glider/proxy/ws/client.go

package ws

import (
	"bufio"
	"errors"
	"io"
	"net"
	"net/textproto"
	"strings"

	"github.com/nadoo/glider/common/log"
)

// Client ws client
type Client struct {
	host string
	path string
}

// Conn is a connection to ws server
type Conn struct {
	net.Conn
	reader io.Reader
	writer io.Writer
}

// NewClient .
func NewClient(host, path string) (*Client, error) {
	if path == "" {
		path = "/"
	}
	c := &Client{host: host, path: path}
	return c, nil
}

// NewConn .
func (c *Client) NewConn(rc net.Conn, target string) (*Conn, error) {
	conn := &Conn{Conn: rc}
	return conn, conn.Handshake(c.host, c.path)
}

// Handshake handshakes with the server using HTTP to request a protocol upgrade
func (c *Conn) Handshake(host, path string) error {
	c.Conn.Write([]byte("GET " + path + " HTTP/1.1\r\n"))
	// c.Conn.Write([]byte("Host: 127.0.0.1\r\n"))
	c.Conn.Write([]byte("Host: " + host + "\r\n"))
	c.Conn.Write([]byte("Upgrade: websocket\r\n"))
	c.Conn.Write([]byte("Connection: Upgrade\r\n"))
	c.Conn.Write([]byte("Origin: http://" + host + "\r\n"))
	c.Conn.Write([]byte("Sec-WebSocket-Key: w4v7O6xFTi36lq3RNcgctw==\r\n"))
	c.Conn.Write([]byte("Sec-WebSocket-Protocol: binary\r\n"))
	c.Conn.Write([]byte("Sec-WebSocket-Version: 13\r\n"))
	c.Conn.Write([]byte("\r\n"))

	tpr := textproto.NewReader(bufio.NewReader(c.Conn))
	_, code, _, ok := parseFirstLine(tpr)
	if !ok || code != "101" {
		return errors.New("error in ws handshake")
	}

	// respHeader, err := tpr.ReadMIMEHeader()
	// if err != nil {
	// 	return err
	// }

	// // TODO: verify this
	// respHeader.Get("Sec-WebSocket-Accept")
	// fmt.Printf("respHeader: %+v\n", respHeader)

	return nil
}

func (c *Conn) Write(b []byte) (n int, err error) {
	if c.writer == nil {
		c.writer = FrameWriter(c.Conn)
	}

	return c.writer.Write(b)
}

func (c *Conn) Read(b []byte) (n int, err error) {
	if c.reader == nil {
		c.reader = FrameReader(c.Conn)
	}

	return c.reader.Read(b)
}

// parseFirstLine parses "GET /foo HTTP/1.1" OR "HTTP/1.1 200 OK" into its three parts.
// TODO: move to seperate http lib package for reuse(also for http proxy module)
func parseFirstLine(tp *textproto.Reader) (r1, r2, r3 string, ok bool) {
	line, err := tp.ReadLine()
	// log.F("first line: %s", line)
	if err != nil {
		log.F("[http] read first line error:%s", err)
		return
	}

	s1 := strings.Index(line, " ")
	s2 := strings.Index(line[s1+1:], " ")
	if s1 < 0 || s2 < 0 {
		return
	}
	s2 += s1 + 1
	return line[:s1], line[s1+1 : s2], line[s2+1:], true
}