Add http connect client

protocol/http/client.go

@@ -0,0 +1,93 @@
+package http
+
+import (
+	std_bufio "bufio"
+	"context"
+	"encoding/base64"
+	"net"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/sagernet/sing/common/buf"
+	"github.com/sagernet/sing/common/bufio"
+	E "github.com/sagernet/sing/common/exceptions"
+	M "github.com/sagernet/sing/common/metadata"
+	N "github.com/sagernet/sing/common/network"
+)
+
+var _ N.Dialer = (*Client)(nil)
+
+type Client struct {
+	dialer     N.Dialer
+	serverAddr M.Socksaddr
+	username   string
+	password   string
+}
+
+func NewClient(dialer N.Dialer, serverAddr M.Socksaddr, username string, password string) *Client {
+	return &Client{
+		dialer,
+		serverAddr,
+		username,
+		password,
+	}
+}
+
+func (c *Client) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
+	if !strings.HasPrefix(network, "tcp") {
+		return nil, os.ErrInvalid
+	}
+	var conn net.Conn
+	conn, err := c.dialer.DialContext(ctx, "tcp", c.serverAddr)
+	if err != nil {
+		return nil, err
+	}
+	destinationAddress := destination.String()
+	request := &http.Request{
+		Method: http.MethodConnect,
+		URL: &url.URL{
+			Host: destinationAddress,
+		},
+		Host: destinationAddress,
+		Header: http.Header{
+			"Proxy-Connection": []string{"Keep-Alive"},
+		},
+	}
+	if c.username != "" {
+		auth := c.username + ":" + c.password
+		request.Header.Add("Proxy-Authorization", "Basic "+base64.StdEncoding.EncodeToString([]byte(auth)))
+	}
+	err = request.Write(conn)
+	if err != nil {
+		return nil, err
+	}
+	reader := std_bufio.NewReader(conn)
+	response, err := http.ReadResponse(reader, request)
+	if err != nil {
+		return nil, err
+	}
+	switch response.StatusCode {
+	case http.StatusOK:
+		if reader.Buffered() > 0 {
+			buffer := buf.NewSize(reader.Buffered())
+			_, err = buffer.ReadFrom(reader)
+			if err != nil {
+				return nil, err
+			}
+			conn = bufio.NewCachedConn(conn, buffer)
+		}
+		return conn, nil
+	case http.StatusProxyAuthRequired:
+		return nil, E.New("authentication required")
+	case http.StatusMethodNotAllowed:
+		return nil, E.New("method not allowed")
+	default:
+		return nil, E.New("unexpected status: ", response.Status)
+	}
+}
+
+func (c *Client) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
+	return nil, os.ErrInvalid
+}