (bytes != 0);

            client.Close();
            Console.ReadKey();
        }
    }
}